past:2009 [Summer Research Institute]

This is an old revision of the document!

23/04/2009 @ 12:15 room GC A3 30

Impulse waves in the laboratory and in nature

Prof. Dr. Willi H. HAGER, VAW, ETH ZURICH
05/10/2009 @ 16:15 room GR B3 30

Fire Safety and Sustainable Infrastructure and Communities

Prof. José L. Torero, University Edinburgh UK

It has been recognized that urban development and the accompanying infrastructure needs to be designed and maintained in a sustainable way. Much effort has been made on understanding energy management, life cycles and environmental sustainability; in contrast the role of safety (in specific fire safety) as a threat to the sustainability of communities has been largely ignored. Fire Safety is a complex problem that encompasses issues as diverse as structural behaviour, toxicology or water management.
Furthermore, the specific problems involved require time and length scale resolution that range from the nano-metre and nano-second to the kilometres and hours. This presentation will highlight the link between Fire Safety and sustainable development. A series of examples will be selected to describe the fundamental research areas being explored and the potential impact on urban development. The examples will include linking micro-pollutants to fire retardants and its impact on fire management, understanding of novel structural components and materials and their impact on construction and architecture, the impact of urban development on Urban-Wildland-Interface (UWI) fires and the impact of modern sensor technology on the structure of the fire service.
26/10/2009 @ 16:15 room GR B3 30

Geomechanical Know-how in Design of Underground Isolation System for Nuclear Waste

Prof Lyesse Laloui, Soil Mechanics Laboratory, IIC-ENAC

In all nuclear power generating countries, the management of spent nuclear fuel and long-lived radioactive waste is an important environmental issue. A promising option for waste disposal is the burial in deep clay geological formations. A safety analysis for a geological repository for high-level and/or long-lived radioactive waste needs to be addressed both in repository design and in performance assessment. Therefore analyses and predictions about the behaviour of isolation barriers need to be based on robust science. This implies a good understanding of the fundamental behaviour of the argillaceous materials and state-of-the-art modelling. In many proposals for deep geological repositories in Europe, the argillaceous materials constitute either the main barrier or an important element of the multi-barrier system. They can be either the host material or engineered parts of the repository (i.e. buffer materials such as compacted swelling clays). The purpose of this seminar is to show the know-how of the Soil Mechanics group of EPFL, in identifying the fundamental mechanical behaviours of argillaceous materials in the context of deep repository experiments and analysing them in a new comprehensive Thermo-Hydro-Mechanical stress-strain constitutive framework.
10/11/2009 @ 12:15 room CM013

The role of shared space in traffic engineering

Prof. Michael Bell, Imperial college London
26/11/2009 @ 12:15 room GC A3 31

Introducing metrobus: Design and operation of efficient bus networks in Barcelona

Prof. Francesc Robusté Antón, Universitat Politècnica de Catalunya
10/12/2009 @ 12:15 room GC A3 31

Robotics in construction

Prof. Thomas Bock
25/01/2010 @ 15:00 room GC B3 424

A Stochastic and Dynamic Policy-Oriented Model of a Large Network of Airports

Prof. Amedeo Odoni, Massachusetts Institute of Technology

As more airports in the United States and in Europe become congested, it also becomes increasingly likely that delays at one or more airports will spread to other parts of the network. We describe an analytical model, Airport Network Delays (AND), developed to study this complex phenomenon. It computes delays due to local congestion at individual airports and, more important, captures the "ripple effect" that leads to the propagation of local delays throughout the network. The model operates by iterating between a stochastic and dynamic queuing engine (QE) that computes delays at individual airports and a delay propagation algorithm that updates flight schedules at all the airports in the model in response to the local delays computed by the QE.
The AND model is fast computationally, making possible the exploration of the impacts of a large number of scenarios and policies on system-wide delays. It has been fully implemented for the network of the 34 busiest airports in the continental United States. An implementation for the network of the 34 busiest airports in Europe is in progress. The model provides insights into the complex interactions through which delays propagate through the network and the often-counterintuitive consequences of these interactions. (joint work with PhD student Nikolas Pyrgiotis)
23/02/2010 @ 17:15 room CM 1 3

Advanced Traffic Management using Behavioral Models and Network Simulation

Professeur Moshe E. Ben-Akiva, MIT

Conférence sur inscription >> s'inscrire en ligne
Abstract In the event of natural (e.g. a snow storm) or man-made (e.g. new-year celebration) events, transportation networks are a vulnerable and critical infrastructure. Properly managing both the increase in travel demand and the capacity loss can determine the success of a traffic management system. Models of drivers' behavior and traffic simulation are used to evaluate and refine traffic management plans for foreseen events, as well as to tailor them in real time as events unfold. The technique combines three critical pieces: 1) behavioral models, which simulate individual travelers' decision-making, 2) dynamic traffic assignment, which simulates the movements of vehicles on the road network, and 3) data from traffic surveillance systems (e.g. counts and speeds from loop detectors and point-to-point travel times from probe vehicles), which are used to calibrate the behavior and network models. The outputs of such a model system are short-term predictions of the network conditions. Travelers' information provision and potential mitigation plans can then be evaluated based on predicted network conditions. Two advanced traffic simulation systems developed at the MIT Intelligent Transportation Systems Laboratory – MITSIMLab and DynaMIT – will be presented along with sample applications to real-world traffic management problems.
La conférence sera suivie d'un apéritif !
25/02/2010 @ 12:15 room GC A3 30

A multi-scale approach for modeling the mechanical behavior of granular materials

Prof. Pierre-Yves HICHER, Ecole Centrale Nantes
11/03/2010 @ 12:15 room CM 0 12

Optimal Mainstream Traffic Flow Control of Large Scale Motorway Networks

Prof. Markos Papageorgiou, Technical University of Crete

Abstract: The continuously increasing daily traffic congestions on motorway networks around the world call for innovative control measures that would drastically improve the current traffic conditions. Mainstream traffic flow control (MTFC) is proposed as a novel and efficient motorway traffic management tool, and its possible implementation and principal impact on traffic flow efficiency is analysed. Variable speed limits, suitably operated and enforced, is considered as one (out of several possible) way(s) for MTFC realisation, either as a stand-alone measure or in combination with ramp metering. A previously developed, computationally efficient software tool for optimal integrated motorway network traffic control including MTFC is applied to a large-scale motorway ring-road. It is demonstrated via several investigated control scenarios that traffic flow can be substantially improved via MTFC with or without integration with coordinated ramp metering actions.
22/03/2010 @ 16:15 room CM 1 3

Structural Design of the Learning Centre

Prof. Mandfred Grohmann, owner Bollinger+Grohmann, Frankfurt am Main
15/04/2010 @ 12:15 room GC A3 30

The tragedy of cooperation within couples Decision making and mobility

André de-Palma , Ecole Normale Supérieure de Cachan

ABSTRACT
Individuals in couples tend to behave cooperatively and empirical evidence suggests that their decisions are Pareto efficient. However, most of the literature has examined couples in isolation without studying the consequences of their decisions for society as a whole. This paper develops a theoretical model to study trip-timing decisions of couples in the context of the morning commute by automobile when there is traffic congestion. Three settings are compared: (a) individuals living alone, (b) couples living together who make independent, non-cooperative decisions, and (c) couples who make cooperative decisions. Finally, we briefly discuss the implications of these results on the optimal manner to determine control and pricing.
BIO
André de Palma has a PhD in Physics and one in Economics. He is a specialist in transportation economics, and industrial organization. He has developed the software METROPOLIS, a dynamic model of traffic congestion. He has published more than 200 articles in Transportation, Economics, and Operations Research Journal, and has written/edited 5 books. He is currently teaching at Ecole Normale Supérieure de Cachan and at Ecole Polytechnique, in Paris. He is a senior member of Institut universitaire de France.
27/04/2010 @ 12:15 room CO 124

Advances in the study of bedload sediment transport in gravel-bed rivers

Prof. André G. Roy, Chaire de recherche du Canada en dynamique fluviale, Département de géographie, Université de Montréal

Estimating bedload sediment transport is critical for the maintenance of river bed morphology and channel stability. In spite of its importance, bedload sediment transport is very difficult to measure and evaluate in situ. Several techniques provide measures at limited spatial and temporal scales, thus limiting their usefulness for estimating sediment transport rates and sedimentary budgets. This presentation has two objectives. Firstly, we will briefly review a set of techniques to measure bedload transport in rivers and will examine their potential and efficiency as a function of the objectives and spatiotemporal scales of the study. Several innovations offer new avenues in particular for monitoring the displacement of individual clasts. For example, passive transponders (PIT tags) and accelerometres are now used for an efficient tracking of pebbles in gravel-bed rivers and they are informative on the modes of transport. Secondly, we will present the results from two studies illustrating the usefulness of combining techniques and approaches to gain insights on the role of turbulence in the movement of particles as bedload and on the dynamics of a small gravel-bed river. In the first study, we have used video images taken simultaneously with measures of the flow velocity fluctuations with the objective of linking turbulent flow properties and the motion of particles. Results show that fluid acceleration and deceleration are critical variables to explain sediment transport events. The figure below shows that transport events of individual particles are generally associated with combinations of streamwise and vertical velocity acceleration values that are larger than those observed during periods without transport. In a second study, we have gathered observations in a 6 meter wide gravel-bed river from sediment traps, tagged particles, topographic measures of the river bed, erosion chains et bed markers assessing the active area of the bed during sediment transport events. Data show an intense and complex activity of bedload transport while the bed remained relatively stable. Our hypothesis to explain these dynamics is related to the dilatation and contraction of the sediments composing the river bed during floods.
06/05/2010 @ 12:15 room GC A3 30

Creep in bulk materials in the moist environment: a chemo-mechanical coupling

Prof. Tomasz Hueckel, Duke University
20/05/2010 @ 18:00 room CO 1

Discounting the Environment - Landolt & Cie Public Lectures

Prof. Sir Partha Dasgupta, Univ. Cambridge, winner of the 2002 Volvo Environment Prize

Discussions on the economics of sustainable development invariably move to debates on our obligations to future generations. Choice of the rates with which to discount the future environmental costs and benefits of current decisions is central to those debates. Prof. Dasgupta will present the ethical framework that has informed recent discussions on the subject by considering the economics of climate change. He will identify the source of the vigorous disagreements we have witnessed in the recent literature and then argue that the ethical framework that has been adopted by the protagonists is misconceived. Prof. Dasgupta will suggest that sustainable development doesn't so much involve an ethical problem facing the generations as it involves bargaining among contemporaries. Sir Partha Dasgupta is the Frank Ramsey Professor of Economics at the University of Cambridge, Fellow of St John's College, Cambridge, and Professor of Environmental and Development Economics at the University of Manchester. Professor Dasgupta is, among others, a Fellow of the Econometric Society, of the Royal Society, Member of the Pontifical Academy of Social Sciences, was co-winner of the 2002 Volvo Environment Prize, and was named Knight Bachelor by Her Majesty Queen Elizabeth II in her Birthday Honours List in 2002 for "services to economics". His research interests have covered welfare and development economics, the economics of technological change, population, environmental and resource economics, the theory of games, and the economics of undernutrition.
23/09/2010 @ 12:15 room GC A331

Advances in laminated glass for structural applications

Prof. Jan Belis from Ghent University
30/09/2010 @ 12:15 room GC A3 31

Developments in Microscopic Traffic Flow Theory

Prof. Alex Skabardonis, UC Berkeley

In this talk we discuss recent developments in microscopic traffic flow theory based on extensive analysis of vehicle trajectory data collected as part of the Next Generation Simulation (NGSIM) project, sponsored by the US Federal Highway Administration. First, we present a new behavioral algorithm for oversaturated freeway flow that can be readily used in microscopic simulation models. The proposed algorithm is an integrated car-following and lane changing modeling framework that is consistent with the kinematic wave theory. The algorithm can explicitly model mandatory and discretionary lane changing, including cooperation during lane changing. Also, the proposed algorithm accounts for the relaxation process following lane changing. Next, we propose an asymmetric traffic theory, and explain the frequently observed stop-and-go traffic phenomenon in light of the developed theory.
Alexander Skabardonis, Ph.D. is an internationally recognized expert in traffic flow theory and models, traffic management and control systems, design, operation and analysis of transportation facilities, intelligent transportation systems (ITS), and energy and environmental impacts of transportation. He is a Professor at the University of California, Berkeley, where he also serves as the Director of California PATH, a statewide ITS research center. He is a member of the Transportation Research Board (TRB), Freeway Operations, Traffic Flow Theory and Highway Capacity and Quality of Service Committees. He serves on the editorial board of the Intelligent Transportation Systems Journal, and as a reviewer for several archival journals in transportation.
14/10/2010 @ 12:15 room GC A3 31

Understanding individual mobility using GPS data

Prof. Armando Bazzani, Un. of Bologna

Recent studies have pointed out the complexity of human mobility and the necessity of understanding the individual mobility demand to perform a mobility governance. In Italy a relevant percentage of vehicle population is equipped by a GPS system for insurance reason and the origin and destination of each trip is recorded in a data base. We have analyzed the GPS data of the whole Emilia-Romanga region recorder during the November 2008 to look for generic scaling laws that characterize human mobility. We propose the existence of an "mobility energy" that determines the trip length distribution. We also reconstruct the mobility network from experimental data and we show as the mobility demand is a mixed of an origin-destination systematic mobility and a random asystematic mobility which produces a diffusion behavior in the network. We finally consider the possibility of classifying the different individuals according to the properties of their mobility networks.
Prof. Bazzani is member of the group of Physics of Complex Systems (www.physycom.unibo.it) at the Physics Department of the Bologna University and he coordinates some research projects in the Physics of the City Laboratory. He is responsible of the INFN theory project BO41 on physical applications of dynamical systems theory. The main research interests of Prof. Bazzani concern the study of dynamical models relevant for social and biological systems., among others, the applications of dynamical systems theory to neuronal networks and evolution models, and the emergent properties of an automata gas (i.e. a statistical systems of cognitive particles) studied for the applications to modeling urban mobility.
18/10/2010 @ 12:15 room GC F1 11

Punching Shear Resistance of Slab-Column Connections under Monotonic and Reversed Cyclic Loading

Prof. Gustavo J. Parra-Montesinos, Univ. of Michigan

Flat plates or flat slabs are commonly used in reinforced concrete framed construction. The achievement of a uniform floor bottom surface and greater clear story height compared to regular beam-column frames makes this type of construction economical and architecturally appealing. The lack of beams, however, requires that special attention be paid to preventing punching shear failures in the connections between the slab and the supporting columns. For several decades the use of drop panels or capitals was the preferred option to increase the punching shear strength of slab-column connections. In the past few years, however, solutions that do not require a change in the slab thickness have become popular, such as the use of shear reinforcement in the form of headed studs. Results from experimental research aimed at evaluating the effectiveness of two types of shear reinforcement in slab-column connections, headed studs and hooked steel fibers, will be presented. (...) Test results indicate that hooked steel fibers are effective as punching shear reinforcement in slab-column connections. Under monotonically increased load, the use of fiber reinforcement in the connection region led to a substantial increase in shear strength with the potential of changing the slab failure mode from brittle shear failure to ductile flexural failure. Contrary to observations made by other researchers, the use of shear stud reinforcement did not lead to an increase in connection shear strength compared to slabs without shear reinforcement. After punching, however, the slabs with headed studs exhibited a relatively gradual strength decay compared to a nearly total loss of strength in the slabs without shear reinforcement. Under a gravity shear ratio of ½ and bi-axial lateral displacement reversals, the use of fiber reinforcement allowed the slab to exhibit substantial flexural yielding prior to failing in punching shear, which occurred at drifts on the order of 3%. On the other hand, the slab-column connection with shear stud reinforcement failed in punching shear at a drift of approximately 1.6%. This failure was characterized by a breakout failure of the concrete engaged by the second line of studs, accompanied by severe bending of the rail supporting the studs.
21/10/2010 @ 12:15 room GC A3 31

An Analysis of HOV Lanes: Their Impact on Traffic

Dr Monica Menendez, ETHZ

Dr. Menendez developed a simple model for car-following with lane-changing that matches field data with considerable accuracy. The model is based only on physical principles and requires few parameters. It uses very simple microscopic rules to reproduce the aggregate characteristics of traffic. The movement of any vehicle is only constrained by its mechanical properties, driver comfort, and safety. The model is proved to be fail-safe, e.g., it has no crashes independently of the deceleration bounds. The final product is used in micro-simulations to study the impact that High Occupancy Vehicle (HOV) lanes have on traffic. HOV lanes are restricted-use freeway lanes reserved for vehicles with more than a predetermined number of occupants. Dr. Menendez's research examines the physics of HOV lanes placed on median lanes, with open access everywhere. HOV lanes can affect the capacity of freeway bottlenecks through both an under-utilization effect and a disruption effect. However, under some circumstances, they can actually increase the flow of the adjacent general purpose lanes through a smoothing effect. This research suggests simple strategies to take advantage of that smoothing effect and increase the efficiency of the HOV lanes in general.
Monica Menendez recently joined ETH Zurich as the Director of the Research Group "Traffic Engineering." Prior to that, she was a Management Consultant at Bain & Company's San Francisco office. She joined Bain after receiving a PhD and an MS in Civil and Environmental Engineering from the University of California, Berkeley in 2006. Her research interests include traffic flow theory and operations, sustainable transportation, and logistics.
04/11/2010 @ 12:15 room GC A331

Fluid mechanics challenges in the energy/environment nexus: Insights gained via numerical simulation

Prof. Fotis Sotiropoulos, University of Minnesota

The need for restoring degrading waterways coupled with the increasing demand for clean and renewable energy from wind and water resources have given rise to challenging fluid mechanics problems in the energy-environment nexus. Simulation-based research is in many cases the only viable approach for tackling such problems, which pose a formidable challenge to even the most advanced numerical methods available today. Flows of interest take place in arbitrarily complex multi-connected domains with moving, rigid or flexible immersed bodies interacting with the flow (fluid/structure interaction); involve physical phenomena coupled across disparate scales; occur over a broad range of Reynolds numbers and flow regimes; and are dominated by coherent vortical structures. This talk will present a novel and versatile computational fluid dynamics framework for simulating such flows that integrates immersed boundary methods with curvilinear, overset grids, features accurate and robust fluid-structure interaction algorithms, and is capable of carrying out coherent-structure-resolving simulations of turbulent flows in arbitrarily complex domains with dynamically evolving boundaries. The potential of the method will be demonstrated by discussing applications to study: 1) the hydrodynamics of aquatic swimming; 2) turbulent flow and transport in natural streams; and 3) hydrokinetic and wind turbine flows. Future grand challenges and opportunities for tackling a wide range of fluid mechanics problems in the energy-environment nexus via simulation-based research will also be discussed.
11/11/2010 @ 12:15 room GC A3 31

Chilean Design and the Mw = 8.8 Feb 27 2010 Chile Earthquake

Prof. Ruben L. Boroschek

The Feb 27, 2010 Chile earthquake is one of the largest in history and the first to be recorded with strong motion instrument at close distance. The earthquake affected an area of approximately 160.000 square kilometers causing nearly 550 deaths, severe damage in more than 200.000 houses and a severe tsunami. Engineering structure in general responded well, nevertheless several lessons have to be learned. The talk will present the main shaking characteristics derived from the strong motion records and the main damage that suffered engineered buildings and bridges. Also a general description of Chilean design and the new trends that it will be followed considering the response of the infrastructure during this severe event.
Prof. Boroschek graduated in Structural Engineering at University of California Berkeley. He is now Associate Professor at the University of Chile, and Vice-President of the Chilean Seismology and Earthquake Engineering Association. His main research interests are: Strong motion simulation, Experimental Dynamic of Structures, Structural Health Monitoring, Vulnerability Assessment of Critical Facilities, Base Isolation and Passive Energy Dissipation, Damage Assessment of Structure, Health Care Facilities Vulnerability Studies and Mitigation (functional protection).
18/11/2010 @ 12:15 room GC A331

Assessment of regeneration projects in urban areas of environmental interest: a stated choice approach to estimate use and quasi-option values

Prof. Elisabetta Cherchi, DTU, Denmark

A specific problem inherent in urban planning in areas of environmental interest is that problems can occur when ideas are effectively turned into action, and it is possible that eventually the implementation is not consistent with the plan. If the development of the project produces undesired effects, there might be an irreversible loss of environmental values. To evaluate the quasi-option values associated with environmental renewal projects in urban areas and to elicit inter-temporal preference over projects with different time spans. We adopt an attribute-based stated choice approach to elicit preferences about three planning alternatives for environmental renewal of the corridor along the beach front, including car access restrictions. Since such projects involve some uncertainty and irreversibility, the quasi-option values associated with project development is estimated. Results show a great sensitivity towards environmental renewal, and this varies significantly with the characteristics of each individual. However, individuals show a strong preference for a mild environmental renovation rather than an extreme ecological scenario. Results also show that a more prudent development strategy is valued at about four times greater than a procedure that provides a greater chance of an undesired outcome.
Elisabetta Cherchi has recently joined DTU Transport as Associated Professor. Previously she has been Lecturer in Econometrics Methods for Transportation at the Department of Territorial Engineering, Università de Cagliari (Italy), Associate Lecturer at the Transport Research Centre, Universidad Politecnica de Madrid (Spain) and Researcher at CTS, Imperial College (UK) where she is still Honorary Researcher. She has collaborated for almost 15 years with Pontificia Universidad Católica de Chile, and more recently with Maryland University. Her main research interest is in the demand modelling of consumer behaviour, with particular reference to discrete choice analysis, microeconomic derivation of behavioural models and project evaluation. She is member of the Editorial Board of Transportation Research part B and Transportation, and Board Member of the International Association of Behavioural Research (IATBR). Elisabetta Cherchi has been also involved as consultant in more that 25 transport projects at local, national and international level.
25/11/2010 @ 12:15 room GC A3 31

How do Humans Drive a Car? - Modelling Accelerations and Discrete-Choice Situations in Freeway and City Traffic

Prof. Martin Treiber, TU Dresden

For an experienced human driver, the "operational" driving tasks seem to be easy: After all, one usually has no problem to accelerate or brake in order to reach a desired speed, or keeping sufficient space to avoid crashes. The same applies when deciding if it is safe to enter a priority road, to overtake, or to pass a "yellow" traffic light that will be "red" in the next few seconds. When attempting to cast this driving behaviour into equations of a mathematical model, however, one feels more like a driving beginner: It is all but easy to find models that reproduce the human driving behaviour! In this talk, I will discuss "car-following models" for the accelerations, and "decision models" for discrete-choice situations such as lane changing or entering a priority road. The models can be parametrized to represent driving behaviour such as timid/aggressive, experienced/unexperienced, or fast vs. relaxed. One model has been implemented into a semi-automatic car, and the author has been driven with it on public freeways. I will report about this experience. Fially, by means of simulations, I will show how external measures (such as speed limits), and the drivers themselves influence the probability of traffic breakdown and the development of stop-and-go traffic.
Martin Treiber [Dr. rer. nat., 1996, University of Bayreuth, Germany] is at the Departement of Transport and Traffic Sciences, Dresden University of Technology, Germany. He teaches traffic modelling & simulation, econometrics, and statistics. His research interests include vehicular traffic dynamics and modelling, traffic data analysis & state estimation, and driver ass istance systems. This includes several public and commercial projects. He developed a ra nge of simple yet realistic traffic models and runs the popular web site www.traffic-simulation.de . He has over 60 peer-reviewed publications and currently is writing a textbo ok on traffic modeling and simulation.
02/12/2010 @ 12:15 room GR A3 30

! CANCELLED ! Recent advances in multi-scale computational homogenization

Prof. Marc Geers, Eindhoven University of Technology

Considerable progress had been made in bridging the mechanics of materials to other disciplines, e.g. downscaling to the field of materials science or upscaling to the field of structural engineering. The steady progress essentially results from the research efforts invested in multi-scale modelling in general, whereby a focus on multi-disciplinary aspects naturally arises. There are various ways to classify multi-scale methods in a general setting. In this presentation, attention is restricted to a particular method that falls in the category of homogenization methods based on integration over short length scales. This category of methods is also called "coarse graining" in the physics community. Among the various homogenization techniques proposed, a computational homogenization scheme is probably one of the most accurate techniques in upscaling the nonlinear behaviour of a well-characterized microstructure. This method is essentially based on the construction of a micro-scale boundary value problem, used to determine the local governing behaviour at the macro scale. In case the macro scale boundary value problem is solved simultaneously, a fully nested solution of two boundary value problems is obtained, one at each scale. Though computationally expensive, the procedures developed allow to assess the macroscopic influence of microstructural parameters in a rather straightforward manner. Several topics will be addressed: _ First-order computational homogenization: historical overview and key principles _ Second-order computational homogenization: how to incorporate the size of the underlying microstructure? _ Continuous-discontinuous multi-scale approach for localization problems: the problem and the solution inspired by embedded localization bands. _ Multi-physics and coupled problems: the heat conduction problem & thermo-mechanically coupled computational homogenization _ Thin structures: shells and beams, how to handle flat structures with a complex through-thickness architecture? _ Computational homogenization towards cohesive zones.
The most important issues are commented for each of the topics addressed, with a particular emphasis on the applicability, and possible limitations of each. The presentation concludes with some general remarks on the added value of computational homogenization techniques as stand-alone tools or in development of alternative multi-scale methods. Finally, some open issues and challenges are summarized.
09/12/2010 @ 12:15 room GC A331

A Unified Effective Stress Concept for Variably-Saturated Soil

Prof. Ning Lu, Colorado School of Mines

A unified effective stress concept based on the suction stress characteristic curve (SSCC) for variably-saturated soil is discussed. Particle-scale equilibrium analyses are employed to distinguish three types of soil interparticle forces: (1) active forces transmitted through the soil grains (Terzaghi's); (2) active forces at or near interparticle contacts (physicochemical); and (3) passive, or counterbalancing, forces at or near interparticle contacts (Born's and steric). It is proposed that the second type of forces, which includes physicochemical forces, cementation forces, surface tension, and the force arising from negative pore-water pressure, can be conceptually combined into a macroscopic stress called suction stress. Suction stress characteristically depends on degree of saturation, or soil suction, thus paralleling well-established concept of the soil-water characteristic curve in soil physics. The existence and behavior of the SSCC are experimentally validated by considering unsaturated shear strength and volumetric behavior data for a variety of soil types in the literature. The characteristics and practical determination of the SSCC are demonstrated. A closed form equation for predicting the suction stress for all soils is found. A case study of shallow landslide initiation induced by heavy rainfalls illustrates that variation in suction stress can well reconcile the spatial and temporal characteristics of the event. Suction stress provides a potentially simple and practical means to describe the state of stress in unsaturated soil.
Ning Lu is professor of engineering at Colorado School of Mines and the director of the joint CSM/USGS Geotechnical Research Laboratory. He obtained a PhD degree in engineering science from the Johns Hopkins University in 1991. Prior to joining Colorado School of Mines in 1997, he worked at Disposal Safety Inc., at the US Geological Survey, and as an assistant professor at Louisiana State University. His primary research interests are to seek common threads among soil physical phenomena including fluid flow, chemical flow, heat transfer, stress, and deformation, and to build bridges from atomic-scale potentials to particle-scale forces and engineering-scale stresses in soil. He is the senior author of the text book "Unsaturated Soil Mechanics" (John Wiley and Sons), recipient ASCE's Normal Medal (2007) and J. James Croes Medal (2010). He will be the Shimizu Visiting Professor at Stanford University in 2011.
13/12/2010 @ 16:15 room GR A3 31

River restoration - Complex hydrological and ecological changes: The RECORD-Project

Schirmer, Mario (EAWAG)

Restoration is an essential means to enhance the dynamic stability of rivers while correspondingly improving habitat diversity and variability and lowering long-term maintenance expenditures. Although the number of restoration projects has increased in recent years, scientific understanding is still limited with regards to the underlying principles determining how hydromorphological variability in restored river corridors relates to ecosystem functioning, biodiversity and (ground)water quality. In order to cope with the challenges of river restoration in a successful and efficient way, we need to increase our mechanistic understanding of the coupled hydrological and ecological processes in near-river corridors. Limitations in scientific advancement in these areas have especially been impaired by discipline-specific research rather than a multi-disciplinary endeavor that collaboratively investigates cause-and-effect relationships and re-examines historical assumptions and approaches. In the multi-disciplinary RECORD Project (Assessment and Modeling of Coupled Ecological and Hydrological Dynamics in the Restored Corridor of a River (Restored Corridor Dynamics)), we investigated coupled hydrological and ecological dynamics in a channelized and restored river section in northeast Switzerland by synthesizing physical, chemical, and biological experiments and modeling.
16/12/2010 @ 12:15 room GC A3 31

Punching shear and shear resistance of high performance fibre reinforced concrete

Prof. René Suter, University of applied sciences Fribourg

Modern admixtures as well as the addition of steel fibres allow producing concretes with exceptional mechanical rheological and durability characteristics. These high performance fibre reinforced concretes (HPFRC) are perfectly adapted to the design of new and innovative constructions. Currently in practice the use of high performance concretes is still limited to isolated cases despite the highly attractive characteristics of this material. The principal reasons are a poor knowledge on the behaviour of structural HPFRC elements and the lack of adequate design rules. In order to contribute to a better knowledge on the structural behaviour of these concretes theoretical and experimental studies were carried out at University of applied sciences in Fribourg. This presentation will discuss the studies of shear behaviour of post-tensioned concrete beams and punching shear capacity of thin concrete slabs. Full scale tests were carried out on seven precast and post-tensioned TT beams and on eight rectangular beams in order to analyse the contribution of steel fibres on the shear capacity. These tests showed that the addition of steel fibres increases the shear capacity by 10 % to 40%. According to these results it will be possible to replace stirrups by an adequate percentage of fibres. Load tests were also carried out on twenty HPFRC slabs according to three parameters: the quantity of fibres the reinforcement ratio and the post-tensioning level. These tests highlighted the contribution of steel fibres on punching shear capacity which increases by 20% to 70 %. They also showed that the punching shear capacity is inversely proportional to the rotation of the slab. That means the more the reinforcement ratio or the post-tensioning level are important the more the risk of a failure by punching shear becomes determinant. The numerical analysis on the behaviour of the slabs is based on the failure criterion developed by Muttoni. Actually we are working on adapting this failure criterion for HPFRC slabs in order to establish directives for dimensioning.
09/02/2011 @ 07:00 room GC C3 30

Recent advances in multi-scale computational homogenization

Prof. Marc Geers, Eindhoven University of Technology

Considerable progress had been made in bridging the mechanics of materials to other disciplines, e.g. downscaling to the field of materials science or upscaling to the field of structural engineering. The steady progress essentially results from the research efforts invested in multi-scale modelling in general, whereby a focus on multi-disciplinary aspects naturally arises. There are various ways to classify multi-scale methods in a general setting. In this presentation, attention is restricted to a particular method that falls in the category of homogenization methods based on integration over short length scales. This category of methods is also called "coarse graining" in the physics community. Among the various homogenization techniques proposed, a computational homogenization scheme is probably one of the most accurate techniques in upscaling the nonlinear behaviour of a well-characterized microstructure. This method is essentially based on the construction of a micro-scale boundary value problem, used to determine the local governing behaviour at the macro scale. In case the macro scale boundary value problem is solved simultaneously, a fully nested solution of two boundary value problems is obtained, one at each scale. Though computationally expensive, the procedures developed allow to assess the macroscopic influence of microstructural parameters in a rather straightforward manner. Several topics will be addressed: _ First-order computational homogenization: historical overview and key principles _ Second-order computational homogenization: how to incorporate the size of the underlying microstructure? _ Continuous-discontinuous multi-scale approach for localization problems: the problem and the solution inspired by embedded localization bands. _ Multi-physics and coupled problems: the heat conduction problem & thermo-mechanically coupled computational homogenization _ Thin structures: shells and beams, how to handle flat structures with a complex through-thickness architecture? _ Computational homogenization towards cohesive zones.
The most important issues are commented for each of the topics addressed, with a particular emphasis on the applicability, and possible limitations of each. The presentation concludes with some general remarks on the added value of computational homogenization techniques as stand-alone tools or in development of alternative multi-scale methods. Finally, some open issues and challenges are summarized.
24/02/2011 @ 12:15 room GC C3 30

Numerical simulations of impact on a concrete structure: the researcher's and engineer's point of view

Fabrice Gatuingt, Ecole Normale Supérieure de Cachan

Abstract: Transient loading has always been an important feature to take into account for the design of concrete structures. This transient loading can be due to an explosion, a mine blast or an accidental collision of cars, trains or airplanes with the structure (since the 9/11 events commercial airplanes have also to be taken into account). In particular for structures that involve public safety, they have to be designed to resist not only the static loading but also the dynamic loading produced by these extreme conditions. Different approaches can be used to tackle this problem. One could assume that a simplified method based on the Riera's model and a simple description of the structure, which has proved its efficiency in the past, is always able to describe this new type of loading. On the other hand, engineers could postulate that the current numerical capabilities could lead to a better description of the physical phenomena that occur during the impact and therefore could help the design optimized structures.
This presentation will show, through experimental data, the behavior of the concrete under this kind of loading and how it affects the constitute equations. In a second part we will focus on the OECD benchmark IRIS_2010 that was used to test the accuracy of the different descriptions and approaches of this kind of problem.
Bio: Fabrice Gatuingt is an assistant professor in the Civil Engineering Department at the Ecole Normale Supérieure de Cachan. He obtained in 1999 a PhD in Civil Engineering at the LMT Cachan. In 2000, he held a post-doctoral position at the CEA Saclay to study the numerical methods to represent localized cracks. Before his sabbatical stay in Lausanne he was the head of the Civil Engineering Department. His research activities are mainly centered on the development of concrete constitutive laws for dynamic loading and the numerical methods associated with them.
09/03/2011 @ 12:15 room GC B3 30

Manufacturing as a Subset of Construction: CEPM Research and Implications for Applied Operations Research

Dr. William J. O’Brien, Associate Professor, University of Texas at Austin

Construction activities generally comprise the range of manufacturing production disciplines in a predictable yet unique agglomeration per project. As such, the management of construction projects represents one of the most complex endeavors undertaken by mankind. Management of on-site activities in constrained spaces together with sourcing and transporting discrete units of capacity across multiple supply chains is a task that is fraught with coordination challenges that often lead to cost and schedule overruns. Established coordination procedures also restrict deployment of new approaches. Limiting discussion to production planning and operations, there are a range of optimization techniques that are potentially applicable to construction projects. However, most of these are not used. A review of construction challenges is presented along with current research related to traditional operations research solutions. The potential for application of advanced methods such as risk analysis with unstable and conditional underlying probabilities and multi-scale modeling is discussed. Based on the likelihood of improved data availability from the sensed environment that supports sophisticated analyses, we close with a vision for a decision support environment that blends optimization, scenario analysis, and visualization.
About the Speaker: Dr. William J. O'Brien focuses his professional efforts on improving collaboration and coordination among firms in the design and construction industry. Dr. O'Brien is an expert on construction supply chain management and electronic collaboration, where he conducts research, teaches and consults on both systems design and implementation issues. He was the lead editor on the recently published Construction Supply Chain Management Handbook (CRC Press). He is the author or co-author of over 100 journal articles, book chapters, conference papers, and technical reports. Dr. O'Brien is currently an Associate Professor in the Department of Civil, Architectural, and Environmental Engineering in the Cockrell School of Engineering at the University of Texas at Austin. Dr. O'Brien is a Specialty Editor for the ASCE Journal of Computing in Civil Engineering and an Associate Editor for Advanced Engineering Informatics. Dr. O'Brien holds a Ph.D. and a M.S. degree in Civil Engineering and a M.S. degree in Engineering-Economic Systems from Stanford University.
17/03/2011 @ 12:15 room GC C3 30

Coupling Schemes for Transient Fluid/Structure Interaction Simulations

Philippe H. Geubell, Department of Aerospace Engineering, University of Illinois

Abstract This presentation summarizes the development of a novel numerical treatment of coupled multiphysics problems, with emphasis on the simulation of transient fluid/structure interaction (FSI) events, such as the propagation of shocks and blast waves along deformable media, structural-acoustic coupling, flutter instability problems and aeroelasticity-driven failure events in solid propellant rockets. The talk will focus primarily on the development of an accurate scheme used to transfer fluid-induced loads across non-matching discretized interfaces and its impact on the accuracy of the coupled solution. We will present the results of a detailed comparative study between the proposed method and existing load transfer schemes. This comparative assessment is based on a set of FSI applications of increasing complexity involving flat and curved fluid interfaces. The last part of the presentation will focus on the on-going modeling activities in the area of structural/acoustic coupling.
Short Bio Originally from Belgium, Philippe Geubelle got his Ph.D. in Aeronautics at Caltech in 1993. After postdoc at Harvard, he joined the University of Illinois in 1995, where he is currently professor and associate head in the Department of Aerospace Engineering, with joint appointments in Mechanical Science and Engineering, and Civil and Environmental Engineering. He is also serving as Director of the Illinois Space Grant Consortium, a NASA-sponsored higher-education program. His research interests pertain to the theoretical and numerical treatment of complex problems in solid mechanics, and, in particular, of quasi-static and dynamic fracture mechanics, multiscale modeling of heterogeneous, layered and MEMS materials, composite manufacturing processes and computational design of novel biomimetic materials. Other research activities involve computational aeroelasticity and parallel programming.
24/03/2011 @ 12:15 room GC C3 30

Highway Traffic Stability

Prof. R.E. Wilson, University of Southampton

Most drivers will recognize the scenario: you are making steady progress along the motorway when suddenly you come to a sudden halt at the tail end of a lengthy queue of traffic. When you move off again you look for the cause of the jam but there isn't one. No accident damaged cars no breakdown no dead animal and no debris strewn on the road. So what caused everyone to stop?" RAC news release (2005)
The (by now well-known) answer is that such "phantom traffic jams" exist as waves that propagate upstream (opposite to the driving direction) - so that the vast majority of individuals do not observe the instant at which the jam was created - yet what exactly goes on at that instant is still a matter of debate. In this talk I'll give an overview of empirical data and models to describe such spatiotemporal patterns. The key property we need is instability: and using the framework of car-following (CF) models I'll show how different sorts of linear (convective and absolute) and nonlinear instability can be used to explain the empirical patterns.
References:
R.E. Wilson Mechanisms for spatio-temporal pattern formation in highway traffic models. Philosophical Transactions of the Royal Society: part A 366:2017-2032 2008.
J.A. Ward and R.E. Wilson. Criteria for convective versus absolute string instability in car-following models. Proceedings of the Royal Society: part A 2011 in press. Published on-line before print doi:10.1098/rspa.2010.0437
Biography:
Eddie Wilson is a Mathematician by background with MA and DPhil degrees from Oxford. In 2000 he secured his first Faculty position in the Department of Engineering Mathematics at the University of Bristol (England) - where he later became Reader. During his time in Bristol he worked on the mathematical modelling of a variety of engineering applications but with an increasing focus in road transport problems. In 2007 he was awarded the prestigious EPSRC Advanced Research Fellowship and in 2010 he moved to the Transportation Research Group at the University of Southampton where he is Professor of Modelling and Simulation.
31/03/2011 @ 12:15 room GC C3 30

Recent advances in multi-scale computational homogenization

Prof. Marc Geers, Eindhoven University of Technology

Considerable progress had been made in bridging the mechanics of materials to other disciplines e.g. downscaling to the field of materials science or upscaling to the field of structural engineering. The steady progress essentially results from the research efforts invested in multi-scale modelling in general whereby a focus on multi-disciplinary aspects naturally arises. There are various ways to classify multi-scale methods in a general setting. In this presentation attention is restricted to a particular method that falls in the category of homogenization methods based on integration over short length scales. This category of methods is also called "coarse graining" in the physics community. Among the various homogenization techniques proposed a computational homogenization scheme is probably one of the most accurate techniques in upscaling the nonlinear behaviour of a well-characterized microstructure. This method is essentially based on the construction of a micro-scale boundary value problem used to determine the local governing behaviour at the macro scale. In case the macro scale boundary value problem is solved simultaneously a fully nested solution of two boundary value problems is obtained one at each scale. Though computationally expensive the procedures developed allow to assess the macroscopic influence of microstructural parameters in a rather straightforward manner. Several topics will be addressed: _ First-order computational homogenization: historical overview and key principles _ Second-order computational homogenization: how to incorporate the size of the underlying microstructure? _ Continuous-discontinuous multi-scale approach for localization problems: the problem and the solution inspired by embedded localization bands. _ Multi-physics and coupled problems: the heat conduction problem & thermo-mechanically coupled computational homogenization _ Thin structures: shells and beams how to handle flat structures with a complex through-thickness architecture? _ Computational homogenization towards cohesive zones.
The most important issues are commented for each of the topics addressed with a particular emphasis on the applicability and possible limitations of each. The presentation concludes with some general remarks on the added value of computational homogenization techniques as stand-alone tools or in development of alternative multi-scale methods. Finally some open issues and challenges are summarized.
14/04/2011 @ 12:15 room GC C3 30

Estimating travel times from abundant data

Prof. Dr. Benjamin Heydecker

Contemporary Intelligent Transport Systems (ITS) provide abundant data that can be used to monitor, manage and control transport systems. However, the quality of the data is in general not known and the volume is too great for record-by-record investigation to be a practical proposition. In this seminar, we will see how statistical analysis can be applied to filter a dataset by treating it as a whole by fitting a discrete mixture of statistical distributions We then explore how this reflects on the individual observations. To illustrate use of this approach, it is applied to a certain dataset of travel times that is generated by matching time-stamped records of vehicle registration plates from automatic number-plate recognition (ANPR) system. Analysis of the mixed distribution leads to estimates of the error rate of the data collection methods, and by eliminating the corresponding component the travel time distribution can be estimated. This has dual importance: it shows how distributions of travel times can be extracted from ITS of this kind to provide estimates for direct use, and beyond that it shows how statistical analysis can be applied to manage the abundant data streams that we now receive from ITS.
About the speaker
Benjamin Heydecker is the Head of Centre for Transport Studies and Professor of Transport Studies at University College, London. His research lies in developing and applying mathematical and statistical analyses in transport studies. He has pursued this along three broad themes within the field: Traffic management and control, including real-time information and control systems; Transport safety, including the analysis and interpretation of road accident data; and Transport planning methods, including dynamic transport modelling. The interrelationships between these themes, and between each of them and methodologies for estimation, design and management are of special interest to him. He is a fellow of the Institution of Mathematics and its Applications and of the Royal Statistical Society. Heydecker is involved in the EU FP7 Network of Excellence for Advanced Road Cooperative Traffic Management in the Information Society (NEARCTIS), where he is investigating the research agenda for developments in ITS to promote a wide range of potential benefits.
05/05/2011 @ 12:15 room GC C3 30

Fire in tunnels: steps towards a real time solution

Prof. Bernhard Schrefler

The availability of an efficient tool for simulation of a fire scenario in a tunnel is of paramount importance for fire safety management in emergency situations, for training of fire brigades prior to emergency cases in order to be able take the right decisions when needed and to evaluate measures geared to increase the resistance of existing tunnel vaults against spalling. We have developed such a tool which takes the thermal fluid-structural coupling in a tunnel fire fully into account. The simulation of a realistic fire scenario is still a time consuming task and measures have to be taken to reduce the computing time. It is neither possible to disregard the enormous heat sink the tunnel vault represents with its phase changes and chemical reactions nor to simplify the physical model. Up to now we have chosen a 3D-2D coupling strategy where the thermally driven CFD part is solved in a three dimensional cavity and the concrete behaviour is solved on 2D sections normal to the tunnel axis, at appropriate intervals. The aim of our current research effort is twofold: realize a true 3D-3D coupling and reduce drastically the solution time. The way for achieving this is through adoption of an extremely fast equation solver which can achieve a speed-up of up to 3600 times and the adoption of the Proper Generalized Decomposition PDG for a fast 3D solution of the problem of heated concrete. Steps in this direction as well as the general model will be shown.
Dr. Bernhard Schrefler is professor of Structural Mechanics at the University of Padua and Secretary General of CISM. He obtained his Ph.D. and D.Sc. at the University of Wales. He received honorary doctorates from the St.Petersburg State Technical University, from the University of Technology in Lodz, from the University of Wales-Swansea, from the Leibniz University of Hanover, from the Russian Academy of Sciences and from the Ecole Normale Superieure, He is recipient of the Computational Mechanics Award, the IACM Award, the Biot Medal of ASCE and the Euler Medal of ECCOMAS. He has published close to 200 papers in refereed Journals on structural engineering, soil mechanics, environmental mechanics, and biomechanics and on technology for nuclear fusion, and has written or edited 33 books. His main research interests are in multi-scale analysis and porous media mechanics including environmental geomechanics.
12/05/2011 @ 18:00 room Forum Rolex Learning Center

Structures en bambou

Simon Velez, architecte colombien

Les tiges de bambous offrent une résistance exceptionnelle pour un poids réduit (tige creuse) le bambou pouvant ainsi concurrencer l'acier ou le béton. L'architecture en bambou a été révolutionnée par le recours au mortier et aux boulons pour l'assemblage une technique mise au point par Simón Vélez et Marcelo Villegas il y a vingt ans. Cette méthode consiste à remplir avec du mortier une partie des tiges entre deux noeuds puis à les fixer entre elles avec des boulons. On peut ainsi regrouper plusieurs tiges pour constituer des piles dignes d'une cathédrale et des travées de plus de 50 mètres de long. Le dernier projet de Vélez est une résidence écologique de 130 chambres en Chine mais il a déjà construit des structures autrement plus musclées en Colombie dont des ponts d'énormes toits d'usines des stades et des marchés couverts. Fils et petit-fils d'architectes Simon Velez est né en 1949 à Manizalez Colombie. Dans son processus créatif Simon Vélez agit en pragmatique à la fois audacieux et attentif aux possibilités du matériau. Il se montre également inventif avec des bois d'autres espèces disponibles en abondance localement et souvent dédaignées ; il n'hésite pas à recourir à l'acier mais se concentre alors sur des fournitures modestes voire élémentaires comme l'acier d'armature ou les tubes de forage. S'il se défend d'en faire une monomanie il s'est beaucoup concentré sur le bambou et démontre que ce matériau est efficace et esthétique pour le bâtiment avec des implications profondes pour le développement social et l'environnement. Simón Vélez est reconnu sur la scène internationale et a réalisé des projets aux Etats-Unis en Allemagne en France au Brésil au Mexique en Jamaïque à Panama en Equateur en Inde et en Chine. Il a été invité pendant quatre ans consécutifs au Vitra Design Museum et au Centre George Pompidou pour y conduire des ateliers. En 2009 Simon Velez a reçu le Grand Prix de la Fondation Prince Claus. Ce prix prestigieux salue sa précieuse contribution à des pratiques architecturales durables mais également son effort dans des projets de développement durable et de développement social et son intérêt soutenu à l'élaboration de relations entre culture et nature.
13/05/2011 @ 12:15 room GC C3 30

Modular Construction of Residential Buildings

Prof. Mark Lawson, University of Surrey, UK

During the last 10 years there has been great interest in the use of "off-site" manufacturing technologies in construction. One of these "off-site" methods is modular or 3-dimensional construction which has found markets in residential buildings hotels medical and educational buildings. In the UK it is estimated that 8000 modules are produced per year for use in permanent buildings (and many more in temporary buildings) and there are 5 main manufacturers. In Japan up to 100 000 modules were manufactured for use in housing.
There are two generic forms of modular construction in steel - one in which the modules are manufactured with light steel walls and floors that resist vertical and horizontal loads and one in which corner posts and edge beams of the modules provide the primary structure. In the first case the walls of the modules form the enclosed space and in the second case open-sided modules can be manufactured for use in schools hospitals etc. Modules can also be built in precast concrete and in wood for some applications.
The economic and sustainability argument for modular construction will be presented which is based on more efficient use of materials less waste higher quality and a faster and less disruptive construction process. Nevertheless the investment in an advanced manufacturing process can be relatively high which has to be balanced by achieving an economy of scale in manufacture. The overall costs of modular construction will be reviewed. Low energy design and use of renewable energy technologies will also be reviewed in the context of modular construction.
Bio: Mark is a graduate of Imperial College London and prepared his Doctorate thesis under Professor Eric Bryan at the University of Salford on the "Stressed Skin Design of Steel Folded Plate Roofs". He worked for Ove Arup and partners where he became a chartered civil and structural engineer in the UK and also a member of the American Society of Civil Engineers. In 1981 he was an assistant at ICOM for 6 months and worked with Michel Crisinel on composite decking in composite construction. In 1987 he joined the Steel Construction Institute (SCI) in Ascot south west of London and has prepared over 30 SCI publications including many on light steel and modular construction. In 2004 he became Professor of Construction Systems at the University of Surrey which is a part-time role and he also is a technical consultant to SCI.
19/05/2011 @ 12:15 room GC C3 30

Seismic design and assessment of bridges: selected issues

Prof. Dr. Paolo Franchin, Sapienza, University of Rome

The vast majority of bridges are relatively simple structures. This is most true for girder bridges whose span range has increased significantly to cover nowadays a vast proportion of bridges being built. De-spite their simplicity however bridges still pose challenging problems due to their dimensions and plan-extended character. Construction phases often dominate the superstructure design. From the seismic analysis point of view their simplicity is not associated with an equally simple and regular dynamic response. This pa-per presents an overview of recent research on the seismic design and assessment/retrofit of bridges focusing on some of the aspects which are still not adequately covered in the codes such as: the level of protection to be used when designing a new bridge; the level of protection to be provided when upgrading an existing bridge and in particular whether this should be differentiated with respect to that adopted for design; the appropriate methods of modeling and analysis with emphasis on the scope of nonlinear static methods and to the problems related to the selection of the input for response history analysis; soil-foundation-structure interaction (piers abutments integral bridges) and non-uniform support input representing two controversial issues that may be mature for an inclu-sion in routine bridge analysis.
SHORT BIO Dr. Franchin is an Assistant Professor in Structural Design at the Department of Structural Engineering and Geotechnics of Sapienza University of Rome. He graduated with honors in Civil Engineering from Sapienza University of Rome in 1997 received a MSc in Structural Engineering from University of California Berkeley in 1999 and a doctoral degree from Sapienza in 2001. His research is in the fields of Earthquake Engineering and Structural Reliability where he has more than 50 publications including a textbook on topics such as the seismic design and assessment/retrofit of bridges critical facilities such as hospitals and infrastructural systems. He is a member of Commission 7 "Seismic design" and of Task Groups 7.5 "High-performance materials and structural systems" and 7.7 "Performance-based Seismic Design" of the International Federation of Structural Concrete (fib). He is also a member of Sub-Committee 3 "Structural Reliability and Optimization" of the International Association of Structural Safety and Reliability (IASSAR).
26/05/2011 @ 12:15 room GC C3 30

Analysis of large slopes in the European alps by inverse analysis

Prof. Tom Schanz

It is well known that environmental processes can trigger a landslide and control subsequent movements. But often there is uncertainty in the explanation of the exact failure mechanisms which is essential in landslide forecasting, quantitative hazard assessment and management (e.g. design of early warning systems). For this study in particular we are interested in two locations 1st reworked Callovo-Oxfordian black marls of the South French Alps, because this kind of material is highly prone to hydrological triggered landslides and 2nd a case study in the North Italian Appenin. The objective of the work is the analysis of mechanisms that initiate failure and control subsequent motion of landslides in small-scale experiments and by numerical modeling.
CV Promotion Dr. sc. techn. , ETH Zurich 5/1994 Habilitation and venia legendi for Geotechnics, Universität Stuttgart, 6/1998 Universitätsprofessor, BAUHAUS-Universität Weimar, 6/1999 Universitätsprofessor, Ruhr-Universität Bochum, 3/2009
09/06/2011 @ 12:15 room GC C30

The influence of extreme events on sediment transport, channel bed conditions, and the accuracy of bedload transport calculations

Assistant Prof. Elowyn YAGER, Department of Civil Engineering, Center for Ecohydraulics Research, University of Idaho, USA

The sediment supply to steep streams is highly episodic and is partially a function of the magnitude and timing of landslides and debris flows. In these channels, clusters and steps of large boulders move only during extreme flow events, and significantly alter the flow hydraulics and the transport of the more mobile gravel. Bedload flux predictions are often inaccurate in these streams because they do not account for the influence of the immobile boulders and the highly variable sediment supply. We measured bedload transport rates, grain-size, and the boulder-step characteristics (e.g. protrusion) in the Erlenbach torrent (10% slope), Switzerland, over a period of 6 years. This period encompassed two extreme events that reorganized boulder steps. Bedload fluxes increased and bed grain sizes fined after each extreme event because of greater hillslope sediment supply, reduced bed armoring and particle interlocking. The boulder step protrusion was a power function of the bedload flux; protrusion increased with lower sediment availability and with time elapsed since the last extreme event. We previously developed a bedload transport equation that accounts for the influence of boulder steps on the flow hydraulics. We now incorporate a function for protrusion, to estimate the sediment availability during any flow event. Sediment transport predictions were within an order of magnitude of the measured values if they used a time-dependent protrusion. Use of a constant protrusion caused the predicted bedload fluxes to systematically over- or under- estimate the measured values. This suggests that protrusion may be used as a proxy for the relative sediment availability and that bedload flux predictions may be improved using stochastic functions for bed roughness and sediment supply. Elowyn Yager obtained her PhD in Geology at the University of California, Berkeley in 2006. After a postdoc at Arizona State University, she joined the faculty of Civil Engineering at the University of Idaho, where she is currently assistant professor at the Center for Ecohydraulics Research. Her research focuses on understanding the mechanics of sediment transport, hillslope erosion, and channel morphology using field measurements, laboratory flumes and numerical models. She studies the interaction between flow turbulence and sediment motion, the influence of vegetation on bedload transport and flow hydraulics, and the coupling between hillslope sediment supply and channel conditions.
23/06/2011 @ 12:15 room GC C30

Within-event spatially distributed bedload: linking fluvial sediment transport to morphological change

Associate Prof. Colin RENNIE, Faculty of Engineering, University of Ottawa, Canada
22/09/2011 @ 12:15 room GC C330

What long term road transport future? Trends and policy options

Prof. Stef Proost, Center for Economic Studies, Catholic University of Leuven

This article examines long-term trends and broad policy options and challenges related to the road transport sector and its congestion and environmental impacts. A brief review of long-term projections of demand for road transport suggests that problems related to road network congestion and greenhouse gas emissions are likely to become more pressing in the future than they are now. Next we review from a macroscopic perspective three policy measures aimed at addressing these problems: stimulating shifts in transport modes to decrease congestion and greenhouse gas emissions boosting low carbon technology adoption to reduce greenhouse gas emissions from cars and regulating land use to reduce road transport volumes. We find that although these policies can produce tangible results they may also have unintended and costly consequences. Bio: Stef Proost is full professor at the Catholic University of Leuven. At the KULeuven he teaches transport environmental and energy economics at the Faculty of Economics and Business and at the Engineering Faculty. He is director of a group of 10 researchers at the Center for Economic Studies that deals with environment energy and transport topics. He is co-founder of the Energy Institute of the KULeuven and co-founder of the spin-off Transport Mobility Leuven (TML)). He is specialised in using mathematical models to address public policy questions: optimal pricing and investment in transport choice of policy instruments for environmental policy energy pricing questions. He is co-author of the models TRENEN TREMOVE MOLINO MARKAL and GEM-E3 that are used widely in the EU. He coordinated and participated in several European research consortia (TRENEN-II FUNDING GEM-E3 PRIMES MARKAL CAPRI AUTO-OIL 2 UNITE MC-ICAM REVENUE etc.). He has served as expert for EU Administrations for Transport Environment Energy and Economic and Financial affairs for ECMT-OECD UIC for the Federal and Regional governments of Belgium and for several other national governments as well as for private firms in the energy and transport sector. Policy issues he studied over the last years include the deepening of the Scheldt the Iron-Rhine the Oosterweel bridge in Antwerp the selection of TEN-T projects the introduction of road pricing and the climate policy in the transport sector.
29/09/2011 @ 12:15 room GC C330

Structural Engineering 2050: How Academia Can Shape the Future

Prof. Dan Kuchma, University of Illinois

Structural engineering practice is governed by the available tools for analysis and design. It currently relies on linear elastic analysis tools to determine the distribution of demands in structures and then building codes-of-practice in an effort to ensure that all parts of a structure have adequate strength. This approach does not enable engineers to adequately design for performance under service load levels or overloads it does not encourage the use of new materials and design concepts and it suffers from the many and varied shortcomings of codes-of-practice.
Within the digital era of Building Information Modeling structural engineering practice would be transformed by the creation of computational tools that could predict the full inelastic response of structural systems with defined levels of accuracy for all aspects of performance. Academia is best positioned to lead this transformation but this will require changes in how research is conducted how students are taught and how codes-of-practice are developed. This presentation will focus on the activities of the author the US research community and the American Concrete Institute to support the creation and use of transformative computational tools.
Short Bio: Dan Kuchma received his PhD from the University of Toronto working under the direction of Michael Collins on the behavior of cracked structural concrete. He joined the faculty at the University of Illinois in 1997 where he is currently an Associate Professor. He is the chair of committee 445 on Shear and Torsion of the American Concrete Institute a consultant to the US Concrete Bridge Specifications committee and is also active in the International Concrete Federation and the US Network for Earthquake Engineering Simulation. His research interests are in all things concrete advanced testing methods numerical modeling model validation networked databases and sustainability.
06/10/2011 @ 18:00 room Polydôme

Extreme Weather Conditions in a Changing Climate

Dr Ghassem Asrar, Director World Climate Research Programme, World Meteorological Org. Geneva

Conférence en anglais avec traduction simultanée en français:
The simple proverb of "weather is what we get and climate is what we expect" is used to describe the relationship between weather and climate. In the recent years it has become increasingly more difficult to explain in this context the extreme weather conditions such as snow-storms heat-waves super tornadoes floods and droughts that we have been experiencing frequently with great intensity and duration around the world. There is an ongoing scientific debate on the connection between the changing characteristics of the extreme events and the Earth's warming climate and what to expect in the future. We will share the current state of scientific knowledge about the weather extremes and climate conditions based observations of the recorded events during the past few decades and the projections of future conditions by climate models.
Le Dr Asrar est actuellement directeur du programme de recherche sur le climat global à l'Organisation météorologique mondiale (OMM) à Genève. Auparavant. Il a administré le service des ressources naturelles et systèmes agricoles auprès du département américain de l'agriculture. Il a également officié durant 20 ans comme cadre scientifique de haut niveau au quartier général de la NASA. Dans ce contexte il a conduit des programmes internationaux de mesure des paramètres géophysiques au moyen de satellites de dernière génération mettant en relation les interdépendances entre les continents les océans l'atmosphère et la biosphère. Le Dr Asrar a reçu de nombreuses distinctions de la Société américaine de météorologie de la NASA de l'Institut américain de l'aéronautique et de l'astronautique ainsi que la prestigieuse Goddard Medal en 1998. Le Dr Asrar a effectué ses études en ingénierie civile et physique environnementale à la Michigan State University.
13/10/2011 @ 12:15 room GC C330

Some impacts of thermal behaviour in geoenvironmental engineering

Dr Peter Cleall

This talk will discuss the impact of thermal behaviour on a number of geoenvironmental engineering problems ranging from the high temperatures found in geological high level nuclear waste disposal facilities to the low temperatures found in regions of permafrost. A wide range of coupled processes will be considered including convection shrinkage/swelling phase change the movement of moisture due to gradients of vapour pressure matrix suction and cryogenic suctions and also the development of ice lenses. The talk will focus mainly on the development of coupled thermo-hydro-chemical-mechanical (THCM) theoretical and numerical models and their application to geoenvironmental problems. Results from experimental studies looking at moisture movement under thermal gradients and the development of ice segregation will also be presented.
Bio: Dr Cleall graduated from Cardiff University in 1994 with a first class honours degree in Civil Engineering. He remained in Cardiff to read for a PhD which he completed in 1998. His PhD focused on modelling the thermal-hydraulic-mechanical behaviour of expansive clays. Following a period as a researcher at the Geoenvironmental Research Centre he was appointed as an academic member of staff in 2002 in the Cardiff School of Engineering. He has just completed a 12 month secondment to the international consultancy Jacobs where he worked in the sustainable solutions area of the business. He also currently serves on the Geotechnique Advisory Panel and will be on the Advisory Panel for the forthcoming Symposium in Print. Dr Cleall’s research activities initially focused on coupled flow and deformation behaviour in soils and have developed to encompass a number of areas in the subject of geoenvironmental and geotechnical engineering. He has been actively involved in a number of international research programmes (for example the Prototype Repository project and the Integrated Project NF-Pro both key European Commission funded research activities in the area of geological disposal of high level nuclear waste). He has expertise in numerical and analytical modelling saturated and unsaturated soil behaviour pollutant movement in the subsurface behaviour of freezing and thawing soils thermal ground energy and subsurface gas generation flow and management.
20/10/2011 @ 12:15 room GC C330

Uncertainties in Engineering Analyses - Concepts and Applications of Imprecise Probabilities

Prof. Michael Beer

Predicting the behavior and reliability of engineering structures and systems is often plagued by uncertainty and imprecision caused by sparse data, poor measurements and subjective information. Accounting for such limitations complicates the mathematical modeling required to obtain realistic results in engineering analyses. In the seminar options for the modeling of uncertainty and imprecision are reviewed from an engineering perspective. Imprecise probabilities are discussed as a general framework for the simultaneous consideration of stochastic and non-stochastic characteristics. This includes various points of view in the modeling associated with evidence theory, interval probabilities, p-box approach, and with fuzzy probabilities. Engineering examples demonstrate the applicability and usefulness of the concepts.
About the Speaker: Michael Beer is Professor of Uncertainty in Engineering in the Centre for Engineering Sustainability, School of Engineering, University of Liverpool. He graduated with a doctoral degree in Civil Engineering from the Technische Universität Dresden, Germany. As a Feodor-Lynen Fellow of the Alexander von Humboldt-Foundation Dr. Beer pursued research at Rice University together with Professor Pol D. Spanos. From 2007 to 2011 he worked as an Assistant Professor in the Department of Civil & Environmental Engineering, National University of Singapore. His research is focused on non-traditional uncertainty models in engineering with emphasis on reliability analysis and on robust design. Dr. Beer is a Member of ASME, Charter Member of the ASCE Engineering Mechanics Institute, Member of the European Association for Structural Dynamics, Member of IACM, as well as Member of the Editorial Board of Probabilistic Engineering Mechanics and Computers & Structures.
03/11/2011 @ 12:15 room GC C330

The Multi Actor Multi Criteria Analysis (MAMCA) methodology

Prof. Cathy Macharis

The multi-actor multi-criteria analysis (MAMCA) method to evaluate transport projects will be presented. This evaluation methodology specifically focuses on the inclusion of the different actors that are involved in the project the so called stakeholders. As the traditional multi criteria analysis it allows to include qualitative as well as quantitative criteria with their relative importance but within the MAMCA they represent the goals and objectives of the multiple stakeholders and by doing so allow to include the stakeholders into the decision process. The theoretical foundation of the MAMCA method will be shown together with several applications in the field of transport appraisal. Bio: Cathy Macharis is Professor at the Vrije Universiteit Brussel. She teaches courses in operations and logistics management as well as in transport and sustainable mobility. Her research group MOSI-Transport and logistics focuses on establishing linkages between advanced operations research methodologies and impact assessment. She has been involved in several national and European research projects dealing with topics such as the location of intermodal terminals assessment of policy measures in the field of logistics and sustainable mobility electric and hybrid vehicles etc. She is the chairwoman of Brussels Mobility Commission. Website: www.vub.ac.be/MOSI-T and www.mobi.vub.ac.be
10/11/2011 @ 12:15 room GC C330

Aging, Shaking and Cracking of Infrastructures: Dams and Nuclear Containment Vessels

Prof. Victor Saouma

When major concrete structures such as dams or nuclear reactors are aging (usually due to chemically induced volumetric expansion such as AAR) or are rattled by earthquakes most often major cracks occur and jeopardize their structural integrity. Structural assessment of critical and complex infrastructures is far more complex than the linear elastic analysis associated with their design. Full static or transient nonlinear analyses must be undertaken. Such an analysis must be rooted in solid theoretical models. This talk will draw exclusively from the speaker’s personal experiences and will address the finite element modeling of concrete dams and nuclear reactor containment vessels. The path from testing to model to implementation to assessment and finally to application will be highlighted. It will be shown that nonlinear analysis can be used to perform a structural safety assessment of critical infrastructures in lieu of simplistic (and possibly riskier or more expensive) alternate solutions. Short Bio: Victor Saouma is a Professor of Civil Engineering at the University of Colorado in Boulder. His research activity on dynamic analysis of dams has been funded for nine years by the Tokyo Electric Power Company (TEPCO) on AAR by the Swiss Federal Office of Geology and Water. Most recently he was a consultant to explain the root cause for the delamination of a nuclear containment vessel. Prof. Saouma is President elect of IFraMCoS and a member of the Nuclear Regulatory Commission panel on concrete structure deterioration.
17/11/2011 @ 12:15 room GC C330

Modelling and Solving Hazardous Materials Routing and Scheduling Problems

Prof. Konstantinos G. Zografos

The shipment of hazardous materials constitutes a serious transportation safety problem. Although hazardous materials accidents are rare, their consequences (e.g., fire, explosion, chemical spills) are severe and may endanger human lives and/or cause property damage and environmental pollution. Planning safe truck routes is considered an effective, pro-active risk mitigation measure. Thus, hazardous materials transportation and distribution decisions, in addition to conventional business objectives, should also consider risk minimization objectives. Hazardous materials routing problems can be grouped into two broad categories: i) single origin-single destination full truckload and ii) single origin-many destinations less than truckload. Although substantial research effort has been devoted to the former category, limited work has addressed the latter. In this talk, we present the evolution of hazardous materials routing and scheduling models and we propose a new formulation that takes into account the multi-objective nature of hazardous materials routing decisions and the dynamic characteristics of the underlying roadway network. The hazardous materials distribution problem is formulated as a bi-objective, time-dependent vehicle routing and scheduling model with time windows. A heuristic algorithm was developed to solve the proposed model. Computational results from the application of the proposed algorithm to problem instances of realistic size are also presented.
Bio: Konstantinos G. Zografos is Professor at the Department of Management Science and Technology of the Athens University of Economics and Business and Director of the Transportation Systems and Logistics Laboratory. His professional expertise, research and teaching interests include Applications of Operations Research and Information Systems in Transportation Systems and Logistics Management. He has published more than 100 papers in academic journals and conference proceedings. Professor Zografos has served as a consultant to governmental agencies, companies and international organizations, in USA, Europe and Greece and has been involved as a principal investigator in more than 60 R&D projects. He has received the ENO Foundation for Transportation award, the 2005 President's Medal Award of the British Operational Research Society, the Edelman Laureate Honorary Medal of INFORMS in 2008 for significant contributions to Operations Research, and other awards.
24/11/2011 @ 12:15 room GC C330

Performance-Based Engineering of Resilient Communities

Prof. Bozidar Stojadinovic

Communities are complex systems of people, structures and infrastructure, both physical and social. Response of communities to disasters is much more than the sum of the responses of its constitutive parts. Yet, today, design methods are focused on individual structures, as if they each were standing alone. For example, we have tools to predict the seismic response of individual highway bridges but we lack methods to predict the response of the entire regional highway system to a disaster. Resilience of communities is, therefore, difficult to engineer using the present framework. In this talk I will present a probabilistic performance-based framework for engineering resilient communities that addresses systems of structures and infrastructure rather than collections of individual entities. First, I will attempt to define the seismic resilience of communities, and describe the properties of a performance-based community-level seismic design framework. Second, I will illustrate the fundamental knowledge, enabling technologies, and engineered systems needed to constitute the new framework using three examples from my ongoing research: rocking of post-tensioned bridge columns; modeling bridge ability to carry traffic load after an earthquake; and evaluation of how new technologies and materials, such as base isolation and fiber-reinforced concrete, affect system design choices. Third, I will conclude by outlining the framework for performance-based engineering of resilient communities, focusing on the changes in hazard exposure and performance objective selection. I will also discuss the new research needed to implement such design framework in civil engineering practice. Society of tomorrow must have an order of magnitude more confidence in the resilience of the physical and social infrastructure then it does today. Performance-based engineering of resilient communities is an important contribution Civil Engineers can make towards this worthy goal. Bio: Dr Bozidar Stojadinovic recently joined the ETH Zurich as full professor of Earthquake Engineering and Structural Dynamics. His research interest comprise, for example, the development of probabilistic performance-based seismic design tools and the simulation of earthquake motion and response of structures in an urban region. Bozidar received numerous awards among these the ASCE Walter L. Huber Civil Engineering Research Prize in 2004.
08/12/2011 @ 12:15 room GC C330

Nouvelle approche du dimensionnement mécaniste-empirique des chaussées souples

Prof. Alan Carter

Le dimensionnement des chaussées a pour but de s’assurer qu’elles permettent aux usagers de se déplacer en sécurité avec un certain confort. Dans la plupart des régions du monde, le dimensionnement des chaussées est basé principalement sur l’expérience, et n’a que peu, ou pas, de fondement scientifique. Il s’agit de méthodes de dimensionnement empiriques. Les méthodes empiriques ont l’avantage d’être simple, mais s’adaptent difficilement aux nouveaux matériaux ou à l’accroissement des charges du trafic. Les nouvelles méthodes de dimensionnement mécaniste-empiriques utilisent des caractéristiques intrinsèques des matériaux et des lois d’endommagements couplées à des statistiques pour prédire l’état d’une chaussée dans le temps. La méthode de dimensionnement de chaussée mécaniste-empirique développé à l’École de technologie supérieure à Montréal est une méthode itérative relativement simple qui permet de prédire l’évolution de l’orniérage et de la fissuration par fatigue des chaussées flexibles dans le temps. L’utilisation de résultats d’essais de module complexe, de même que de résultats d’essais de caractérisation à la fatigue, mesuré par un essai cyclique en tension-compression uni axiale, sont utilisés dans cette méthode. Les résultats préliminaires ont montrés que cette méthode s’adapte bien aux nouveaux matériaux et au trafic, même si les fonctions de transferts permettant de faire le lien entre les conditions de laboratoires et l’état réel des chaussées doivent être optimisées.
Bio: Alan Carter est professeur au département de génie de la construction à l’École de technologie supérieure (ÉTS) à Montréal (Canada) depuis 2005. Les travaux de recherche du professeur Carter portent principalement sur le retraitement à froid des matériaux bitumineux, sur les traitements de surfaces, sur les enrobés tièdes et semi-tièdes ainsi que sur le dimensionnement des chaussées. Le professeur Carter fut le directeur de la division infrastructure de l’association québécoise des transports et des routes (2008-2010) et il est actuellement le directeur pour le Québec de l’association canadienne technique du bitume (CTAA).
01/03/2012 @ 12:15 room GC C330

Multi-level model predictive traffic control for sustainable mobility

Prof. Bart De Schutter

In this presentation we will give an overview of the work of done at the Delft Center for Systems and Control in the field of traffic management and control. We will in particular focus on how model-based predictive control (MPC) can be used to obtain a balanced trade-off between reduction of total time spent, emissions, and fuel consumption. To this aim we will discuss the macroscopic models we have been developing for fuel consumption, emissions, and dispersion of emissions as well as the details of MPC for traffic. We will also discuss efficient implementation through the use of parametrized control laws. Finally, we present a multi-level control traffic management strategy based on MPC with a focus on the area controllers in large-scale urban traffic networks, where we use the macrosopic fundamental diagram developed by Geroliminis and Daganzo in combination with mixed integer linear programming to obtain a tractable control approach.

Bio: Bart De Schutter is full professor at the Delft Center for Systems and Control of Delft University of Technology in Delft, The Netherlands. He received the PhD degree in Applied Sciences (summa cum laude with congratulations of the examination jury) in 1996 at K.U.Leuven, Belgium. Next, he was a postdoctoral researcher at the SISTA group of K.U.Leuven, until he moved to Delft University of Technology in 1998 as assistant professor. In 2000 he became associate professor and in 2006 full professor in the field of hybrid control and intelligent transportation systems. He is associate editor of Automatica and of the IEEE Transactions on Intelligent Transportation Systems. His current research interests include control of intelligent transportation and infrastructure networks, hybrid systems control, discrete-event systems, multi-agent systems, and optimization.

Organized by Civil Engineering Seminar Series (Co-organiseres: Prof. Nikolas Geroliminis, Prof. Katrin Beyer)
09/03/2012 @ 12:15 room GC B330

Recent Advancements of Concrete Walls for Seismic Applications

Prof. Sri Sritharan

With funding from the Network for Earthquake Engineering Simulation Research (NEESR) program of the National Science Foundation, seismic behavior of rectangular cast-in place concrete walls and an equivalent precast wall system has been studied. In addition, complex behavior of T-shaped concrete walls subjected to multi-directional loads has been investigated. The rectangular cast-in-place walls has focused on the influence that the anchorage of the wall longitudinal reinforcement into the footing has on the in-plane response concrete walls while the precast system was motivated to produce a low-damage self-centering wall option with superior seismic response to that observed for the cast-in-place walls. The T-walls were used to investigate their complex seismic behavior and the ability to predict their behavior under multi-directional loads. All of the investigations included large-scale tests and advanced analytical simulation based on fiber-based or equivalent finite element models.

The presentation will focus on the motivation for the study, lessons learned, advancements made to simulation capabilities, and recommendations for design and analysis. It will be concluded with some details of an ongoing NEESR research on precast concrete walls.

Bio: Dr. Sri Sritharan is the Wilson Professor of Engineering and Associate Chair of the Department of Civil, Construction and Environmental Engineering at Iowa State University. Sri’s research expertise includes earthquake-resistant design of structures, precast structural systems, soil-foundation-structure interaction and Ultrahigh Performance Concrete. Sri has engaged in NEES research since its inception and an active member of several professional societies. He is the current chair of the American Concrete Institute Committee on Earthquake-Resistant Concrete Bridges and serves on PCI’s Research and Development and Piling committees. Sri has won several awards including PCI’s Young Educator Achievement Award and Martin P. Korn award as well as the Best IT Innovation award from NEES.

Organized by Civil Engineering Seminar Series (Co-Organisers: Prof. Nikolas Geroliminis, Prof. Katrin Beyer)
14/03/2012 @ 12:15 room GC C330

Structures in Fire or Fires in Structures?

Prof. José L. Torero

The development of the concept of structural resistance to fire in the late 19th century enabled the transformation of infrastructure such as tall buildings or the use of steel as a construction material. Once century later the concept of fire resistance is still used in a generalized manner. During the last two decades, dramatic improvements in the understanding of structural behaviour in fire has enabled the design and construction of many buildings that do not meet the code compliant requirements of fire resistance. In the same period we have experienced the biggest structural failures due to fire within buildings that fully met the required fire resistance raising many questions associated to the validity of the fire resistance concept. It has become clear that fire resistance is not an absolute guarantee for structural stability in fire; nevertheless it is not clear where the weaknesses lie. Structural behaviour in fire has thus receive great attention but the definition of the “fire load” has been fundamentally neglected, ignoring how the modern build environment has displaced us away from the standard temperature vs. time curve. This presentation will discuss the weaknesses and strengths of the fire resistance concept emphasizing both the fundamental understanding of complex structural behaviour (tensile membrane action, spalling, material properties, etc.) and the nature of the “fire load” in modern built environments (definition of space, fuel loads, ventilation, etc.).

Bio: Jose L. Torero (FREng, FRSE, CEng, PhD) is BRE Trust/RAEng Professor of Fire Safety Engineering and Director of the BRE Centre for Fire Safety Engineering at the University of Edinburgh. Fellow of the Royal Academy of Engineering and Royal Society of Edinburgh and recipient of the 2008 Arthur B. Guise Medal from the Society of Fire Protection Engineers (USA) and the 2011 Rasbash Medal from the Institution of Fire Engineers (UK) for eminent achievements in the science, engineering and education in Fire Safety. Author of more than 150 journal publications and 500 technical documents in conferences around the world. Member of many technical and standards committees, editor of Fire Safety Journal as well as editorial boards of diverse journals in the fields of architecture, combustion, energy and fire.
Leading expert in the development of fire safety solutions for complex environments that include spacecraft, tunnels, oil platforms, historic building, nuclear power plants and tall buildings among others. His work crosses the boundaries of civil, chemical, mechanical and aerospace engineering as well as architecture, sustainability and preservation of the environment. Participated in landmark investigations of WTC 1, 2 & 7 collapses, Madrid Windsor Tower fire and Buncefield explosion and fire as well as in unique building designs like the Heron Tower (London) or the Space Shuttle Hangars in Florida.

Organized by Civil Engineering Seminar Series (Co-Organisers: Prof. Nikolas Geroliminis, Prof. Katrin Beyer)
20/03/2012 @ 18:00 room CM 1 3

11 septembre : de 2001 à 2011, dix ans, dix leçons pour une infrastructure durable

Prof. José Torero, Université d'Edinburgh, Chaire Landolt et Cie

L’effondrement des tours jumelles du World Trade Center met en exergue un insuccès de l’ingénierie structurale actuelle aux conséquences dramatiques. C’est dans un contexte nébuleux de spéculations, de controverses et de théories du complot qu’a été conduite l’une des plus exhaustives, mais aussi des plus coûteuses analyses de tous les temps pour comprendre cet insuccès. Par ailleurs, après l’événement du 11/9/2001, le monde a vécu une évolution extraordinaire au niveau de la construction de super tours, dont toutes, à une exception près, sont en Asie. En parallèle, la prise en compte de la durabilité dans la construction a conduit à la conception de super tours faisant appel à des niveaux d’innovation encore jamais atteints jusqu’ici. La conférence a pour objectif d’identifier, à travers une décennie de questionnements et d’innovations, dix leçons pour réaliser des infrastructures durables.
José Luis Torero est professeur à l’Université d’Edinbourg, où il dirige le Centre d’ingénierie en sécurité anti-feu, financé par le BRE Trust (Building Research Establishment) et la Royal Academy of Engineering (RAEng). Membre de cette dernière et de la Royal Society d’Edinbourg, José Torero est connu mondialement pour ses recherches de pointe en matière d’ingénierie de protection contre le feu et pour le développement de programmes d’enseignement innovants dans de nombreux pays.
Il a d’ailleurs reçu de nombreuses distinctions prestigieuses pour ses activités de recherche et d’enseignement. Le Prof. Torero est l’auteur
de plus de 500 publications, éditeur du Fire Safety Journal et membre
de plusieurs comités scientifiques.
Il est aussi consultant pour des organismes gouvernementaux et privés dans le monde entier. C’est
à ce titre qu’il a participé à l’expertise qui a suivi l’effondrement des Twin Towers.
22/03/2012 @ 12:15 room GC C330

Early-age deformations and cracking in high-performance concrete: measurements, modelling and mitigation

Prof. Pietro Lura

The matrix of a high-performance concrete typically has low porosity, typically obtained by keeping a low water-to-cement ratio and by silica fume addition. High-performance concrete possesses advantageous properties compared with traditional concrete, e.g. high strength from early ages, low permeability and improved durability. However, its practical application of faces some difficulties, in particular due to sensitivity to early-age cracking. These cracks constitute a serious problem with regard to strength and especially to durability. A main cause of early-age cracking is restrained autogenous deformation, a direct consequence of cement hydration in a low water-to-cement mixture. Another cause of cracking is represented by thermal stresses that are a consequence of the exothermic nature of cement hydration.
As cement hydration proceeds in low water-to-binder ratio concrete, the water becomes bound into hydration products and adsorbed on their surfaces. The capillary pores are emptied and the air-water menisci become progressively smaller, the internal relative humidity (RH) drops (self-desiccation) and an increasing capillary tension is produced in the pore fluid. The capillary stress exerts a compressive stress on the whole porous body, resulting in bulk shrinkage.
Self-desiccation occurring in low w/c cement paste leads not only to autogenous shrinkage, but also causes a substantial increase in the coefficient of thermal expansion in the cement paste. The latter effect is due to the RH changing with temperature which causes additional expansion acting in the same direction as the pure thermal dilation of a partially saturated medium.
Internal curing by means of superabsorbent polymers (SAP) is a method for promoting hydration of cement and limiting self-desiccation and further self-desiccation shrinkage. SAP are introduced dry into the mixture and form stable, water filled inclusions by absorbing pore solution. This water is released to the cement paste during hydration, as clearly shown by neutron tomography experiments. SAP are effective in both eliminating autogenous shrinkage and decreasing the thermal expansion coefficient of the cement paste, thereby reducing the risk of early-age cracking.
In this presentation, our work on early-age deformation in high-performance concrete will be presented, including experiments, poromechanical modelling and mitigation techniques.

Bio: Pietro Lura is Head of the Concrete and Construction Chemistry Laboratory since 2008 and professor at ETH Zurich, Institute of Building Materials, since 2011. He received his MS in 1998 from the University of Brescia, Italy, and his PhD in 2003 from the Delft University of Technology, The Netherlands. He has been assistant professor at the Technical University of Denmark (2003-6), visiting researcher at the National Institute for Standard and Technology (2002) and at Purdue University (2005), and patent examiner at the European Patent Office in Munich, Germany (2006-8).
His research interests include hydration and early-age properties of concrete, in particular microstructure development, shrinkage, setting, early-age cracking and internal curing. In these fields he has done important contributions to both understanding of the fundamental mechanisms and to advancement in the state of the art. His work on measuring techniques of autogenous deformation earned him two awards from the Transportation Research Board, the Bryant Mather Award in 2006 and the Fred Burggraf Award in 2007. For his work on internal curing he received the American Concrete Institute Wason Medal for Materials Research in 2007. He received for the second time the ACI Wason Medal in 2009 for his contribution to the understanding of the mechanisms of plastic shrinkage cracking. In 2009 he also received RILEM L'Hermite Medal in recognition of his outstanding contribution to the study of the early-age behavior and volume instability of cement-based materials.
In addition to heading the Concrete and Construction Chemistry Laboratory at Empa, Pietro Lura is teaching at ETH Zurich since 2009. He is also active in teaching and organizing summer courses targeted both at students and practitioners.

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
29/03/2012 @ 12:15 room GC A330

Monitoring Rock Properties with the Ambient Seismic Noise: Evidences for Non-linear Response of the Crust to Weak Deformations

Prof. Michel Campillo

We use the ambient noise to image the geological structures and to monitor slight changes in the elastic properties of the crust. This recently developed technique takes advantage of the huge quantity of data provided by continuous digital seismic networks. We discuss the principle of the method and show its applications for imaging at different scales. We present examples of temporal changes of seismic speeds associated with volcanic eruptions, earthquakes and transient deformation ('creep') at depth. We discuss the possible origins of these changes.

Bio: Dr. Michel Campillo is distinguished Professor (Professor ‘Classe Exceptionnelle’) at Université Joseph Fourier, Grenoble and senior fellow of ’Institut Universitaire de France’. He is head of research group “Ondes et Structures” of ISTerre (since 2004). His present research is related to the projects: Whisper - ERC Advanced grant : Towards continuous monitoring of the continuously changing Earth and G-GAP - ANR project : New perspectives on seismic hazard in subduction zones: Episodic Tremors and Slip, passive monitoring, tectonics and strong motion scenarios. He is member of the board of Université Joseph Fourier, of the Board of Directors of the Seismological Society of America and of the Comittee for Ethics of CNRS . He is the author of about 140 publications in international peer-reviewed journals (h=36 according to ISI).

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
19/04/2012 @ 12:15 room GC C330

Applications of Optimal Control Theory in Civil and Environmental Engineering

Prof. Ilya Ioslovich

On optimal irrigation scheduling

Optimal irrigation scheduling based on a dynamical model is analyzed, and global optimality has been proven with the use of sufficient conditions. The rather simple dynamic model has been used here. The model has two state variables: plant biomass and soil moisture. The optimal trajectory, i.e. the optimal irrigation scheduling, generally contains three periods: (i) maximal irrigation up to the optimal level of soil moisture, (ii) intermediate irrigation that maintains soil moisture at the optimal level which is a singular arc and (iii) no irrigation until the end of the growth season. This approach uses Krotov’s sufficient conditions of optimality, Krotov’s global bounds method, and Hamilton-Jacobi-Bellman formalism.

Time-Optimal Traffic Control Synthesis for a Signalized Isolated Intersection

The minimum time optimal control problem for a signalized intersection is defined as finding the green split that dissolves all initial non-zero queue lengths in minimum time. Here, the optimal minimum time control for an isolated intersection is found in explicit state feedback form, where the state is defined as the queue lengths, by the use of a clever modification of D. Gazis’s continuous differential model, and the Pontryagin Maximum Principle. The closed form feedback solution is presented for all types of constraints on the maximal green split values, and on the queue lengths, i.e. with constrained control and state variables. In general, the minimum time optimal solutions are non-unique. It is also demonstrated that the known contribution by D. Gazis (1964) alleged to solve the minimal “total delay” problem is in fact a minimal time solution in a particular region of the state space.

Bio: Prof. Ilya Ioslovich was born in Moscow, Russia, in 1937. He received the M.Sc. degree in mechanics from Moscow State University, Moscow, in 1960, and the Ph.D. degree in physics and mathematics from Moscow Institute of Physics and Technology (Phys-Tech), Moscow, in 1967. He held positions of head of lab and head of division in different research Institutions in Moscow. Since 1991, he has been with the Faculty of Agricultural Engineering, Technion, Haifa, Israel. Since 2002, he was Full Professor in the Faculty of Civil and Environmental Engineering, Technion. Since 2012 he is scientific consultant at Technion Research and Development Foundation Ltd. His current research interests include optimization of agricultural, environmental and transportation systems, space research, optimal control, identification, and modeling. Prof. Ioslovich is recipient of two silver medals for industrial achievements from the Soviet All-Union Exhibition in 1976 and 1983.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
26/04/2012 @ 12:15 room GC C330

Travel Behavior Models and Applications to Time-of-Travel, Value of Time, and Mode Switching Decisions

Prof. Maya Abou-Zeid

Travel behavior models predict individual decisions related to various travel dimensions, such as the choice of auto ownership, activity patterns, destinations visited, modes of transportation, routes, and departure times. They are used as part of decision support systems by transportation planners and policy makers to predict travelers' responses and traffic impacts resulting from infrastructure (e.g. road widening), operational (e.g. public transportation service improvement), or policy interventions (e.g. congestion pricing). The accuracy of these decision support tools depends on the richness embedded in the travel behavior models.

This talk will give an overview of some recent developments in the area of travel behavior modeling with applications to modeling time-of-travel choice accounting for the cyclicality of time-of-travel, modeling heterogeneity across individuals in the value of travel time savings arising from different attitudes towards travel modes, and modeling mode switching from car to public transportation in relation to travel happiness using recent experiments conducted with habitual car drivers in Switzerland and in Boston. The applications show how insights from behavioral theories can be used to enrich the travel demand models and make them more policy-sensitive.

Bio: Maya Abou-Zeid is an Assistant Professor of Civil and Environmental Engineering at the American University of Beirut and a research affiliate of the Intelligent Transportation Systems Program at the Massachusetts Institute of Technology. Her research interests include travel behavior modeling, urban transportation planning, market research, and road safety.

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
10/05/2012 @ 12:15 room GC C330

Key Research Themes for Cellular FRP (Fibre Reinforced Polymer) Bridge Decks

Dr. Wendel Sebastian

Carbon and glass FRP (fibre reinforced polymer) materials possess four beneficial properties, namely high stiffness-to-weight ratios, superior strength-to-weight ratios, corrosion-resistance and ease of manufacture into construction-friendly shapes. Consequently, these FRPs are finding increased applications in strengthening existing structures and in construction of new road bridges. For the latter application, cellular bridge decks made of glass FRPs are only 20% the weights of reinforced concrete bridge decks. This low weight, coupled to the modularity and durability mean that GFRP cellular decks can potentially lead to a new class of deck-on-beam road bridges which are much more rapidly constructed (so reducing disruption to traffic flow during assembly) and are of significantly longer service lives than are currently possible. Despite this strong potential, cellular FRP deck bridges are not widespread. The presentation by Dr Sebastian will examine some of the key reasons – including observations from the few FRP deck bridges in service – for the slow uptake of this new technology. This will naturally lead on to the nature of the underpinning research needed to develop robust design guidance which will overcome these limitations. In so doing, the presentation will focus on specific research topics including the structural integrity of the deck-to-beam connections, along with combined environmental and fatigue long-term effects on these novel bridge decks. The talk will conclude with a road map for development of FRP bridges over the next 10 years.

Short Bio: Dr Wendel Sebastian is senior lecturer in Structural Engineering at Bristol University in the UK. He gained his BA in Engineering and his PhD in Structural Engineering from the University of Cambridge. His research entails the uses of nonlinear algebraic analyses, nonlinear computational approaches and large-scale tests to elucidate and optimise the load responses of composite structures comprising various combinations of traditional (steel, concrete, timber) and new (FRP (fibre reinforced polymer), limecrete) materials. This research now focuses on road bridges made wholly or partly of FRPs. He now leads a project, funded by partners including the UK Highways Agency, to study the fatigue behaviour of an 8 m long, 4 m wide FRP deck bridge specimen within a test frame developed ad hoc at the University of Bristol. Dr Sebastian is currently the recipient of a Leverhulme Trust Senior Research Fellowship from the Royal Academy of Engineering.

Organized by EDCE (Prof. Nikolas Geroliminis & Prof. Katrin Beyer)
31/05/2012 @ 12:15 room GC C330

Design of Concrete Structures under Seismic Actions – Flat Slabs and the EC8

Prof. António Pinho Ramos

The devastating social and economic impacts of recent earthquakes in urban areas have resulted in an increased awareness of the potential seismic hazard and the corresponding vulnerability of the built environment.

Flat slab structures are a widespread solution all over the world. They possess many advantages in terms of architectural flexibility, use of space, easier formwork and shorter construction time. However the lack of knowledge about their behavior under seismic action and the insufficient lateral resistance presents limits to their application in areas of medium to height seismic risk.

For that reasons, section 5 of EN 1998-1:2004 states that its provisions do not fully cover concrete buildings with flat slab frames used as primary seismic elements. Nevertheless flat slabs structures have performed well in recent earthquakes, and should not be discarded as a solution used in that areas. Research efforts should be directed towards extending the scope of EN 1998-1 to cover flat slab structures as primary seismic elements, to the benefit of both economy and seismic safety.

Bio: Prof. António Pinho Ramos has been a faculty member at Universidade Nova de Lisboa since 1999. He obtained his licentiate, M.S and Ph.D. from Technical University of Lisbon, in 1990, 1995 and 2003, respectively. Prof. António Pinho Ramos primary research interests include the behavior of concrete and presstressed concrete structures, mainly punching and shear behavior. He is a member of UNIC – Research Center in Structures and Construction of Universidade Nova de Lisboa. He is also the Director of the Universidade Nova de Lisboa Structural Engineering Laboratory. At the professional level Prof. António Pinho Ramos works as a design and consultant engineer.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
10/10/2012 @ 12:15 room GC B330

Geotechnical Aspects of the Canterbury Earthquake Series

Dr. Liam Wotherspoon

The city of Christchurch and the surrounding towns in the Canterbury region of New Zealand suffered significant damage during the 2010-2011 Canterbury earthquake series. The most damaging was the Mw 6.2 earthquake on the 22 February 2011, resulting in 185 fatalities and severe damage to buildings and infrastructure. A major factor in this damage, and the damage in other earthquakes in the series was the severity and spacial extent of liquefaction. This presentation will provide an overview of the liquefaction-induced damage to the region during the Canterbury earthquake series and the progression of damage as a result of repeated liquefaction in many areas.

Bio: Liam Wotherspoon is the Earthquake Commission Research Fellow at the University of Auckland, New Zealand. He completed his PhD jointly at the University of Auckland and Iowa State University on a Fulbright Award. His research involves a range of earthquake engineering aspects, including soil-foundation-structure interaction modelling and field testing, resilience of ports, and geotechnical site characterisation. He was heavily involved in post-earthquake reconnaissance investigations and assessments during the 2010-2011 Canterbury earthquake sequence.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
10/10/2012 @ 18:00 room Auditoire CM 3

Conference Chaire Landolt & Cie – Future Africa

M. Jonathan Ledgard, Fellow, future Africa, EPFL, Africa correspondent, The Economist

Jonathan Ledgard is a leading contemporary thinker on risk and technology in emerging markets. He is a fellow at EPFL and a political and war correspondent for The Economist, based in Africa. He has written cover stories and leaders from over fifty countries. He is also a novelist.

Africa's population is doubling, its cities quadrupling. Africans are better educated and more vital than ever before. African minerals, timber, grains and meat are fetching record prices. At the same time, Africa is seeing the extermination of species, and is not producing enough food or jobs to guarantee stability. What is the future for the continent and what are the opportunities for science, technology and architecture?

Organized by Chaire Landolt & Cie
18/10/2012 @ 12:15 room GC C330

Modeling Drivers Behavior during Safety-Critical Events with Intelligent Agents

Prof. Dr. Montasir Abbas

Abstract: This presentation describes a novel methodology to model both safety and operational aspects of driver behavior in traffic (funded by the FHWA Exploratory and Advanced Research Program) using agent-based modeling and simulation techniques. Neuro-fuzzy reinforcement learning agents were developed and trained to clone the behavior of individual drivers during normal and safety-critical driving events. A naturalistic driving database was used for the training and validation of the developed agents. Robust agent activation techniques were also developed using discriminant analysis. The developed agents were implemented in VISSIM (a microscopic traffic simulation commercial software) and were evaluated by comparing the behavior of vehicles with and without agent activation. The results showed very close resemblance of the behavior of agents to driver data.
Bio: Dr. Montasir Abbas is an Associate Professor in the Transportation Infrastructure and Systems Engineering at Virginia Tech. He holds a Bachelor of Science in Civil Engineering from University of Khartoum, Sudan (1993), a Master of Science in Civil Engineering from University of Nebraska-Lincoln (1997), and a Doctor of Philosophy in Civil Engineering from Purdue University (2001).
Dr. Abbas areas of interests include traffic control, intelligent transportation systems, and traffic flow theory. He developed several algorithms and systems, including Purdue Real-time Offset Transitioning Algorithm for Coordinating Traffic Signals (Pro-Tracts), Platoon Identification and Accommodation system (PIA), Pattern Identification Logic for Offset Tuning (PILOT 05), Supervisory Control Intelligent Adaptive Module (SCIAM), and the Cabinet-in-the-loop (CabITL) simulation platform. He has conducted sponsored research of more than $2,000,000 as a principal or co-principal investigator. His research sponsors include the Federal Highway Administration, National Cooperative Highway Research Program, Virginia Center for Transportation Innovation and Research, and Texas Department of Transportation.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
01/11/2012 @ 12:15 room GC C330

An activity-based approach to analyzing walking

Prof. Dick Ettema

Studies of walking behavior have gained momentum over the past years, due to improved data collection techniques and further development of modeling approaches. In most cases, such studies emphasize the detailed movement of pedestrians in relation to aggregate pedestrian flows, and decisions regarding route or destinations during a walking trip. This presentation aims to look upon walking behavior from a broader perspective, by discussing the options of applying an activity based approach to walking behavior. In particular, it will be discussed to what extent decisions made regarding the daily (or longer term) activity pattern influence decisions regarding the walking trip (such as where to walk, for how long, with whom), decisions during the walking trip (such as routes, places to visit and activities to pursue while walking) and the experience of the walking trip (how pleasant, stressful etc.). It will be argued that looking upon walking from this broader perspective gives rise to the inclusion of addition variables in our analyses, including functional characteristics of places and routes (amenities, functions) as well as ambient conditions and aesthetics.

Bio: Dick Ettema is associate professor in the Department of Human Geography and Planning in Utrecht University. He received a PhD from Eindhoven University of Technology with a thesis “Activity-based Modeling” and edited the book “Activity-based Approaches to Travel Analysis” with Harry Timmermans. Since then, he has published widely on activity based analysis, activity based modeling and time-use studies. Dick’s recent work has focuses on the use of active travel modes and the impact of travel and activities on well-being.

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
08/11/2012 @ 12:15 room GC C330

Fatigue strength improvement of high strength steel welded joints treated by high frequency mechanical impact

Prof. Gary Marquis

Abstract: In the past decade, high frequency mechanical impact (HFMI) has significantly developed as a reliable, effective and user-friendly method for post-weld fatigue strength improvement technique for welded structures. The development of an IIW best practice guideline for implementing HFMI has
been hindered by the lack of directly comparable experimental data for numerous HFMI methods. In this study, nominally identical longitudinal non-load carrying attachments in high strength steel, fy = 690 MPa, were manufactured at a single location and randomly distributed to four HFMI equipment
manufacturers for treatment. Specimens were subsequently returned and fatigue tested on a single machine using identical variable amplitude loading histories. Detailed specimen alignment, weld profile and HFMI groove measurements were done for each specimen and X-ray diffraction based residual
stress measurements were performed on 10 specimens. While clear differences were observed, the HFMI groove dimensions and the resulting residual stress state following treatment were generally similar. Experimental results indicate that all of the HFMI improved welds from the four different HFMI
equipment manufacturers satisfied the previously proposed characteristic S-N line based on both the material yield strength and the specimen geometry. Results of the study are valuable and promising with respect to the development of a future guideline. The goal of the study has not been to compare
treatments, so specific data points are not associated specific HFMI equipment manufacturers.

Short Bio :
Gary Marquis is Professor of Mechanics of Materials, Aalto University School of Engineering. He received his degrees in mechanical engineering from University of Illinois at Urbana-Champaign (BSc, MCs), and Helsinki University of Technology (PhD). He is a worldwide known specialist in the field of fatigue of steel components and structures. He has published numerous papers and a reference book on multi-axial fatigue with Prof. Darrell Socie (http://books.sae.org/book-r-234). He is the president of Commission XIII of the International Institute of Welding (IIW) "fatigue of welded components and structures", which is the most active commission in the organization with 50 active members from 20 countries.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
15/11/2012 @ 12:15 room GC C330

Infrastructure Efficiency through Monitoring and Algorithmic Design

Prof. Eleni Chatzi

In recent years radical urban development is expressed through the construction of more impressive and significantly larger civil structures while at the same time a large part of existing infrastructure is reaching the end of its lifecycle. Meanwhile humanity is now realizing the urgent need for efficient resource management and the significance of sustainable systems. Providing a solution to this challenging problem is a twofold task for the engineer, involving on one hand efficient designs for new structures, and on the other hand the planning of appropriate maintenance and repair schemes for existing ones. Monitoring of infrastructure systems, also referred to as Structural Health Monitoring, can be a valuable source of information for evaluating structural integrity, durability and reliability throughout the structure life cycle as well as ensuring optimal maintenance planning and safe operation. The more recent developments in sensor technology and communication networks have allowed for the rapid deployment of dense sensor arrays at a relatively low cost. As a result, advanced computational methods are required in order to process and interpret the large bulk of obtained information. The proper combination of hardware resources and theoretical tools can ultimately lead to a “smart infrastructure management system”, where structural assessment no longer depends merely on sporadic visual inspections. Moreover, rigorous computational tools, including Finite Element simulation coupled with Computer Aided Design (CAD), may be used in order to produce structural forms that are both efficient in terms of structural response and innovative in terms of aesthetics and design. This presentation will address the benefits of monitoring and algorithmic design in infrastructure systems and provide examples of relevant implementations.

Bio: Eleni Chatzi is currently an assistant professor at the Chair of Structural Mechanics at the Institute of Structural Engineering, ETH Zurich. She has obtained her diploma (2004) and MSc (2006) in Civil Engineering, with honors, from the Department of Civil Engineering at the National Technical University of Athens (NTUA). She then obtained her PhD Degree with distinction from the Department of Civil Engineering & Engineering Mechanics at Columbia University in 2010. Her research interests include the fields of structural health monitoring, damage detection and nonlinear dynamics.

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
22/11/2012 @ 12:15 room GC C330

Portfolio risk assessment for the urban built environment to flooding

Prof. Fatemeh Jalayer

The urban built structures and lifelines in cities are particularly vulnerable to extreme climate-related events such as flooding. This seminar provides an overview of the activities of our research unit related to the identification of the urban hot spots and the assessment of vulnerability of the built environment to flooding in the context of the FP7 project Climate Change and Urban Vulnerability (CLUVA). A quantified risk-based methodology is presented in order to perform micro-scale evaluation of building vulnerability to flooding. This methodology is developed specifically for vulnerability assessment based on in-complete knowledge and relies on various data-gathering techniques such as Orthophoto boundary recognition, sample field survey and laboratory tests. A new GIS-compatible computer platform and Matlab-based user interface entitled "Visual Vulnerability & Risk" (Flooding module) --stemming from the above-mentioned methodology-- is illustrated. This integrated platform puts together vulnerability and risk assessment modules for flooding in order to generate detailed (micro-scale) risk maps for building stock with more-or-less similar characteristics. The GIS compatibility allows for graphical processing of both input and output to the program, facilitating an efficient visualization of flooding risk. These maps can be potentially used as supplementary technical support for flood risk mitigation, emergency preparedness, response and recovery.

Bio: Fatemeh Jalayer is Assistant Professor of Structural Engineering at the University of Naples Federico II. She has received her degrees from Stanford University (MS and Ph.D.) and Sharif University of Technology (BS and MS). She is a recipient of the 2003 Norman Medal of the Society of the American Engineers (ASCE). Her fields of research include structural vulnerability and risk assessment and the application of probabilistic methods in civil engineering problems. She is involved in pre-normative research efforts for the seismic reliability of existing buildings within the Italian RELUIS-DPC program. She is the lead researcher in the vulnerability and adaptation of buildings in the African urban setting to climate change in the context of the European project CLUVA.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
29/11/2012 @ 12:15 room GC C330

Propagation of Frictional Discontinuities

Prof. Antonio Bobet

The most important mechanism for deformation and failure in rock masses under relatively low stresses is slip along pre-existing discontinuities. As stresses increase relative to the strength of the rock (e.g. in very deep tunnels, open mine excavations, faults, etc.), failure through discontinuities as well as through the rock matrix becomes possible. The failure involves a complex mechanism of interaction between existing discontinuities, creation of new discontinuities, and coalescence.
In rocks, there is the tendency of cracks to initiate and propagate in tension due to the lower toughness of the material in tension than in shear. This initiation mechanism however may not be favored when predominant stresses are compressive. In compression, two types of cracks can be generated from a pre-existing discontinuity (flaw): wing or primary cracks and secondary cracks. Wing cracks are tensile cracks that initiate at or near the tips of a flaw and propagate in a stable manner towards the direction of maximum compression. Secondary cracks initiate from the tips of the flaws, propagate in a stable manner, and have been recognized as shear cracks. There are two possible directions for shear crack initiation: coplanar and oblique to the flaw. Crack coalescence through wing (tensile) cracks is just one possible mode of crack linkage, which occurs only with small confining stresses and for a particular flaw distribution. Coalescence through shear cracks is observed under a variety of flaw distributions, and is the only possible mechanism for crack linkage under moderate to large confinement. Propagation along a shear crack requires not only the creation of new surfaces, similar to what happens with tensile cracks, but also slip along the new surfaces. The mechanism for slip initiation is controlled by the strength drop required for the transition from peak to residual along the newly formed shear crack and on the displacement necessary for such transition. Laboratory experiments show that the mode II critical stress intensity factor is not a material property, as it strongly depends on confinement.

Bio: Dr. Bobet is a Professor of Civil Engineering at Purdue University, USA. He holds a bachelor degree in Civil Engineering from Technical University of Madrid in Spain and a Doctor of Science degree from Massachusetts Institute of Technology, USA. Dr. Bobet’s areas of interest include rock mechanics, underground structures, soil-structure interaction during seismic events and problem soils. He has extensive experience in practice. He was senior geotechnical engineer at Euroestudios, consulting engineers, in Spain for four years, and a construction manager for Ferrovial, Spain, also for four years.
He has authored or co-authored more than one hundred technical publications. He serves or has served on the Editorial Board of ASCE Journal of Geotechnical and Geoenvironmental Engineering, ASTM Geotechnical Testing Journal, Rock Mechanics and Rock Engineering Journal, and Tunnelling and Underground Space Technology Journal. He is a member and past chair of the ASCE rock mechanics committee, a Director of the Board of Directors of the American Rock Mechanics Association (ARMA), the co-chair of the Working Group on Suggested Methods for Failure of Intact Rock, appointed by the International Society of Rock Mechanics, and the Chair of the 2012 U.S. Rock Mechanics/Geomechanics Symposium. He is currently the Vice-president of the American Rock Mechanics Association. Dr. Bobet has received a number of awards, including the 2011 Ralph B. Peck Award from ASCE, the 2012 National Award for Significant Contributions in Science and Technology - SENACYT Panama, and the 2012 ARMA Research Award.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
13/12/2012 @ 12:15 room GC C330

The eXtended finite Element Method for 3D non-planar frictional cracks - Theoretical aspects and application to fretting fatigue

Prof. Anthony Gravouil

Three-dimensional crack growth simulations require both an accurate geometrical modeling of the crack and front shapes and a precise quantification of interface displacement and traction fields. Tribological fatigue like rolling fatigue, fretting fatigue involve three-dimensional crack problems in which the interfacial crack behavior is mainly governed by complex sequences of contact/friction states. In this context, enriched finite element methods (coupled for instance with a level set modeling of the possible non-planar crack shape) are very well suited to model discontinuous physical behaviors independently of a given initial mesh. These enrichments avoid the mesh compatibility of the crack with the bulk, the remeshing and the field interpolation when dealing with crack propagation modeling. However, many cases require to impose constraints on the enriched interfaces: Dirichlet boundary conditions, contact or frictional interfaces, etc... Unfortunately, imposing these constraints involves two drawbacks: On the one hand, it imposes to discretize the crack interface to address displacement and traction fields using interface elements based on bulk finite elements cut by the crack. Hence it involves a mesh dependency between the interface and the bulk. This work presents the key procedures to undertake the crack face contact problem when using X-FEM under a global-local approach. The use of the locally two-scale approach in a three field weak formulation ensures that sufficiently refined crack faces can be incorporated into the numerical models, avoiding an unaffordable refinement of the bulk mesh at the component level and thus keeping the spirit of the X-FEM. The need of the stabilization for the solution in the contact tractions is evidenced, especially for contact problems where sliding is important. For that purpose, a dedicated non-linear solver is introduced. A thorough numerical verification of the pro- posed methodology is presented. The combination of the three-scale X-FEM model and the non-linear solver enables the accurate resolution of the crack face frictional contact with a low computational cost and good stability properties. The application of the procedure to a 3D fretting fatigue test is then presented. The correlation with experimental testing is performed, taking into consideration the actual crack resulting from the tests by means of automated 3D crack geometry reconstruction. The contact state evolution is presented and gives an idea of the potential of the methodology developed, which is capable of analyzing several cracks simultaneously with high accuracy while keeping a reasonable computational cost thanks to the multi-scale approach. Such an approach can also be applied to a wide range of engineering applications implying complex frictional effects on 3D crack propagation.

Bio: Anthony Gravouil is Professor of Computational Mechanics and Structural Engineering at INSA de LYON, France. He has received his degrees from Ecole Normale Supérieure de Cachan, France (MS and Ph.D.). During his post-doc at Northwestern University (Chicago, USA), he developed the Extended Finite Element Method coupled with level sets for 3D crack propagation in collaboration with professor Ted Belytschko and Nicolas Moës. For 10 years, his fields of research at LamCoS laboratory (INSA de LYON, France) include the development of numerical methods efficient and robust (X-FEM) for the simulation of two-dimensional and three-dimensional crack propagation without remeshing (dynamic crack growth, fatigue crack growth with confined plasticity, tribological fatigue with contact and friction) in the team of professor Alain Combescure. These developments are made according to experimental validation (X-ray micro-tomography, 2D and 3D digital image correlation) for the identification of 3D crack growth laws. A second field of research concerns the development of space-time multi-scale methods for two-dimensional and three-dimensional transient nonlinear dynamics. The applications concern the simulation of crash and impact phenomena when multi-time scales effects occur. More recently, he developed reduced order modeling techniques related to these two areas: computationally efficient 3D fatigue crack propagation numerical models, space-time reduced order models for transient dynamics and engineering applications with frictional contact.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
17/12/2012 @ 12:15 room GC D0 386

Open-channel separating-flows

Prof. Emmanuel Mignot

In the field or in laboratory conditions, as a flow reaches a geometrical singularity, it usually detaches from the wall. A recirculation zone (also named “bubble”) takes place along this wall. The typical velocity magnitude in the recirculation zone is at least an order of magnitude lower than that of the main flow. Meanwhile, the main flow accelerates as the flow section is reduced. Consequently, a mixing layer takes place between the rapid main flow and the slow recirculating flow and this mixing layer strongly rotates from the detachment point towards downstream. Analysis of such separating mixing layer thus requires the use of a local frame-axis.
We investigate a separating flow on an experimental set-up of open-channel bifurcation with one incoming and two outing flows. Time-averaged PIV data permit to characterize this mixing-layer in terms of mean and turbulent flow characteristics. Moreover, a comparison between the analysis using Cartesian and local frame-axis confirms that the second methodology is much more convenient. We show for instance that the failure of eddy-viscosity concept in Cartesian frame-axis can be explained based on geometrical aspects and can be corrected using a local frame-axis.

Bio: Emmanuel Mignot is assistant professor at INSA (Lyon, France) for his academic work and LMFA (Laboratory for Fluid Mechanics and Acoustics, Lyon, France) for his research activities. His research is mainly based on an experimental approach and is dedicated to urban flooding and environmental fluid mechanics. Specific attention is paid towards complex mixing-layer configurations such as lateral cavities, junction and bifurcation flows, sudden flow enlargements, and flows around obstacles.

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
28/02/2013 @ 12:15 room GC C330

Introduction to FEM/DEM technology and its application to model of Excavation Damaged Zone (EDZ) in anisotropic rock formation

Prof. Giovanni Grasselli

The combined finite/discrete element method (FEM/DEM) is a numerical technology that combines DEM algorithms, which capture the interaction and fracturing of different solids, with FEM principles that describe the elastic deformation of discrete bodies. Damage and failure of rock material is simulated in FEM/DEM by explicitly modelling crack initiation and propagation using principles of non-linear elastic fracture mechanics.

The purpose of this presentation is three-fold:
(i) to present the basic concepts of the hybrid finite-discrete element method (FEM/DEM);
(ii) to illustrate the new approaches that have been introduced into the FEM/DEM technology to model layered materials; and
(iii) to demonstrate the effectiveness of this new modelling approach in simulating the development of fractures around a tunnel excavated in layered rock formation.

In this context, the term excavation damaged zone (EDZ) refers to the volume of rock close to an underground opening that has experienced irreversible deformation due to the excavation and where new fractures have occurred. With respect to the original host rock, EDZ is characterized by a reduced mechanical strength and a significant increase in its flow and transport properties. Thus, for both rock support design and permeability studies it is important to estimate the extent and the geometry of the EDZ, which is also influenced by the type of material and its internal microstructure. In particular, it has been observed that the EDZ in layered rock formations is heavily affected by the anisotropic mechanical response of the material due to the presence of bedding planes and it cannot be properly modeled using a continuum approach.

This presentation will also present how a transversely isotropic elastic constitutive law was implemented into FEM/DEM to account for the anisotropy in global elastic modulus, while procedures to incorporate a distribution of preferentially oriented defects and the presence of bedding planes were devised to capture the anisotropic strength of metamorphic and sedimentary rocks.

Finally, an example of model calibration and simulated fracture patterns around circular excavations will be then discussed in the context of the theory of brittle rock failure and analyzed with reference to the EDZ formation mechanisms observed at the Mont Terri Underground Research Laboratory, Switzerland.

Bio sketch:
Dr. Giovanni Grasselli is a full faculty member at the University of Toronto, Canada. He holds an undergraduate degree in Civil Engineering (1995) from the University of Parma, Italy, and a PhD in Rock Mechanics (2001) from the Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland. His doctoral thesis ‘‘Shear Strength of Rock Joints based on Quantified Surface Description’’ was awarded with the 2004 ISRM Rocha Medal. Previously to join University of Toronto, he has been research fellow at the Imperial College London (UK), and at the Sandia National Laboratories (USA). He has served as associate director of the Geomechanis Research Centre at Mirarco (Canada) in 2005 and of the Lassonde Institute for Mining at the University of Toronto in 2007-2009.

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
07/03/2013 @ 12:15 room GC C330

Cooperative ITS: technologies and societal impacts

Prof. Arnaud de La Fortelle

Intelligent transportation systems (ITS) are being deployed in many countries to solve many problems arising in transport such as safety, efficiency, pollution or economic costs. A number of technological advances make these systems viable such as increasing computer power or decreasing sensors costs. Communication and information sharing rose quickly in the last decades and we now see the possibility to couple all these systems, giving birth to cooperative systems. This talk will explain some features of these cooperative intelligent transportation systems. They are good candidates for our future but will be accepted only if their social impact is positive and if it is seen as positive (not Big Brother like). After all, their goals are social, not purely technical, so we have to consider various aspects.

Short Bio: Arnaud de La Fortelle got a PhD degree from Ecole des Ponts et Chaussées prepared at INRIA on theoretical properties of probability distributions (large deviations). He becomes director of the joint research unit LaRA (the automated road) between INRIA and Mines ParisTech in 2006. He moves to Mines ParisTech in 2006 where he becomes director of the Robotics Lab (CAOR) in 2008. During that period, he investigates communications for cooperative systems and the architecture needed in distributed systems. While keeping some fundamental research in probability theory, his main topic of interest is now cooperative systems (data distribution, control, mathematical certification) and their applications (e.g. Cybercars, collective taxis). He served the Board of Directors of IEEE Intelligent Transportation Systems Society 2010-2012 and is currently vice-president of the French ANR Sustainable Transports and Mobility evaluation committee. He is also ParisTech's coordinator of the Peugeot PSA – ParisTech collaboration.

Organized by Prof. Nikolas Geroliminis and Prof. Katrin Beyer
14/03/2013 @ 12:15 room GC C330

Reliability of motorway operation

Prof. Werner Brilon

Traditionally, traffic on highways is planned and operated with respect to the objectives safety, efficiency, ecology, and cost effectiveness. Meanwhile, however, the target of reliability is turning out as a dominating aspect of traffic performance.
Reliability is the probability that a highway facility can be used with a sufficient performance which reasonably can be expected as a minimum by road users. Times of congestion with significantly lower speeds constitute a breakdown of traffic flow. Breakdowns due to excessive traffic demand can be analysed using theoretical approaches obtained from lifetime statistics. The probability of traffic volumes which cause a breakdown can be described by a Weibull-distribution.
In addition to temporary overload, delays to traffic are also caused by work-zones and accidents/incidents. These occasional events are the source of major economic losses.
To investigate the consequences of unreliability of traffic operation on motorways it seems to be necessary to study the occurrence of congestion over longer periods, e.g. for a whole year (whole year analysis, WYA). This method makes it possible to analyse the combined effects from traffic engineering therapy and organisational treatments. WYA can also include effects of weather, accidents, and incidents on traffic performance. This approach to modern traffic engineering by reliability is receiving increased attention in several countries worldwide.
To increase reliability of motorway traffic a bundle of actions might be taken which go far beyond the traditional approach of traffic engineering. Some solutions as examples for technical approaches can be: traffic adaptive speed control, ramp metering, overtaking restrictions for trucks, etc. However, in many cases organizational approaches become far more efficient than technical solutions. Examples are: demand management, intelligent workzone scheduling, variable tolls, changes of rules for the police to clear places of accidents and incidents, penalties for drivers or vehicles owners who block the road by incidents or accidents, and others. Moreover, education of drivers towards smooth traffic behaviour may improve the reliability under traffic demand levels near capacity. Also everything which helps to avoid accidents supports reliability since an accident is always a major source of impediments to traffic flow.
Bio: Prof. Brilon graduated from Karlsruhe University Germany, where he also got his phd. He started his career as an official with the state highway administration in Germany where he finally worked at the state ministry of transportation in Stuttgart, Germany. He got his professorship at the Ruhr-University Bochum in 1983. He teached traffic engineering and transportation planning until 2009. During his university career he was conducting many research projects, mainly on topics of
motorway traffic analysis, unsignalized and signalized intersections and other areas. He was and is still involved in several technical committees in Germany and in the US. Among others, he was member of the scientific advisory board to the federal minister of transport. At the moment he is still chairman of the committee for the development of the next German Highway Capacity Manual.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
26/03/2013 @ 18:00 room CM 1 1

The Fierce Urgency of Now

Raymond S Bradley is a University Distinguished Professor in the Department of Geosciences and Director of the Climate System Research Center at the University of Massachusetts, Amherst. He also co-directs the Northeast Climate Science Center of the U.S. Dept of Interior.
His research interests are in climatology and paleoclimatology, with a particular focus on how climate has changed since the last ice age, and the causes of climate variations. He has written or edited twelve books on climatic change
Ray Bradley has been an advisor to various government and international agencies, including the U.S., Swiss, Swedish and U.K. National Science Foundations, the Arctic Research Consortium of the U.S., U.S. National Oceanic and Atmospheric Administration (NOAA), the National Research Council and the International Geosphere-Biosphere Program (IGBP).

Since the beginning of the Industrial Revolution in the 18th century, the earth has undergone unprecedented changes. But in the last few decades there has been a rapid acceleration of humanity’s impact on our environment, driven by a world population that now exceeds 7 billion people. Humanity’s impact can been seen in even the remotest parts of the planet, exceeding the natural limits within which life on earth has evolved over the past few million years, at least. Exploitation of natural resources and unregulated disposal of waste products into the “global commons”—our oceans and atmosphere—poses serious challenges for the future. We must adopt solutions that lead to a more sustainable future, while raising the standard of living of those who are impoverished and increasingly vulnerable to environmental instability. This requires foresight and leadership at an international level, qualities that are sadly lacking in the political leaders of today.

Organized by Chaire Landolt & Cie @ l'EPFL
28/03/2013 @ 12:15 room GC C330

Are the Frail destined to Fail? Assessing the Collapse Risk of Existing Structures

Prof. Bing Li

The vulnerability of conventional non-seismically detailed reinforced concrete building structures due to loss of columns has been emphasized during the past years. The lack of corresponding experimental tests has led to gap in the knowledge for the design of reinforced concrete structures to mitigate the potential of progressive collapse due to loss of ground storey column by extreme loading. This talk provides an overview of assessing the Collapse Risk of Singapore's Existing Reinforced Concrete Frame Structures. These investigations attempt to gain understanding on the behavior of reinforced concrete substructures when subjected to the loss one of its ground column scenarios in order to improve the state of the art of protective design. The results of this study can be used to form a basis for the understanding of the behavior of RC structures for progressive collapse.

Bio: Dr Bing Li is an Associate Professor and Director, Natural Hazards Research Centre (NHRC) at Nanyang Technological University (NTU), Singapore. He received his Ph.D in Civil Engineering from the University of Canterbury, New Zealand and has extensive experience in design practice with top ranked international consulting firms for six years in Hong Kong before joining NTU in 1999. His research interests are in reinforced concrete and precast concrete structures, particularly in design for earthquake and blast resistance.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
11/04/2013 @ 12:15 room GC C330

Market-based approaches applied to transportation issues: the Heavy Vehicle Fee - a Swiss success story

Ms Franziska Borer Blindenbacher

Various countries have meanwhile adopted market incentives to meet transport needs in an economically efficient way. The seminar will touch on different types of approaches for financing passenger and freight transportation, and for addressing transportation-related externalities. There will be a special emphasis on the unique Swiss Heavy Vehicle Fee (HVF), which will serve as an example of the practical and political issues that need to be addressed in order to implement sustainable national transportation policies. The objectives of this seminar are to encourage students to familiarize themselves with a range of transportation and related environmental, social and economic policy issues and to develop an understanding of the complexity, inter-connection and potential resolution of some of these issues.

Bio: Franziska Borer Blindenbacher is an economist and works as an international consultant and teacher in the fields of transport, spatial planning and the environment. She also works part-time as a scientific adviser for the Swiss Federal Office for Spatial Development (ARE). Among her clients in the public and private sector are the Canadian, the US as well as the Swiss Ministry of Transportation, the Swiss Association for Public Transportation, PostAuto Switzerland, the Institute for Transportation and Development Policy (ITDP) in New York and Washington DC, and the European Institute for Sustainable Transport (EURIST) in Hamburg. Ms Borer Blindenbacher was part of the team that developed and implemented the distance- and emission-related heavy vehicle fee (HVF) in Switzerland as well as the federal coordinating transportation infrastructure and spatial development in metropolitan areas. Ms Borer Blindenbacher is the author of various publications in the field. Among them the case study From an Integral Transport Concept to Financing Urban Transit - The Swiss Approach (2008). Further the Study of Methods of Road Capital Cost Estimation and Allocation by Class of User in Austria, Germany and Switzerland (2007). She teaches at different national and international academic institutions such as the George Washington University in Washington DC and the University of Applied Sciences of Eastern Switzerland (HSR) in Rapperswil.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
18/04/2013 @ 12:15 room GC C330

Macro-element modelling of masonry walls. Modelling issues, recent developments and applications

Prof. Andrea Penna

Equivalent frame modelling is becoming a standard approach for the analysis of the lateral behaviour of masonry walls. This approach is based on the use of macro-elements, i.e. 2-node elements simulating the response of structural members (masonry piers and spandrels). Depending on the analysis method (e.g. pushover or time-history), the degree of accuracy and other specific aspects, several macro-element models can be suitable for simulating the seismic response of masonry buildings. Among these, a mechanics based macro-element capable of modelling the nonlinear interaction of the in-plane flexural and shear response will be illustrated in detail, together with some sample applications showing the simulation of the experimental response of structural members and entire building models. Some recent upgrades of the macro-element will also be presented showing new potential fields of application of the refined model.

Bio: Dr. Andrea Penna is assistant professor at the Dept. of Civil Engineering and Architecture of the University of Pavia and member of the Masonry Structures section of the European Centre for Training and Research in Earthquake Engineering. He graduated in Structural Civil Engineering at the University of Genoa (1998) and obtained a Ph.D. in Earthquake Engineering from the Politecnico of Milan (2002). After a post-doctoral fellowship in Structural Engineering at the Dept. of Structural and Geotechnical Engineering of the University of Genoa, he became researcher at the EUCENTRE (2003-2011).
His research activity has been mainly addressed to numerical modelling of masonry structures, seismic response evaluation of existing buildings, seismic risk analysis and experimental research activities on the in-plane cyclic response of full scale masonry piers, the in-plane and out-of-plane response of masonry infill walls in r.c. frame structures, mechanical characterization tests and shaking table testing of masonry buildings (with different strengthening solutions) and architectural components.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
02/05/2013 @ 12:15 room GC C330

You Can Lead Travellers to the Bus Stop, But You Can’t Make Them Ride

Prof. Joan Walker

Latent modal preferences, or modality styles, are defined as lifestyles built around the use of a particular travel mode or set of travel modes. Traditional models of travel mode choice assume that (1) that all individuals are aware of the full range of travel modes at their disposal and make a rational mode choice based on level-of-service and (2) individual modal preferences are characteristics of the individuals that are exogenous to the choice situation and stable over time. Though these assumptions simplify the model, they risk overlooking the impact of more deeply entrenched individual variations in modal preferences.

This talk presents a latent class choice model (LCCM) that allows modal preferences to be endogenous to the choice situation and variable across individuals. The model is applied to analyze modality styles and travel mode choice behavior of 25,000 people in the San Francisco Bay Area. The study identifies six distinct modality styles in the sample population that differ in terms of their taste parameters and choice sets. Most notably, nearly a third of the sample is found not to consider any mode other than auto. Results show that an individual’s value of time is sensitive to the level-of-service, and an increase in congestion can induce decision-makers to lower their value of time. Findings further reveal that incremental improvements in the transportation system result in far smaller changes in travel behavior than predicted by traditional models; what is needed is a dramatic change to the transportation system that forces individuals to reconsider their modality styles. This is joint work with UC Berkeley doctoral candidate Akshay Vij.

Bio: Joan Walker’s research focus is behavioral modeling, with an expertise in discrete choice analysis and travel behavior. She works to improve the models that are used for transportation planning, policy, and operations. Professor Walker joined UC Berkeley in 2008 in the Department of Civil and Environmental Engineering and as a member of the interdisciplinary Global Metropolitan Studies initiative. She received her Bachelor's degree from UC Berkeley and her Master's and PhD degrees from MIT. Prior to joining UC Berkeley, she was Director of Demand Modeling at Caliper Corporation and an Assistant Professor at Boston University. She is Chair of the Transportation Research Board’s Committee on Transportation Demand Forecasting, an Associate Editor of Transportation Science, and a recipient of the Presidential Early Career Award for Scientists and Engineers (PECASE).

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
16/05/2013 @ 12:15 room GC C330

Statistics and Neural Networks: Differences, Similarities, and Why Should transportation researchers be Interested?

Prof. Matthew G. Karlaftis

In the field of transportation, data analysis is probably the most important and widely used research tool available. In the data analysis universe, there are two 'schools of thought'; the first uses statistics as the tool of choice, while the second - one of the many methods from - Computational Intelligence. Although the goal of both approaches is the same, the two have kept each other at arm's length. Researchers frequently fail to communicate and even understand each other's work. In this presentation we discuss differences and similarities between these two approaches, attempt to provide a set of insights for selecting the appropriate approach, and present three cases studies from transportation research that compare the two distinct approaches on the same set of data.

Bio: Matthew G. Karlaftis, Ph.D. is an Associate Professor at the National Technical University of Athens. He holds BSc and MSc degrees in Civil Engineering and an MSc in Mathematics from the University of Miami (USA), and a Ph.D. in Civil Engineering from Purdue University. Prof. Karlaftis has long and significant research experience on a variety of research areas related to transportation planning, transit operations, transportation economics and quantitative methods. Prof. Karlaftis has participated in many national and European research projects and is the co-author of an international best selling book on transportation statistics and econometrics, book chapters, peer reviewed journal papers and papers in conference proceedings. He is Editor-in-Chief for Transportation Research part C, European Editor of ASCE’s Journal of Transportation Engineering, Associate Editor of ASCE’s Journal of Infrastructure Systems, and an editorial board member for eight other journals. He has received the Fulbright Scholar Grant (2006-2007), the Walter L. Huber Civil Engineering Innovative Research Prize (2005, by the American Society of Civil Engineers), the ABJ80 Best Paper Award for 2009 by TRB, and the 2011 ASCE State-of-the-art Award.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
23/05/2013 @ 12:15 room GC C330

Axially suspended decks for road and railway bridges - Example: Railway bridge, Sado crossing

Prof. Antonio Reis

The seminar will cover from some basic design concepts and options for this bridge deck typology, to some more advanced aspects related to the main issues related to static analysis and aerodynamic stability. Simple voided slab decks to single cell or multicell box girders or even spatial composite truss decks, may be adopted with an axially suspension scheme in cable stayed and bow string arches. The deck torsional stiffness is of course the main issue to control the static and dynamic responses under traffic and wind loadings. A variety of design examples are discussed.

Short Bio: Antonio J. REIS got his MS from IST Lisbon and his PhD from Univ. Waterloo, Canada. He pursued both an academic and professional career as structural engineer. He joined the Technical University of Lisbon in 1977 as assistant Prof. and became full Prof. in 1985. His research and teaching activities in are in the domain of Bridges and Design of Structures. Most of his research work at the University has been on steel and composite bridges and stability of structures. He has more than 130 technical and scientific publications in proceedings of international congresses and journals and is the co-author of two books.
In parallel, in 1980, he founded his own design office, GRID consulting engineers Ltd. He is responsible for the design of a variety prestressed concrete, steel and composite bridges, including cable stayed bridges and bowstring arches and the strengthening of many bridges including suspension bridges. He also has designed other special structures including several long span roofs for football stadiums. GRID projects and consultancy cover 16 different countries in Europe, Africa, Asia and South America. In 2006 was nominated “ Comendador da Ordem de Mérito” by the President of the Portuguese Republic.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
30/05/2013 @ 12:15 room GC C330

Developing Ductile Connections in Steel Bridges for Seismic Design

Prof. Mervyn Kowalsky

The basic premise of seismic design allows structures to deform inelastically in large earthquakes as long as the deformation capacity of the structure is sufficiently large when compared to the deformation demands imposed by earthquake excitation. In the case of steel bridge structures, such provisions for ductility are difficult to achieve, especially when using welded connection between bridge columns and cap beams. In this seminar, a new connection design has been proposed which aims to address the shortcomings of traditional welded connections in steel bridges. Through the use of large scale testing, finite element analysis, and shake table testing, the connection has been shown to significantly improve the performance of steel bridges. Furthermore, the connection is rather simple to construct while also cost efficient.

BIO: Dr. Mervyn Kowalsky is a Professor of Structural Engineering at North Carolina State University and a registered Professional Engineer in the state of North Carolina. His research, which is largely in the area of seismic analysis and design of reinforced concrete systems and development of alternative seismic design methods has been supported by the National Science Foundation, the State Departments of Transportation of Alaska and North Carolina, the US Army Corps of Engineers, and several industrial organization. He has published numerous articles in international journals and is co-author of a textbook on Displacement-Based Seismic Design.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
26/09/2013 @ 12:15 room GC B331

Interfaces and indicators for collaboratively developing urban quality across scale

Dr. Ulrike Wissen Hayek

Currently, great efforts are taken to develop new strategies and guidelines for transforming agglomerations into urban patterns of high quality. These new approaches need to facilitate collaborations between science and a variety of public and private stakeholders to come up with robust solutions. They should enable them to make decisions on urban development taking into account multiple dimensions, alternative development possibilities, and performance indicators at multiple planning scales. A major challenge is to consolidate the information suitable to inform policies and local actors to create better understanding of human-environment interaction. A collaborative urban planning platform comprising suitable instruments for supporting this task is presented, which is set up in the scope of the NRP 65 project “Sustainable Urban Patterns”. Focus is laid on an approach that allows for cross-scale analysis of urban development scenarios addressing economic, social and environmental aspects of urban quality. Practical interfaces for implementing an integrated behavioural and transport modelling system in transdisciplinary planning processes are illustrated. The indicators calculated based on the modelling output provide evidence on possible urban pattern’s potential quality supporting social equity and liveability. Overall, the presented approach has high potential to organize a future oriented mutual sustainability learning and capacity building among stakeholders, planning experts and scientists.

Bio: After an apprenticeship as landscaper Dr. Ulrike Wissen Hayek studied and made her diploma in landscape architecture and planning at the Technical University of Munich (Germany) in 2000. Then she worked from 2001 – 2002 at the company GeoVille in Innsbruck (Austria) as GIS expert. In 2007 she finished her PhD on “Virtual landscapes for public participation” at the ETH Zurich. In 2008 Dr. Ulrike Wissen Hayek became Research Fellow and Lecturer, and since 2012 she is Senior Research Fellow and Lecturer at the Chair Planning of Landscape and Urban Systems (PLUS/ETHZ) of Prof. Adrienne Grêt-Regamey. Her key research focuses on the assessment and management of landscape change, GIS-based 3D landscape visualization, participative planning methods and transdisciplinary action research. She manages several projects on developing, applying and iteratively enhancing 3D visualizations for supporting stakeholders on spatial planning tasks. Furthermore, she was project manager of the NRP 54 project “Scenarios for sustainable settlement and infrastructure development in Switzerland (2005 – 2030)”. In the scope of the NRP 65 “New Urban Quality” she manages the project “SUPat – Sustainable Urban Patterns” focusing on the development of instruments and processes for a collaborative urban platform.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
10/10/2013 @ 12:15 room GC B331

Enabling Accelerated Construction of Bridges in California with Seismic Requirements

Prof. Sri Sritharan

The presentation will focus on an integral bridge pier system consisting of concrete columns, precast concrete girders, and concrete cap beams that is being investigated to facilitate accelerated bridge construction (ABC) in seismic regions of California. Despite their advantages, bridges with precast components are not currently favored due to their design approaches resulting in costly solutions and an expectation that these bridges will produce poor seismic performance. Using a combination of large-scale tests and analytical investigations, the seismic behavior of both the connections between the precast girders and cap beams as well as the overall bridge systems are studied. It will be demonstrated during the presentation that the current design specifications adopted by the California Department of Transportation (Caltrans) for this precast girder bridges are unnecessarily conservative, thus making them less cost competitive in comparison to the cast-in-place alternative. It will be further shown that the outcomes of this research project will not only enable use of precast components in bridges of California, but also make them cost effective while ensuring their dependable seismic performance.

Short Bio: Dr. Sri Sritharan is the Wilson Engineering Professor of the Department of Civil, Construction and Environmental Engineering at Iowa State University and is currently a visiting professor at the EESD laboratory of EPFL. Sri’s research expertise includes earthquake-resistant design of structures, precast structural systems, soil-foundation-structure interaction, and ultra-high performance concrete. Sri is an active member of several professional societies and organizations including the American Concrete Institute (ACI), Precast/Prestressed Concrete Institute (PCI) and Transportation Research Board (TRB), and is the current chair of the ACI’s Committee on Earthquake-Resistant Concrete Bridges.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
16/10/2013 @ 17:30 room Forum RLC

Le Projet "Rivages": Quand Bernard Stamm et l'EPFL s'unissent pour mieux comprendre les océans - Landolt Public lecture

P. Landolt, P. Gillet, P. Vuilliomenet, B. Stamm

Derrière l’esprit purement scientifique des chercheurs de l’EPFL se cache souvent une âme d’aventurier. Ce n’est donc pas un hasard si l’Ecole polytechnique fédérale de Lausanne s’investit, toujours avec enthousiasme, dans des projets innovants doublés de défis stimulants.
Soutenir Bernard Stamm et le projet Rivages, dans le challenge d’un tour du monde en solitaire lors du Vendée Globe 2012, s’inscrit naturellement dans cette ligne. Au travers des collaborations avec les experts de son équipe technique, les chercheurs de l’Ecole ont participé à l’amélioration des performances de son 60 pieds IMOCA. Autre défi lancé par Bernard Stamm, faire en sorte que cette recherche de performance s’inscrive dans une logique de développement durable et écoresponsable. Le bateau allant voguer dans des eaux peu fréquentées, tels que les fameux 40ème rugissant et le 50ème hurlant, il offrait une opportunité unique aux scientifiques de faire des relevés environnementaux qui viennent compléter les bases de données existantes.
Au travers de quelques exposés et d’une vidéo, les intervenants montreront les motivations de cette collaboration, les défis technologiques et les questionnements scientifiques, mais aussi les aléas rencontrés sur le terrain par le navigateur.

Organized by Chaire Landolt & Cie @EPFL http://chaire-landoltetcie.epfl.ch/
17/10/2013 @ 12:15 room GC B331

Structural Behavior of High Performance Steel Bridges

Dr. Lan Duan

Compared with conventional steels used in bridge construction, high performance steel (HPS) has superior properties in terms of strength, weld ability, fracture toughness and weathering characteristics. These material properties lead to very competitive costs and low carbon release in the whole life span of HPS bridges. This presentation focuses on the high performance steel HPS 485W, with a nominal yield strength of 485MPa. Studies are conducted on fracture control, fatigue resistance design, fabrication technology, structural strength and stability. With respect to fracture control and fatigue design, experimental campaigns were conducted, comprising impact toughness (CVN) tests, ductile fracture toughness (JIC) tests, crack tip opening displacement (CTOD) tests and fatigue crack growth rate (da/dN) tests. In addition, the flexural and shear behavior of hybrid high performance steel beams were investigated by means of experimental tests, finite element calculations and theoretical analyses. The study addresses the HPS beam’s capacity, ductility, failure mode and stability behavior. Based on these research results, the costs and performance of high performance steel plate girder bridges and traditional steel plate girder bridges are compared.

Bio: Lan Duan is a lecturer at the Bridge Engineering Institute, Highway School, Chang’an University in China. She received her Ph.D. in Civil Engineering from Chang’an University in China. Lan Duan works research focuses on high performance steel bridges, fatigue and fracture of steel bridges, and steel-concrete composite bridges. She has participated in the following research programs: “Static and fatigue behavior study for high performance steel structure”, “Key technology study for high strength steel bridge”, “Capacity and remaining life calculation for old steel bridge” and “Orthotropic steel bridge deck fatigue mechanics and remaining fatigue life evaluation study”.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
24/10/2013 @ : room Forum Rolex

Open Access conferences, Thursday October 24, 2013. 10 a.m to 7 p.m.

Pr Benoît Deveaud-Plédran, Dean of Research, EPFL
Catriona McCallum, Advocacy Project Manager, PLOS.
Dr Meloney Bartlett, Executive Director, Royal Society of Chemistry (RSC)
Pierre Devaud (MSc) et Dr Alain Borel, Scientific Librarians, Bibliothèque de l’EPFL / Infoscience (EPFL)
Dr Xenia van Edig, Business Development, Copernicus
Dr Dagmar Meyer, Policy Adviser, European Research Council (ERC), (to be confirmed)
Dr Daniel Höchli, Director of the Administrative Offices, Swiss National Science Foundation (SNSF)
Dr Kamila Markram, Co-founder, Chairman and Chief Executive Officer, Frontiers
Pr Hilal Lashuel, Associate Professor, EPFL

In the frame of the Open Access Week, the EPFL library is pleased to invite you to the event « Open Access: authors, publishers, investors and institutions for the dissemination of the scientific research's results » that will take place at the Forum Rolex Learning Center, campus EPFL on Thursday October 24, 2013. Free entrance.

For the past 10 years, the Open Access movement has been defending the principle of free accessibility to the scientific literature for everyone.

Who are the Open Access’ actors ?
Which are the economic models and their stakes ?
Why publish in Open Access ?
How do institutions pay for publication in open access ?

Those questions will be addressed from various points of view (publishers, academic institutions, investors and authors) through conferences.

Register through the online form!

We are looking forward to meeting you on Thursday October 24!

Organized by Bibliothèque de l'EPFL
24/10/2013 @ 12:15 room GC B331

Seismic response of monumental masonry buildings

Prof. Stefano Podestà

The recent Italian earthquakes (Abruzzo 2009 and Emilia 2012) highlighted once more the high seismic vulnerability of existing masonry buildings, also in the case of cultural heritage structures. The evaluation of the seismic response of historical monumental buildings calls for an interdisciplinary approach able to take into account different type of input that characterize the fundamental phase of knowledge. Only if we are able to translate these data into a mechanical model it is possible to design reliable seismic improvement interventions.
The recent Italian Guide Lines for the evaluation and reduction of seismic vulnerability of cultural heritage (Directive PCM, February 2011) represent a useful tool to this aim.
It will be demonstrated during the presentation that the current design specifications adopted by the Italian Technical Code, if they were applied in a preventive way on churches damaged by the Abruzzo 2009 or Emilia 2012 earthquakes, they would have reduced the damage level and avoided some structural collapses. It will be further shown that the economic costs of preventive retrofitting interventions, in particular for monumental buildings, are of a lower order of magnitude in comparison with the costs that amount after a seismic event.

Short Bio: Dr. Stefano Podestà is Assistant Professor of Structural Engineering of Department of Civil, Chemical and Environmental Engineering at the University of Genoa (Italy) and he is currently a visiting professor at the IMAC laboratory of EPFL. His specific fields of research regard different topics: the monitoring and diagnosis of existing buildings; the definition of retrofit intervention strategies; the individuation of methodologies finalized to the seismic risk analysis at territorial level. Recently he is providing support to the Italian Ministry of Cultural Heritage and Activities, for the design of the Informative System for the evaluation of seismic risk of cultural heritage. He is author of more than 130 scientific publications with national and international relevance. He is currently lecturer for Timber Structure Design (CL5 – Bachelor degree in Civil and Environmental Engineering) and Building Retrofit (CL5 – Bachelor degree in Construction Engineering) courses.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
30/10/2013 @ 12:15 room GC B331

Defining the concept of partial observability in network sensor location problems

Prof. Francesco Viti

The quality of information available on a network is crucial for different transportation planning and management applications. The problem of where to strategically obtain this information has long tradition, and normally can be subdivided into observability problems, focusing on the topological properties of the network, and flow-estimation problems, where (prior) information of traffic states, and/or the specification of which type of application is making use of the sensor data, is needed. This talk provides a broad view of the two categories, and focuses on the development of a new methodology and an intuitive metric for assessing the information quality of a set of sensors in a network in case of partial observability, i.e. when not all sensors characterizing full information coverage solutions are available. This become very useful if one considers that even in small sized networks the solution for full observability requires an exceedingly large amount of sensors. We show the natural interpretation of this new methodology both on toy networks and on a real-sized network, to show how the method performs and selects the most informative links where to install the sensors. Analysis of partial observability solutions shows that the local search algorithm succeeds in finding the links that contain the largest deal of information in a network, and to classify families of full observability solutions.

Bio: Prof. Francesco Viti (UL) is Associate Professor and holds the chair of the Transportation Engineering Lab at the Faculty of Science and Technology of the University of Luxembourg. His research covers a broad range of topics from travel behavior to multimodal network modeling and advanced data collection techniques, carried on at both the University of Luxembourg and at the Katholieke Universiteit Leuven. He teaches Traffic Planning and Management, Transport and Mobility and Infrastructure Design at the Bachelor of Engineering and the at Masters of Energy and Environment and Civil Engineering, and Supply Chain Management at the Master of Mechanical Engineering and as guest lecturer at the Master in Traffic, Logistics and ITS at the Katholieke Universiteit Leuven. He also acts as Expert for the European Commission and as advisor for various EU-funded projects. He has over 100 scientific publications with about 30 articles in journals with Impact Factor.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
07/11/2013 @ 12:15 room GC B331

Form-finding for design of compression shells, tensile membranes and tensegrities by means of the Multiple Force Density Method

Prof. Enrique Hernández Montes

Form-finding of suitable tension-only or compression-only structures has been a significant engineering and scientific problem in the past century. Mechanical analogies as well as numerical procedures have been developed in the past leading to a number of solutions. Some cases, as double domes, remain however complicate to be obtained. In this seminar, it is presented an innovative approach to this problem based on topology and on the multiple force density method. This approach is shown to open a new window to the concept of designing tension-compression structures. The method is simple, intuitive and easy to understand.

Bio: Enrique Hernández Montes is full professor of Concrete Structures at the University of Granada (Spain), where he obtained his diploma and PhD in 1992 and 1995 respectively. He has been visiting professor at Politecnico di Milano (Italy). His main research activities are found in the field of Structural Engineering, particularly earthquake engineering, concrete structures, steel structures, form-finding and conceptual design. He is also in charge of teaching the subject Ethics and Aesthetics in Engineering at the University of Granada.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
15/11/2013 @ 10:15 room ME C2 405

Steam-cracking: an evergreen of the chemical process industry

Guy B. Marin

My lecture will focus on the thermal conversion of fossil or renewable feedstocks to olefins.

Steam cracking can be described by considering a limited number of elementary reaction families not only for fossil but also for renewable feedstocks. Group contribution methods can be applied to calculate the corresponding kinetic parameters. The group contributions follow from a data base obtained by high level ab initio calculations involving representative molecules and reactions. Based on this single-event microkinetic (SEMK) methodology a reasonable agreement with pilot and industrial data was obtained for ethane steam cracking.

SEMK requires the characterization of a feed stock in terms of types of molecules. Both fossil or renewable feedstocks typically consist of a considerable amount of types of molecules. The available information is limited to commercial indices corresponding to. So-called molecular reconstruction methods use macroscopic properties such as density and boiling point traject to obtain a characterization of the feedstock in the terms required. Of course they are based on a training set. The latter can be obtained by a GCxGC analysis of typical feeds.

Process optimization and innovation not only involves feed stocks and reactor technology but should also account for up- or downstream units like the Transfer Line Exchanger (TLE), the convection section and the interaction between the furnace and the reactor coils. These aspects are discussed in the last part of my lecture.My lecture will focus on the thermal conversion of fossil or renewable feedstocks to olefins.

Process optimization and innovation not only involves feed stocks and reactor technology but should also account for up- or downstream units like the Transfer Line Exchanger (TLE), the convection section and the interaction between the furnace and the reactor coils. These aspects are discussed in the last part of my lecture.

Organized by Laboratoire d'Automatique (LA EPFL)
21/11/2013 @ 12:15 room GC B331

Mixing in gravity currents

Prof. Claudia Adduce

Gravity currents are flows driven by a density difference mainly in the horizontal direction. The agents causing the density difference include temperature differentials, dissolved and suspended materials. Laboratory experiments and numerical simulations of gravity currents are performed. Experiments investigating mixing in a density-driven current flowing down a sloping bottom, in a rotating homogenous fluid are discussed. A systematic study spanning a wide range of Froude and Reynolds numbers is conducted and different flow regimes are observed. The entrainment parameter is found to be dependent not only on Fr, as assumed in previous studies, but also on Re. Several experiments simulating unsteady gravity currents moving on flat and up-sloping beds are performed. A two-layer shallow water model accounting for the entrainment and simulating unsteady gravity currents is developed. The developed shallow-water models with and without entrainment are also compared, showing a better agreement when mixing is accounted for. Laboratory experiments and shallow model simulations are in good agreement.

Bio: Claudia Adduce is Assistant Professor with tenure at the Department of Engineering of the University Roma Tre, Italy. She completed her PhD at the University Roma Tre and she worked at the Department of Physical Oceanography of Woods Hole Oceanographic Institution (USA). She is Professor of Environmental Hydraulics for Civil Engineers at the University Roma Tre. Her research focuses on: mixing due to gravity currents, eddies interaction with seamounts and islands, local scouring downstream of hydraulic structures, sloshing of stratified fluids.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
28/11/2013 @ 12:15 room GC B331

Using macroscopic models to study large-scale transportation systems

Prof. Vikash Gayah

Abstract: In studying transportation systems, the general trend is towards developing increasingly detailed models that can describe the behavior of individual components very well. However, although these detailed models might be able to predict how specific components of a system will behave, there are several drawbacks when applying these to study large-scale systems. Detailed models generally require a tremendous amount of data, involve complex numerical methods, and can lead to a false sense of precision due to inaccuracies in the input values. Furthermore, it is often difficult to develop meaningful insights using detailed models. Instead, it might be more beneficial to use macroscopic models that only describe the behavior of individual components approximately, relying on fewer pieces of information. These models eschew detail in favor of computational simplicity and the development of meaningful insights, and are well-suited to studying large-scale transportation systems. This talk will discuss the use of macroscopic/parsimonious models, as well as potential domains of application when compared to detailed models. Examples will be given of how these models can be applied to both a logistics and urban transportation problem.

Bio: Vikash V. Gayah is an Assistant Professor in the Department of Civil and Environmental Engineering at the Pennsylvania State University. He received his Ph.D. in Civil and Environmental Engineering with an emphasis in transportation systems at the University of California, Berkeley. He also received a B.Sc. (2005) and a M.S. (2006) in Civil and Environmental Engineering at the University of Central Florida. His research interests are in transportation network dynamics, traffic flow theory, traffic safety and urban mobility. Dr. Gayah serves as a member of the Transportation Research Board’s committee on Traffic Flow Theory and Characteristics and serves as a reviewer for several top transportation journals.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
05/12/2013 @ 12:15 room GC B331

Uncovering the Controlling Mechanisms of Crack Growth to Improve Failure Predictions

Prof. Derek Warner

In the last century, human understanding progressed to a point where the physical laws at the foundation of many everyday experiences became known. In this century we are faced with the challenge of utilizing this fundamental knowledge to improve our ability to predict, control, and create from the world around us. In many instances, the central challenge involves spanning the vast divide between the macroscopic scale that we interact with and atomic scale where the fundamental physical laws operate.
As our understanding of the connection between the macroscopic and atomic scales continues to strengthen, structural engineering will certainly benefit. For example, a key challenge is to predict the response of structures that have been subjected to loads and/or environments for which experimental data does not exist. In this scenario, one must use a mechanical model to interpolate or extrapolate from the experimental data that is available. The truer the mechanical model is to the underlying physics that govern the response, the greater the chance that the model will be able to provide a meaningful prediction extending beyond the experimental data.
In this spirit, our group works to better understand the mechanics and mechanisms that govern the crack growth process. This seminar will specifically focus on the ductile crack growth processes in a structural aluminum alloy. In this case, crack growth is governed by the nucleation, growth, and coalescence of microvoids. Using experimental observations, insights from lower-scale atomistic modeling, and finite element simulations, we model these processes to predict material failure without artificial fitting parameters. The predictions are then critically examined in light of experimental test results.

Bibliographical Sketch: Derek Warner is currently a Visiting Professor in the Computational Solid Mechanics Laboratory at EPFL. He is on sabbatical leave from his Associate Professor appointment in the School of Civil and Environmental Engineering at Cornell University. Prior to this he was a Postdoctoral Research Associate in the Division of Engineering at Brown University, where he worked in the Mechanics of Solids Group. He completed his Ph.D. in Mechanical Engineering at Johns Hopkins University in 2006. Derek’s overall research effort is aimed at understanding the connection between microscopic physical phenomena and the macroscopic deformation and failure of engineering materials by coupling cutting-edge computing technologies with state-of-the-art simulation techniques.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
09/12/2013 @ 12:15 room SV 1717A

Gamma-Secretase: basic biology and therapeutic potential in Alzheimer’s disease

Prof. Patrick Fraering

Alzheimer’s disease (AD) is the most common form of dementia, for which no efficient treatment exists. Gamma-Secretase is a multi-subunit integral membrane protease complex that controls a wide variety of cellular and biological processes by regulating intramembrane proteolysis of proteins, including the Notch receptor and synaptic cell adhesion molecules. By catalyzing the final cleavage of the amyloid-beta precursor protein (APP), gamma-secretase is responsible for the neuronal production of the amyloid-beta peptides (A beta), the accumulation of which causes AD. As such, gamma-secretase has emerged as a key target to treat AD. Our group has developed new tools and systems that provided groundbreaking structural and functional insights into gamma-secretase and the intramembrane proteolysis of APP and A beta production. I will show how we used these to understand the genotype to phenotype conversion in early-onset familial AD caused by mutations in APP or in PS1, the catalytic subunit of gamma-secretase. Next, because clinical studies with gamma-secretase inhibitors (GSIs) have revealed severe side effects mainly attributed to impaired Notch signaling, we developed new strategies to selectively reduce A beta production without affecting other gamma-secretase functions. I will discuss the concepts, results and promises of our approaches, including small molecule gamma-secretase modulators (GSMs), APP-substrate neutralizing monoclonal antibodies, and the identification of new endogenous modulators of gamma-secretase. Together, our findings greatly contribute to efforts aiming at solving a major medical and socio-economic problem.

Organized by SV Faculty
12/12/2013 @ 12:15 room GC B331

Coupled Osmotic and Swelling Phenomena within Sodium Bentonites for Pollutants Containment Barriers: Theoretical Aspects and Potential Applications

Prof. Mario Manassero

Sodium Bentonites are clayey soils characterized by a high specific surface and a permanent negative electric charge on the solid skeleton. Their increasing use as hydraulic and contaminant barriers for landfills and soil remediation applications, including the final disposal of nuclear waste, needs to be supported by adequate theoretical modeling of their mechanical behavior and transport properties, in order to assess the expected performance with particular reference to the long term.

To this end, a theoretical framework has been proposed in order to derive constitutive equations for the coupled chemical-hydraulic-mechanical behavior of sodium bentonites. Their solid phase is assumed to be constituted by montmorillonite lamellae having a slit-like geometry, which can be aggregated to form the so-called tactoids. Chemical equilibrium is assumed to be established between the bulk external electrolyte solutions and the internal pore solution at the macroscopic scale, so that the hydraulic pressure and ion concentrations can be evaluated through the Donnan equations. Water and ion transport is described at the pore scale through the generalized Navier- Stokes equation and the generalized Nernst-Planck equations, respectively. Mechanical behavior is modeled taking into account inter-granular contact stresses and electro-static attraction and repulsion forces.

The proposed theoretical approach has been applied to interpret a series of experimental results from many authors (Malusis and Shackelford, 2002; Malusis et al., 2013; Dominijanni & Manassero, 2011 and Dominijanni et al. 2012 among others) and a number of laboratory tests on natural, pretreated and polymer-modified bentonites carried out at Politecnico di Torino using an osmotic cell specifically designed and setup for this research program.

Bio: Mario Manassero has been professor of Geotechnical Engineering at Politecnico di Torino since 2002. He received his Ph.D. from the same university in the 1987. He is Chairman of Technical Committee (TC) no. 215 "Environmental Geotechnics" of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE)(2001-2014). His main research activities are devoted to the geotechnical characterisation of soil deposits using in-situ tests, soil improvement and reinforcement methods, containment systems for landfills and polluted subsoils, the mechanical behaviour of municipal and industrial wastes, the chemo-physical interaction between pore fluids and the solid skeleton, multiphase coupled flows and associated transport phenomena.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
19/12/2013 @ 12:15 room GC B331

Rocking as a Seismic Isolation Technique for Modern Bridges

Prof. Elias Dimitrakopoulos

Conventional seismic (code-based) design focuses on accommodating structural deformation, during an earthquake excitation, but accepts the prize of "sustainable" damage after a major earthquake. Recently, the concept of re-centering structures, which hinge on (some degree of) rocking motion, as a means of seismic isolation is proliferating. Rocking isolation allows the (bridge) piers to uplift and pivot, as a means to relieve (isolate) the structure from deformation, stresses and hence damage. This talk outlines the discrete evolution phases of the civil engineering rocking structures (with emphasis on bridges) and highlights peculiar features of rocking dynamics. It offers a description of the rocking response which elucidates the behaviour of rocking structures under excitations of different intensity, despite the nonlinear and nonsmooth nature of the rocking dynamics. Further, the talk presents an analytical investigation of the benefits of using viscous damping to limit the rocking motion. Finally, the talk proposes a methodology to derive equivalence between the archetypal rocking block and more complicated/realistic rocking structures.
short bio: Dr. Elias Dimitrakopoulos is an Assistant Professor at the Hong Kong University of Science and Technology since Fall 2011. He received his Civil Engineering diploma, Master of Science in Seismic Engineering, and Doctoral Degree, from the Aristotle University of Thessaloniki (AUTH) in Greece. In addition, he was a Post-Doctoral researcher at the University of Cambridge U.K., at the Department of Engineering. Dr. Dimitrakopoulos’ research interests lie in the areas of earthquake engineering, structural dynamics and bridge engineering with emphasis on nonlinear and nonsmooth phenomena.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
07/03/2014 @ 12:15 room GC B330

Flexibility in Engineering Design

Prof. Richard de Neufville (MIT)

Flexibility in Design is an effective way to manage uncertainty. It enables system managers to adapt to evolving environments, to avoid bad situations and take advantage of emerging good opportunities.
The approach is strategic. It views systems management as a dynamic process in which designers necessarily add or change capacities and capabilities over time. As in chess, the key to success lies in positioning the system to provide valuable options. Flexibility in design is most desirable when the future is most uncertain, exactly when options are most valuable.
Flexibility in Design contrasts with Robust design. Rather than minimize the variation of future system performance, Flexibility in Design redistributes the variation in performance, reducing the downside possibilities while maximizing upside potential.
The presentation outlines the process of achieving Flexible Designs, and demonstrates its operation and value through examples. The analysis maximizes overall expected system value. It starts with explicit recognition of underlying uncertainties – in sharp contrast to conventional systems design based on fixed system requirements. The process explores the distribution of possible outcomes associated with alternative design concepts, generally by Monte Carlo simulations.
Example applications indicate that Flexibility in Design routinely leads to 10 to 30% increases in expected value. The intuition is that it guards against the highest risks (a win), enables taking advantage of new opportunities (more win), while frequently reducing immediate capital costs (by deferring decisions on capacity and function). The net effect in general is: more wins at lower cost!

Bio: Dr. Richard de Neufville is Professor of Engineering Systems and of Civil and Environmental Engineering at MIT. He specializes in Systems Analysis and Design of major infrastructure. His work now focuses on flexibility in technological systems. This is logically equivalent to using “real options”, but in engineering the analysis differs substantially from that of financial options. This approach implies a fundamental shift in engineering design, from a focus on fixed specifications, to a concern with system performance under the range of possible risks and opportunities. He has worked widely – geographically and substantively -- on many projects, including hydropower, oil platforms, copper mines, and his substantive specialty, airports. He is author of Flexibility in Engineering Design (MIT Press, 2011), Airport Systems Planning, Design and Management, (McGraw-Hill, 2nd edition, 2013); Applied Systems Analysis (McGraw-Hill) and other texts. Numerous prizes have recognized his work, including the Sizer Award for the Most Significant Contribution to MIT Education for having founded and led the MIT Technology and Policy Program. He has an MIT PhD and a Delft Dr.Hc. Born in the United States, he enjoyed 7 years of school in Switzerland. Prof. de Neufville is a CRAG (EPFL Center on Risk Analysis and Governance) visiting professor at the Laboratory of Hydraulic Construction.

Organized by Prof. Nikolas Geroliminis & Prof. K. Beyer
14/03/2014 @ 12:15 room GC B330

Potentials for Collaborations and Recent Advances On the value of Information in Structural Health Monitoring

Prof. Michael H. Faber (DTU)

EPFL and DTU are both members of the Eurotech University Alliance together with Technische Universiteit Eindhoven and Techische Universität München. One of the aims of this partnership concerns research collaborations within the European dimension, hereunder the HORIZON 2020 program. With the purpose of enhancing the research collaborations between the Civil Engineering Departments of EPFL and DTU the first part of the presentation thus aims to provide an overview of some of the main research interests and activities of DTU Civil Engineering.
Structural Health Monitoring (SHM) has, over the last 2-3 decades, become a topic of significant interest within the structural engineering research community, but also in the broader areas of civil and mechanical engineering. Whereas the merits of health monitoring are generally appreciated in qualitative terms there has, as of yet, not been reported much fundamental research on the quantification of the benefit of SHM. The present presentation, addresses the quantification of the value of SHM taking basis in the Bayesian pre-posterior decision analysis and the concept of Value of Information (VoI) analysis.

Starting point is taken in the identification of different typical situations in structural engineering in which health monitoring would have the potential to provide value beyond its costs. Subsequently, the theoretical framework which allows for the quantification of its value is shortly summarized and illustrated on a principal example. Subsequently, the use of the VoI concept in optimization of inspection and maintenance strategies of fatigue sensitive details in welded connections of offshore structures is illustrated and finally a potential framework for future collaborations within the EU COST Action program is outlined.

Bio: Michael Havbro Faber is professor in Risk and Safety and the head of the department of civil engineering at the Technical University of Denmark, DTU.
His research is directed on engineering decision making with focus on applied Bayesian decision theory, life safety, management of catastrophic risks, risk assessment, Bayesian uncertainty modeling, structural reliability and risk based assessment and maintenance. During his career Michael H. Faber has engaged continuously in industrial projects and acts as a consultant in ongoing projects related to offshore safety and reliability, transport risk and life safety assessments as well as natural hazards risks management.
Michael H. Faber is a member of the Danish Academy of Technical Sciences and is actively involved in several international committees, including: The Joint Committee on Structural Safety (vice-president); the International Forum on Engineering Decision Making (founding president); the Civil Engineering Risk and Reliability Association (chair) and alumni of the WEF GAC on Catastrophic Risks.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
21/03/2014 @ 12:15 room GC B330

Efficient algorithms for DNL and DTA as lower level component in bi-level optimization

Prof. Chris M.J. Tampère (KU Leuven, Belgium)

Many analyses require a large number of DNL/DTA runs as the lower level in a bi-level optimization: e.g. optimizing network-wide traffic control, dynamic tolling, network design and dynamic origin-destination (OD) estimation.
Repeated lower level calculations get substantially more efficient by exploiting the considerable overlap between successive iterations, which usually differ only marginally from a base scenario (e.g. gradient approximation) or move progressively (with relatively small steps) in some large solution space. This is exploited in Marginal Computation (MaC) algorithms for the Link Transmission Model, a first order macroscopic network simulation model. It starts from a known DNL/DTA solution, and changes marginally those state variables that differ between the previous iterate and the current.
The seminar presents LTM and two MaC versions of it. One uses a traditional, CFL-consistent calculation scheme. It progresses forward in time, guaranteeing consistency of traffic propagation immediately at each new time step. It is about 40 times faster on mid-sized networks than a full LTM run. But it is quite complex and approximation errors increase as one moves further from the base scenario. i-LTM was re-engineered to account from scratch for marginal computation. It iterates to a fixed-point between a forward propagation stage and a backward stage imposing propagation constraints. They flag to each other which variables have changed compared to a previous iteration, herewith limiting recomputation parsimoniously to only those space-time grid points. Not only does this procedure by-pass CFL requirement on the time step size, it elegantly computes variations to a previous DNL/DTA as flagged changes that are iterated parsimoniously to a new fixed-point.
The seminar presents an application of dynamic OD calibration, where MaC allows for numerical jacobian approximation of DNL/DTA in reasonable time. Exploiting this sensitivity information increases substantially the quality of the optimization on the upper level.

Bio : Chris M. J. Tampère (°1973, Antwerp, Belgium) holds a Masters’ degree in Civil Engineering (1997, KU Leuven, Belgium) and a PhD from Delft University of Technology (2004, The Netherlands).
At TNO Inro, Delft (1997-2003) he developed the MIXIC microsimulator for traffic flows with a variety of Advanced Driver Assistance systems and several travel time estimation and prediction algorithms for freeway and urban networks. His PhD research with TU Delft and TRAIL was on traffic flow theory for ADA systems in congested flows (2004). As a Postdoc Researcher at KU Leuven, he developed realtime models for estimation and prediction of urban traffic conditions (IWT postdoc grant), and did research on network structures, travel time reliability, network traffic management, Dynamic Network Loading (DNL) and Dynamic Traffic Assignment (DTA) models.
Since 2010, he is a Tenure Track Professor at the CIB – Traffic & Infrastructure unit at KU Leuven. He was co-founder of the master in engineering on traffic, logistics and ITS (VLITS), in which he teaches courses on Transportation Engineering, Transport Modeling, Intelligent Transportation Systems, and Dynamic Traffic Management. His current research continues with DNL/DTA modeling and calibration, integrated infrastructure, demand and traffic management in regional transportation networks (KUL research fund), and network design problems with multiple transportation service suppliers.

Organized by Nikolas Geroliminis & Katrin Beyer
27/03/2014 @ 13:30 room ELG120

Two applications of sparse and low-rank signal modelling

Dr. Pavel Rajmic, SPLAB, Brno University of Technology, Czech Republic
Bio: Pavel Rajmic has been employed as researcher at the Faculty of Electrical Engineering and Communication, Brno University of Technology since 2004. He is a member of the team SPLab dealing with digital multimedia signals processing at the Department of Telecommunications. In 2001, he worked as a statistician in analyzing large-scale data coming from the longitudinal psychological research project ELSPAC at the Institute for Research on Children, Youth and Family by the Faculty of Social Studies MUNI Brno.

In this talk, I will present two topics recently addressed by my students. The first problem falls into audio processing and the second one to image/video processing.

Audio recordings are sometimes affected by defects or even loss of information caused either by obsolete carriers (LP, magnetic tapes) or signal transmission drop-outs. The problem referred to as "audio inpainting" aims at recovering the information in such signal segments. Historically, these problems were solved by interpolation approaches based mostly on autoregressive modelling of partial harmonics. Since most natural signals are sparse with respect to some time-frequency transform, sparse signal priors were utilized in developing related optimization programs. We will compare the old methods with the sparsity-based approach and discuss promising new results based on structured sparsity.

Perfusion MRI is a diagnostic method in medicine used mainly for diagnosing carcinoma and cardiovascular diseases. Herein, a contrast agent is injected in the patient and its concentration then tracked via MRI during time. The signal captured this way from the affected area can be approximated by the lognormal distribution curve. The standard way of obtaining the MR measurements is very slow and does not comply with today’s challenging requirements. We propose using compressed sensing to acquire much less coefficients, having minimal effect on the signal reconstruction. The approach is based on the assumption that the data can be well approxiamted as a sum of low-rank matrix and a matrix sparse in row spectrum.

Organized by Benjamin Ricaud
LTS2 EPFL
28/03/2014 @ 12:15 room GC C330

Understanding energy foundations

Prof. Peter Bourne-Webb (IST)

In the paper “A framework for understanding energy pile behaviour”, the authors outlined a simple schematic description of the expected response of a pile to heating and cooling which was used to understand the results of field tests on thermally-activated piles that had been carried out in London and in Lausanne.
This presentation provides some context for the energy foundation concept in terms of how it fits into the technology of shallow geothermal heating and cooling, discusses heating & cooling, and thermo-mechanical performance of energy piles that has been observed, and then outlines the framework proposed in the paper. Finally, the preliminary results of more recent studies undertaken to explore the limits applicability of the framework, in particular its inability to capture the impact of other thermal interactions that also affect the changes in pile axial load and mobilized shaft resistance generated by thermal loading of the pile – i.e. the soil coefficient of thermal expansion and the temperature field around the pile.

Bio: Peter Bourne-Webb is assistant professor at the Instituto Superior Técnico in Lisbon, Portugal. Having spent his formative years in New Zealand, graduating from the University of Canterbury and working initially for Works Consultancy Services (the former Ministry of Works), Peter moved to the UK where he completed his MSc and PhD at Imperial College completing theses under the supervision of Professor David Potts. Whilst living in the UK, he also worked for the Geotechnical Consulting Group, Card Geotechnics and latterly, Cementation Skanska where he began his involvement with the energy foundation concept. In Portugal he is continuing to research energy foundations. He recently contributed two chapters to the book “Energy Geostructures” edited by Prof. Laloui and Alice Di Donna – one on the observed response of energy geostructures and one on the planning/design, delivery & commissioning of energy geostructures.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
04/04/2014 @ 12:15 room GC C330

Macroscopic models of traffic flow

Dr. Paola Goatin, INRIA, Sophia Antipolis, France

Macroscopic traffic flow models derived from fluid dynamics are very popular nowadays both for vehicular and pedestrian flows.
They offer a sound mathematical basis relying on well posedness results for hyperbolic non-linear conservation laws,
as well as fast and efficient numerical tools consisting of finite volume schemes.
I will present some recent results concerning models with phase transitions, flux constraints and non-local velocities, that can be used to describe some particular characteristics of traffic flow. In particular, I will show how phase transitions models allow for a better matching with experimental data, and are able to describe forward moving discontinuities in the congested phase. Conservation laws with flux constraints have been introduced to efficiently model toll-gates, constructions sites and also moving bottlenecks created by slow-moving large vehicles. Finally, models consisting of conservation laws with non-local flux have recently being introduced to capture the reaction of drivers to the downstream traffic.This approach could address the bounded acceleration issue of classical macroscopic models (which account for unrealistic infinite acceleration across shock discontinuities).

Bio: Paola Goatin holds a PhD in Functional Analysis from the International School for Advanced Studies in Trieste (Italy),
and a Habilitation (HDR) in Mathematics from Toulon University (France).
She has been assistant professor at Toulon University, before joining INRIA as a research scientist in 2010.
Her research activity focuses mainly on the analysis and numerical approximation of systems of partial differential equations of hyperbolic type.
Targeted applications include traffic flow modeling and management.
In particular, she currently holds an ERC Starting Grant for the project "Traffic Management by Macroscopic Models - TRAM3".

Organized by Nikolas Geroliminis & Katrin Beyer
02/05/2014 @ 12:15 room GC C330

Seismic design and assessment of bridges using advanced inelastic analysis tools

Prof. Andreas Kappos (City University, UK)

Modern codes for seismic design of buildings, bridges, and other civil engineering structures offer to the designer the choice between elastic and inelastic analysis methods, i.e.
• ‘Traditional’ methods wherein design is based on the results of a series of elastic analyses that provide linear action effects that are reduced by a global force reduction factor (q-factor in Europe, R-factor in the US) that depends on the overall ductility and overstrength capacity of the structure.
• Displacement and/or deformation based methods, wherein inelastic deformation demands in the structure are estimated for a given level of the seismic action with the aid of a series of inelastic analyses of either the static or dynamic type. These demands are then checked against the corresponding deformation capacities of the critical structural elements.
Over the last two decades, researchers and engineers have gradually shifted towards the performance-based assessment and design concept, wherein inelastic deformation demands are (preferably) directly obtained from the aforementioned nonlinear response analysis of the structure. The safety verification then involves comparing these demands against the deformation capacities to verify the performance of the structure with respect to a given performance objective (e.g. allowable member rotation for ensuring life safety under a ground motion having an appropriately selected probability of occurrence). This type of analysis is more suitable for the assessment of existing structures (where member strengths can be calculated before carrying out the analysis) than for the design of new ones.
The lecture will focus on the use of inelastic analysis methods for the seismic assessment and design of bridges, for which the work carried out so far, albeit interesting and useful, is nevertheless clearly less than that for buildings. A critical overview of nonlinear static (pushover) methods that account for higher mode effects (which are typically significant in bridges) will be given, along with comparisons with response-history analysis results.
In addition to analysis methods, the lecture will include a presentation of a deformation-based design method that can be applied to bridges with several significant modes.

Bio: Prior to joining City University (in March 2013) Andreas Kappos was a Professor at Department of Civil Engineering, of the Aristotle Univ. of Thessaloniki since 2002, and Head of the Structures Section from 2008 to 2010. He has first joined the Department as a lecturer in 1988, after having completed his PhD studies in 1986. In 1983-1984 he was a Visiting Research Fellow at the Univ. of California, Berkeley. From 1995 to 1999 he worked at the Dept. of Civil Engineering, Imperial College London (UK), first as a lecturer and later as a Reader of Earthquake Structural Engineering.
Andreas Kappos is the Secretary of the European Association of Earthquake Engineering (EAEE) since 2010 and the Coordinator of the EAEE Working Group on Bridges since 2004. He has also served as a member of a number of scientific committees dealing with seismic design (incl. the Eurocode 8 Project Team) and assessment (various fib and EAEE task groups).

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
09/05/2014 @ 12:15 room GC C330

Initiation and crack growth with the Thick Level Set damage model coupled to the eXtended Finite Element Method

Prof. Nicolas Moës (Ecole Centrale de Nantes)

Crack initiation relies mainly on damage mechanics whereas crack propagation relies on fracture mechanics involving displacement discontinuity across a propagating crack. We propose a new model bridging these two mechanisms. Damage is expressed in terms of an evolving level set. In the wake of the front (iso-zero of the level set) damage is directly related to the distance of the front with a function considered as a material data. The new model is coined Thick Level Set because not only the location of the iso-zero is useful but all values up to the critical distance (lc) beyond which the material is considered fully damaged (d=1). In the TLS model, the crack location is defined as the set of points located further than the critical distance to the front. The crack placement in the damage band is thus part of the model.
From a numerical point of view, once a crack appears in the simulation (appearance of an iso-lc), it is taken into account with the eXtended Finite Element Method: displacement are allowed to be discontinuous across the iso-lc through the use of an Heaviside enrichment (or several Heaviside enrichments in the case where the support is cut into several pieces). Because of this enrichment, the mesh may be coarsen away from the evolving damage zones.
Several numerical experiments in 2D and 3D quasi-static and dynamic simulations of quasi-brittle failure will demonstrate the capabilities of the TLS regarding initiation, branching and propagation of cracks over long distances.

Bio: Dr. Nicolas Moës is professor of mechanical engineering at Ecole Centrale de Nantes, France, since 2001. He obtained his Ph.D. from the Ecole Normale Supérieure de Cachan and then spent several years at University of Texas Austin and Northwestern University where he was appointed as research assistant professor. Prof. Moës is a fellow member of the International Association for Computational Mechanics and the recipient of several awards including the Silver Medal from the CNRS in 2014 and an ERC advanced grant in 2012.

Organized by Prof. Nikolas Geroliminis & Prof. Katrin Beyer
23/05/2014 @ 12:15 room GC C330

The CEOS.fr research project Behaviour and assessment of massive structures: cracking and shrinkage

Prof. Philippe Bisch, Ecole des Ponts ParisTech (ENCP), France

The majority of concrete structures have to fulfil a number of structural functions beyond that of simple resistance. These include behavioural requirements for: reinforced concrete cracking, deformability, water and air leak-tightness, sustainability.

Most European concrete structures today are designed in accordance with Eurocode 2, which uses a performance-based approach related to durability and functionality at Serviceability Limit State.
For massive structures, the standard rules do not fully reflect the complete behaviour of massive elements, for which thermo-hydro-mechanical effects, scale effects and structural effects influence cracks spacing and width. This may lead to structures which are not optimised, especially for reinforcement.
To address these concerns, the French civil engineering community decided in 2008 to launch a joint national research project, CEOS.fr, with the aim of making a significant step forward in the engineering capabilities for predicting the expected crack pattern of massive structures under anticipated in-service or extreme conditions.

The aims of the CEOS.fr project are to:
• develop numerical nonlinear and damage models, to simulate concrete behaviour under load and deformation;
• provide engineering guidelines to optimise the design of massive concrete structures;
• propose further rules for crack width and crack spacing assessment in massive concrete structures, in addition to EC2 or fib Model Code 2010.
The lecture will give general information regarding the experimental and numerical aspects of the research project, but a particular emphasis will be given to shear walls and of the conclusions which have been drawn for the assessment of skew cracking.

Bio : PHILIPPE BISCH is professor at the Ecole des Ponts ParisTech (ENPC) and has been in charge of several courses in the field of Mechanics of Structures. In parallel, he is also director at EGIS Industries, a major engineering firm.
He has been President of the French Association of Earthquake Engineering (AFPS) and of the European Association (EAEE). He has been participating for a long time in French and European standards, mainly for aseismic design, and is one of the authors of Eurocode 8.
He is presently the technical director of the research project CEOS.fr which will be presented during the seminar.

Organized by Nikolas Geroliminis & Katrin Beyer
20/08/2014 @ 09:45 room BC 420

4th Annual Meeting of National Competence Center for Biomedical Imaging

A wide-ranging list of experts in the domain
Speakers: Prof. Gruetter, EPFL, NCCBI Spokesperson
Dr. Dominique Zosso, NCCBI Alumni, CAM Assistant Adjunct Professor, UCLA, USA
Philipp R. Spycher, ETHZ
Aline Seuwen, ETHZ
Arboleda Clavijo Carolina, PSI & ETHZ
Thomas Kirchner, ETHZ
Auffret Matthieu, EPFL
Paul Guichard, EPFL
Diego G. DUPOUY, EPFL
Sarah Sonnay, EPFL
Michel Akselrod, ETHZ (poster only)
Prof. Sebastian Kozerke on behalf of Christian Binter, ETHZ
Scott Lindner, EPFL
Arun Shivanandan, EPFL
Flippo Arcadu, on behalf of Goran lovric, PSI & ETHZ
Thanuja Ambegoda, ETHZ
Mohan Obbineni Jagan, PSI
Philippe Diderich, EPFL

The National Competence Center for Biomedical Imaging (NCCBI) is an initiative in biomedical imaging launched by the ETH domain.

Its mission is to advance imaging technology in Switzerland beyond institution-specific investments and activities. The NCCBI serves to develop synergies among the academic institutions involved and to coordinate imaging investments within the ETH domain dedicated to advance the development of biomedical imaging in Switzerland above and beyond institution-specific investments and activities.

Organized by NCCBI - National Competence Center for Biomedical Imaging| EPFL SB IPSB LIFMET|Station 6| 1015 Lausanne| Switzerland| www.nccbi.ch
26/09/2014 @ 12:15 room GC C330

A Dynamic Environmentally-friendly Planning and Operation Platform (DEPOT) for Chinese Medium-size Cities

Prof Dr Meng Li, University of Tsinghua, China

In recent years, China has been in the high-speed urbanization process. Under the rapid growth of economy, car ownership and drivers, together with massive population movement toward urban areas, the traffic congestions and safety are steadily worsening, not only in major cites but also in the medium-size cities. A national ITS R&D project started with the analysis of the unique traffic characteristics of such Chinese medium-size cities. Three common characteristics are: 1) sharp increase in traffic demands; 2) significant tidal phenomena during peak times on the major corridors; 3) land-use and demand pattern can vary significantly during the development period.
In this study, a dynamic environmentally-friendly planning and operation platform (DEPOT) is being developed to evaluate and optimize comprehensive strategies, e.g. traffic management, policy and planning strategies. The simulation-based optimization approach is applied on DEPOT. Some research modules under this project are: 1) the agent-based behavior model for mode shift; 2) the redistribution operation model for bicycle-sharing system; 3) the cooperated VMS guidance and signal control system; and 4) the coordination of dynamic parking pricing and transit service.

Bio : Dr. Meng Li is an Associate Professor in the Department of Civil Engineering at Tsinghua University, and Deputy Director, Tsinghua – Daimler Center for Sustainable Transportation. His main research areas are transportation system analysis and modeling, intelligent transportation systems, travel behavior analysis and data mining. As the principle researcher, Dr. Li has been undertaking the National High Technology Research and Development Program of China, National Natural Science Foundation of China key project, and the World Bank and the global environment facility (GEF) supported research and development projects. Dr. Li is a scientific committee member of World Conference on Transport Research Society (WCTRS), a member of traffic signal system committee (AHB25) of Transportation Research Board, a member of Intelligent Transportation Signal Operation (ITSO) Committee of Institute of Transportation Engineering (ITE) and a member of American Society of Civil Engineering (ASCE). Prior to his current appointment at Tsinghua University, he worked as an R&D engineer at University of California at Berkeley between 2004 and 2010. Dr. Li received his National Science & Technology Progress Award Grade 2 in 2011.

Organized by Prof. Nikolas Geroliminis & Katrin Beyer
03/10/2014 @ 12:15 room GC C330

Postdoctoral Funding Opportunities and Grant Preparation

Dr Geraldine Canny, program manager, EPFL research affairs

The Civil and Environmental Engineering PhD students’ representatives are pleased to announce the following seminar to answer your questions:

• Do you know which funding opportunities are available for postdoctoral positions around the world?
• Would you like to find out about the deadlines of these opportunities and the timelines?
• Have you thought about the documents you will need and the criteria on which your application will be evaluated?

Organized by Mohadeseh Taheri Mousavi and Parag Rastogi
17/10/2014 @ 12:15 room GC C330

Development of New Methods for Cross-Section Resistance and Member Stability Checks - Research Methods, Design Rule Development and Validation

Prof. Andreas Taras, University of Graz, Austria

In this talk, a number of current and new proposals for the design of steel cross-sections and members against local and global instability will be discussed. The focus will be put on the scientific methodology used for their development: on the analytical background, on the employed experimental and numerical methods and their results, on the concepts behind the formulation of the design rules for stability, and their probabilistic validation.

Bio : Andreas Taras is assistant professor for steel structure at the University of Graz, Austria. He obtained his Master and PhD degree from the same university in 2009. His main research interests comprise stability and ductility of steel structures, behaviour of tank, silo and pipeline structures, and fatigue and fracture in steel structures

Organized by Prof. Nikolas Geroliminis & Katrin Beyer
24/10/2014 @ 12:15 room GC A331

Pressure and stress fluctuations in fracturing saturated porous media

Prof. Bernhard Schrefler, University of Padua, Italy

With E. Milanese, P. Rizzato, J.M.R. Huyghe, J.F. Molinari, S. Secchi, L. Simoni

The pressure and stress evolution in fracturing saturated porous media is investigated on meso-mechanics and macro-mechanics level. Crack propagation under external loading (peel test and biaxial loading), assigned pressure and assigned flux (fracking) is considered. For meso-mechanics investigations a lattice model is used which has been introduced in a Biot-type formulation. The avalanche behaviour of the cracking events is evidenced.

At macro mechanics level both standard Finite Elements with remeshing and appropriate crack-tip advancement algorithm, and XFEM are used. A cohesive fracture model is adopted together with a discrete crack approach and without predetermined fracture path. The Rankine criterion is used for fracture nucleation and advancement. In the standard FE approach the fracture follows in a 2D setting directly the direction normal to the maximum principal stress while in the 3D case the fracture follows the face of the element around the fracture tip closest to the normal direction of the maximum principal stress at the tip. This procedure requires continuous updating of the mesh around the crack tip to take into account the evolving geometry. The updated mesh is obtained by means of an efficient mesh generator based on Delaunay tessellation [1, 2, 3]. Comparison is made with the XFEM method. The governing equations for all approaches are written in the framework of porous media mechanics and are solved numerically in a fully coupled manner. Numerical examples include well injection (constant inflow) in a geological setting, hydraulic fracture in 2D and 3D concrete dams (increasing pressure) and a peeling test for a fully saturated porous medium; stepwise tip advancement and pressure oscillations are shown. A comparison with results found in literature and with the solutions obtained with the XFEM method evidences the shortcomings of methods like PUFEM, XFEM and Phase Field methods when used in their traditional way for the simulation of the coupled phenomena going on at the crack tip.

Bio: Bernhard A. Schrefler holds a ME degree from the University of Padua and a PhD and DSc from the Swansea University, Wales. He is Secretary General of the International Centre for Mechanical Sciences in Udine, Professor Emeritus of the University of Padua and Senior Affiliate Member of the Houston Methodist Research Institute, TX. For his research work Dr. Schrefler has been awarded the Maurice A. Biot Medal from ASCE, the Euler Medal from ECOMAS, the Computational Mechanics Award from IACM, the IACM Award and the Palmes Académiques in France. He has received honorary doctorates from the St. Petersburg State Technical University, the University of Technology of Lodz, the Leibniz University of Hannover, the Russian Academy of Sciences and the Ecole Normale Supérieure at Cachan, an honorary fellowship from the University of Wales Swansea and an honorary professorship from the Dalian University of Technology. Dr. Schrefler is member of the National (Italian) Academy of Sciences, of the Accademia Galileiana di Scienze, Lettere ed Arti and of the Istituto Veneto di Scienze, Lettere ed Arti.

Organized by Prof. Nikilas Geroliminis & Katrin Beyer
28/10/2014 @ 09:00 room Forum Rolex Learning Center

Open Research Data: The Future of Science

Some of the main specialists in the research data field will participate in this event. European Commission, Swiss National Science Foundation, PLOS, CERN, ETH Zürich and the EPFL Audiovisual Communications Laboratory will be invited speakers for the plenary conferences. Philippe Gillet, EPFL Vice-president for Academic Affairs, will give the opening speech.

•   Importance of collecting research data
•   Open research data evolutions, challenges and stakes
•   Implementation of open research data policies in universities
•   Best practices: insights and applications
•   Technical aspects, software and tools
•   Idea-sharing on the future of open data in science

In the afternoon, workshops and specific presentations on different topics and software (duration: 1hr) will allow participants to share experiences and to foster interactive discussions. The main speakers will be staff members of ETH Zürich, ORCID, Zenodo and the new EPFL LIMS service.

≫ Registration form for the event. If you do not pre-register, we will not be able to send you the registration form for presentations and workshops, which is not available online. Please remember that the registration form for workshops and presentations is due by Monday, October 20.

List not yet complete. More talks and workshops will be announced soon.
Registration Form
Webpage

Organized by EPFL Library
28/10/2014 @ 14:00 room EPFL Innovation Park Neptune Meeting Room

TSMC Technology Seminar

TSMC Europe
Bio: Mrs. Maria Marced is President of TSMC Europe, with responsibility for driving the development, strategy and management of TSMC’s business in Europe. Before joining TSMC, Maria was Senior Vice President and General Manager of Sales and Marketing at NXP Semiconductors/Philips Semiconductors. Maria joined Philips Semiconductor in September 2003 as Senior Vice President and General Manager of the Connected Multimedia Solutions Business Unit overseeing Philips' semiconductor solutions for Connected Consumer applications. Previous to her work with Philips, Maria was employed at Intel where she developed her professional career for more than 19 years, reaching the top position in the Europe, Middle East and Africa region as Vice President and General Manager. Mrs. Marced studied Telecommunications Engineering at Universidad Politecnica de Madrid, Spain. She was born in Valencia-Spain and she is married with one daughter.

TSMC created the semiconductor Dedicated IC Foundry business model when it was founded in 1987. TSMC served about 440 customers and manufactured more than 8,600 products for various applications covering a variety of computer, communications and consumer electronics market segments. TSMC is headquartered in the Hsinchu Science Park, Taiwan, and has account management and engineering service offices in China, Europe, India, Japan, North America, and, South Korea. The talk will highlight advanced and "More-than-Moore" wafer production processes, nanoscaled technologies as well as unique R&D integration of cutting-edge process technologies, pioneering design services, manufacturing productivity and product quality.

Organized by Professor Giovanni De Micheli, IEL Director
31/10/2014 @ 12:15 room GC C330

Stochastic Approximations for the Macroscopic Fundamental Diagram of Urban Networks

Prof. Dr Jorge Laval, Gerogia Tech, Atlanta, USA

This presentation focuses on a theory for estimating the Macroscopic Fundamental Diagram (MFD) on inhomogeneous corridors and networks using probabilistic methods. By exploiting a symmetry property of the stochastic MFD, whereby it exhibits identical probability distributions in free-ﬂow and congestion, it is found that the network MFD depends mainly on two dimensionless parameters: the mean block length to green ratio and the mean red to green ratio. The theory is validated with an exact trafﬁc simulation and with the empirical data from the city of Yokohama. It is also shown that the effect of buses can be approximated with the proposed theory by accounting for their effect in the red to green ratio parameter.

Bio : Jorge Laval is an Associate Professor at the School of Civil and Environmental Engineering, which he joined in 2006. After obtaining his B.S. in Civil and Industrial Engineering from Universidad Catolica de Chile in 1995, Dr. Laval worked as a transportation engineer for 5 years at the Chilean Ministry of Public Works in Santiago, Chile. He received his Ph.D. in Civil Engineering from the University of California, Berkeley in 2004. Prior to joining Georgia Tech, Dr. Laval held two consecutive one-year postdoctoral positions at the Institute of Transportation Studies at UC Berkeley, and at the French National Institute for Safety and Transportation Research (INRETS). Professor Laval's main research thrust is in the area of traffic flow theory, modeling and simulation, focusing in understanding congestion in urban networks and how to manage it. He has made important contributions towards understanding the capacity of freeways, the connection between driver behavior and stop-and-go waves, freeway ramp-metering strategies, dynamic traffic assignment and congestion pricing.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
07/11/2014 @ 12:15 room GC C330

Damage hybrid and meso-modelling of composite: the framework and some complement to deal with impact and energy absoption

Prof. Olivier Allix, ENS Cachan, France

The intensive use of long-fibers composite laminates in aeronautics or automotive applications implies to master the prediction of any behaviour up to final failure. The so-called virtual testing approach supports this goal and relies on the use of robust models for key physical mechanisms.
Following the works of Ladevèze [1-2] and co-workers this presentation will rely on two types of models to deal with:
- hybrid model for material virtual testing of small coupons, where all possible cracks are introduced ;
- an homogenized damage meso-model for the virtual testing of larger specimens.

Motivated by the virtual testing of energy absorbers the presentation will discussed, within those model frameworks, the introduction of two particular aspects: the kinking phenomenon [3] and the rate dependent modelling of delamination [4]. The question of the objective simulation of erosion and failure of composite in dynamics by damage mechanics will also be discussed [5].

[1] P. LADEVEZE, G. LUBINEAU, AND D. VIOLEAU. A computational damage micromodel of laminated composites. International Journal of Fracture, 137(1):139-150, 2006.
[2] LADEVEZE, P., LUBINEAU, G., MARSAL, D. Micromechanics and Mesomechanics of Laminates: Synergy and Model Improvements. Jounal of the Mechanical Behavior of Materials. Vol 19. Num 2-3. Pages 159-166. 2009
[3] ALLIX O., FELD N. , BARANGER E., GUIMARD J-M & HA-MINH C., The compressive behaviour of composites including fiber kinking: modelling across the scales, to appear in Meccanica 2014
[4] GUIMARD, J.M., ALLIX, O., PECHNIK, N., THEVENET, P. Characterization and modeling of rate effects in the dynamic propagation of Mode-II delamination in composite laminates. Int Jal of Fracture. Vol 160. Num 1. Pages 55-71. 2009
[5] ALLIX, O. The bounded rate concept: a framework to deal with objective failure predictions in dynamic within a local constitutive model. Int Jal of Damage Mechanics. Vol 22. Pages 808-828. 2013

Bio : Olivier Allix is Professor (of Exceptional class) at the Ecole Normale Supérieure de Cachan and previous director of LMT-Cachan and is member of the prestigious Institut Universitaire de France. Olivier Allix has worked intensively in connection with Airbus and other companies on the modelling of the mechanical behaviour of composites and the developement of multiscale strategies to deal with those complex material and structures. He recently proposed non intrusive computational methods to easily implemnt those techniques into commercial packages. Olivier Allix serves as member of 12 editorial boards of international journals. He organized the Fourth European Conference on Computational Mechanics in Paris in 2010 with more than 2000 participants and is an Euromech and IACM fellow.

Organized by Prof. Nikolas Geroliminis & Katrin Beyer
12/11/2014 @ 12:15 room GC A3 30

Les dégradations du béton vues sous l’angle du matériau et de la structure

Prof. David Conciatori, Université Laval, Québec

Le département de génie civil et génie des eaux à l’Université Laval possède un grand laboratoire mécanique et environnemental. Ses nombreuses chambres climatiques, sa chambre saline, ses presses, etc. lui permettent de placer des éléments structuraux dans un environnement contrôlé en température et en humidité, et, par exemple pour reproduire des conditions hivernales réelles. Dans ce contexte et cet environnement, cette présentation sera divisée en 3 parties; (1) présentation générale rapide de l’Université Laval et du département de génie civil et génie des eaux, (2) experts, expertises et laboratoire et (3) développement d’outils de prédiction de l’évolution de la sécurité structurale d’un ouvrage en béton. Un résumé de la partie (3) est développé ci‐dessous.

Les détériorations rapides par la corrosion des ouvrages d’art nécessitent des investissements considérables des gouvernements. Un grand nombre de chercheurs s’intéresse à cette problématique. Les détériorations les plus rapides observées sur les ouvrages d’art se développent en présence simultanée d’eau liquide et de chlore qui accélèrent le processus de migration du chlore à l’intérieur du béton d’enrobage. Les ouvrages d’art dans les pays nordiques et/ou en zone côtière sont les plus touchés; le Canada fait partie de ces pays. Les détériorations par corrosion peuvent également apparaître à plus long terme en cas d’exposition à un brouillard salin et/ou avec un processus de carbonatation du béton. Il existe beaucoup de modèles de prédiction de transport, comme Stadium, Ms Diff, Masi, Shin, Schmidt‐Döhl, TransChlor (TC), ClincConc, Meijers, Saetta et Ishida. Tous les modèles prennent en considération des conditions d’exposition climatiques et environnementales simplifiées et la plupart ne prennent pas en considération l’effet de capillarité dû à la présence de l’eau liquide. Notons que le modèle "TC", développé à l’EPFL, prend en considération ces composantes. Lorsque des aspects non déterministes sont étudiés, les modèles utilisés sont encore plus simplifiés, afin que des méthodes de Monte‐Carlo puissent être utilisées. Il a été démontré que ces modèles simplifiés sont applicables seulement pour des cas idéaux et peuvent conduire à des résultats erronés dans les applications réelles. Aujourd’hui, des méthodes probabilistes simples permettent de prendre en considération la variabilité dans ces modèles de transport complexes, notamment avec TC.

Les détériorations peuvent être étudiées au niveau du matériau et également au niveau structural. Le comportement aux sollicitations mécaniques des structures endommagées en béton armé, en béton de fibres, en béton fibré à ultra‐hautes performances et en béton précontraint peut être combinées avec l’historique des détériorations présentes et futures des structures. EPM3D (Endommagement Progressif Multiaxial), un modèle qui simule le comportement du béton sous charge triaxiale, permet d’évaluer l’État Limite Ultime de l’ouvrage. EPM3D se concentre sur la modélisation du comportement en flexion, en cisaillement, en torsion et en compression (piles de pont et poutres précontraintes) et également sur la modélisation des bétons fibrés et des bétons avec armatures composites. La combinaison des modèles de détérioration et mécanique permettra de fournir des informations plus précises sur la durabilité des ouvrages face aux actions climatiques et environnementales. Ces modèles peuvent également prendre en considération les relevés provenant d’auscultation sur le site et diminuer la variabilité des résultats. La gestion du patrimoine construit bénéficiera ainsi de données plus précises et adaptives au vieillissement, au climat, aux épandages de sel et aux auscultations.

Bio : Après l'obtention d'un PhD à l'EPFL/MCS David Conciatori est Post-Doc aux Université de Laval et Mc-Gill au Canada (bourse FNSF). Entre 2009 et 2014 il était responsable du laboratoire numérique dans le groupe de Structure à l'Ecole Polytechnique de Montréal. Depuis juillet 2014 il est professeur adjoint à l'Université de Laval (Ingénierie des structures et matériaux, spécialité : durabilité et durée de vie des infrastructures en béton).

Organized by Prof. Eugen Brühwiler, Florence Grandjean
12/11/2014 @ 18:15 room Polydôme

Landolt Public Lecture - "Green Chemistry: From Need to Market"

Prof. Philip Jessop, Queen's University, Canada
Bio: Dr. Philip Jessop, is a Canada Research Chair of Green Chemistry at Queen’s University in Kingston, Canada. He also serves as the Technical Director of GreenCentre Canada. After his Ph.D. (British Columbia, 1991) and a postdoctoral appointment (Toronto), he did contract research in Japan with Nobel laureate R. Noyori. As a professor at the University of California-Davis (1996-2003) and then at Queen’s, he has studied green solvents and the chemistry of CO2. Recent distinctions include the Eni Award for New Frontiers for Hydrocarbons (2013), Fellowship in the Royal Society of Canada (2013), and the Canadian Green Chemistry & Engineering Award (2012). He helped create GreenCentre Canada, a centre of excellence for the commercialization of green chemistry technologies. Switchable Solutions Inc. and Forward Water Technologies Inc. are two spin-off companies based upon Dr. Jessop's switchable solvents.

The old way to prevent pollution was to capture pollutants before they left the factory, which is always a financial burden. The Green Chemistry approach — “Design the process so pollutants aren’t made” — can reduce environmental impact while making industries more economically competitive. Economic benefits occur because designing processes to reduce pollution requires minimizing wasted energy and materials. What’s the catch? The right chemistry and societal conditions are necessary to bring these green processes to market. This layman-level presentation will introduce the concept of green chemistry and then follow the path of one new technology from its origin through to the creation of a company.

Organized by Landolt Chair @EPFL
14/11/2014 @ 12:15 room GC C3 30

Load Sequence Effects in Structural Durability

Prof. Dr Michael Vormwald, Technische Universität Darmstadt, Allemagne

Assessment of variable amplitude fatigue lives requires the application of a damage accumulation rule. The linear damage accumulation rule is widely used. Due to the summation rule for the relative consumed fatigue life its basic property is that the sequence of occurrence of the various cycles does not influence the calculation results. It is well known that the linear damage accumulation rule has deficiencies. They are related to the fact that in the physical fatigue damage accumulation the sequence of the occurrence of individual cycles indeed plays an important role. The material and the structure, respectively, have the ability to store information on prior loading histories. The damage – when measured in physical quantities, e.g. crack lengths, rather than sums of relative consumed fatigue life – of an individual cycle may be larger or smaller in variable amplitude fatigue compared to the constant amplitude case. In an attempt to rationalize the physical basis of sequence effects a classification of physical phenomena was undertaken. Two main groups of information storage possibilities have been identified: material’s plastic deformation and irreversible material separation processes leading to a changing geometry of the structure.

Bio : In 1983, Professor Vormwald received a diploma of the Technische Universität of Darmstadt (TUD) in civil engineering. He earned his doctorate in 1988 at the TUD to the doctor of engineering with a thesis on crack initiation life prediction for variable amplitude loading. He then worked until 1993 as a test engineer and project manager at the Industrieanlagen-Betriebsgesellschaft, Ottobrunn, where he gained practical experience in the durability design of mechanical engineering structures. He continued his scientific career with appointments as a professor at the University of applied science Jena, the Bauhaus University Weimar and until today at the TUD. His research work is focused on all aspects of deformation and failure processes with a special attention on the fatigue strength. The developed methods of evaluating strength have the aim to increase the safety of technical equipment. They should be understood and applied by engineers. He published over 70 articles, wrote well over 100 technical reports on strength investigations and his the co-author of several books among which : Advanced methods of fatigue assessment, with Dieter Radaj.

Organized by Prof. Dr Alain Nussbaumer
14/11/2014 @ 12:15 room GC C3 30

Load Sequence Effects in Structural Durability

Prof. Dr Michael Vormwald, (TUD) Technische Universität Darmstadt, Allemagne

Assessment of variable amplitude fatigue lives requires the application of a damage accumulation rule. The linear damage accumulation rule is widely used. Due to the summation rule for the relative consumed fatigue life its basic property is that the sequence of occurrence of the various cycles does not influence the calculation results. It is well known that the linear damage accumulation rule has deficiencies. They are related to the fact that in the physical fatigue damage accumulation the sequence of the occurrence of individual cycles indeed plays an important role. The material and the structure, respectively, have the ability to store information on prior loading histories. The damage – when measured in physical quantities, e.g. crack lengths, rather than sums of relative consumed fatigue life – of an individual cycle may be larger or smaller in variable amplitude fatigue compared to the constant amplitude case. In an attempt to rationalize the physical basis of sequence effects a classification of physical phenomena was undertaken. Two main groups of information storage possibilities have been identified: material’s plastic deformation and irreversible material separation processes leading to a changing geometry of the structure.

Bio : In 1983, Professor Vormwald received a diploma of the Technische Universität of Darmstadt (TUD) in civil engineering. He earned his doctorate in 1988 at the TUD to the doctor of engineering with a thesis on crack initiation life prediction for variable amplitude loading. He then worked until 1993 as a test engineer and project manager at the Industrieanlagen-Betriebsgesellschaft, Ottobrunn, where he gained practical experience in the durability design of mechanical engineering structures. He continued his scientific career with appointments as a professor at the University of applied science Jena, the Bauhaus University Weimar and until today at the TUD. His research work is focused on all aspects of deformation and failure processes with a special attention on the fatigue strength. The developed methods of evaluating strength have the aim to increase the safety of technical equipment. They should be understood and applied by engineers. He published over 70 articles, wrote well over 100 technical reports on strength investigations and his the co-author of several books among which : Advanced methods of fatigue assessment, with Dieter Radaj.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
18/11/2014 @ 11:15 room BC 01

Error correcting graphs and long term memory

Vincent Gripon, Telecom Bretagne
Bio: I am an associate professor (litterally in the french system a "Permanent Researcher") with Télécom Bretagne, one of the top French grande école and part of institut mines-télécom.

My research interests currently include:

    Associative memories,
    Brain inspired algorithms,
    Data structures,
    Signal processing on graphs.

We start with three simplifying hypothesis on brain functioning:

a) brain memory is redundant,
b) brain can be seen as a recurrent neural network and
c) storage of pieces of information in the brain is located at the scale of populations of neurons.

Using principles of error correcting codes, we then propose a very simple model for information storage and retrieval thanks to cliques in neural graphs. We show how this model can be enriched to address complex problems and its connections to actual neuroanatomical knowledge.

Organized by Benjamin RICAUD
19/11/2014 @ 17:30 room Rolex Learning Center & EPFL Innovation Park

EPFL Entrepreneurship Days
To celebrate its 10th anniversary, the Vice Presidency for Innovation and Technology Transfer (VPIV) joins the Global Entrepreneurship Week and organizes its first edition of the EPFL Entrepreneurship Days (EPFLED)!
***
Aware of the challenges in the local entrepreneurial ecosystem and well beyond the campus, EPFLED’s main mission is to promote entrepreneurship; to inspire aspiring entrepreneurs to get involved in company creation, to provide the necessary tools to create innovative projects, to focus on facilitating dialogue between established and future entrepreneurs and to shed light on company activities at EPFL’s Innovation Park.

On the program:
- Dense and refreshing keynotes to immerse yourself in start-up culture,
- Surprising and inspiring stories about the failures encountered by entrepreneurs,
- A workshop to share experiences on various innovation locations both domestic and abroad,
- A full afternoon to engage with people behind highly dynamic and innovative start-ups and companies at EPFL’s Innovation Park
Inspire, densify, demystify
Organized by Vice Presidency for Innovation and Technology Transfer (VPIV)
21/11/2014 @ 12:15 room GC C330

Masonry made sexy again: High level research, professional practice and innovation

Prof. Paulo LOURENÇO, University of Minho, Portugal

The evolution of structural masonry is briefly reviewed in the presentation, from old thrust line behavior to modern global behavior using shear walls.
Modern societies understand built cultural heritage as a landmark of culture and diversity. Only during the last decades the idea that ancient buildings could be conserved and reused became appealing. Large investments have been concentrated in this field, leading to impressive developments in the areas of inspection, non-destructive testing, monitoring and structural analysis of historical constructions. These developments, and recent guidelines for reuse and conservation, allow for safer, economical and more adequate remedial measures. The presentation first addresses the issues of the methodology to adopt, of different cases studies and of present challenges.

Bio : Full professor in the Department of Civil Engineering (DEC), University of Minho, Guimarães, Portugal, and coordinator of the Group of Historical and Masonry Structures. Head of the Institute in Sustainability and Innovation in Structural Engineering, with current contracted funding of 7.5 Million Euro and 100 PhD students. He supervised 35 PhD theses and is author of more than 1000 publications, with an h-index of 24. He is experienced in the fields of NDT, advanced experimental and numerical techniques, innovative strengthening techniques and earthquake engineering. He has worked as a consultant on several projects, including more than fifty monuments in different countries and has been responsible for several R&D projects with the masonry industry.
For modern structural masonry, the use of unreinforced, confined and reinforced masonry is briefly addressed, discussing the influence of seismic hazard and presenting different solutions adopted in developed countries. Recent research on building systems for modern masonry structures is presented, together with conclusions on the performance of the system for in-plane lateral loading. Finally, the performance of masonry infills and recent shaking table tests in Portugal are also presented.

Organized by Prof. Nikolas Geroliminis & Katrin Beyer
28/11/2014 @ 12:15 room GC C330

A mixed random utility - random regret model linking the choice of decision rule to latent character traits

Prof. Stephane Hess, University of Leeds, UK

An increasing number of studies are concerned with the use of alternatives to random utility maximisation as a decision rule in choice models, with a particular emphasis on regret minimisation over the last few years. The initial focus was on revealing which paradigm fits best for a given dataset, while later studies have looked at variation in decision rules across respondents within a dataset.
However, only limited effort has gone towards understanding the potential drivers of decision rules, i.e. what makes it more or less likely that the choices of a given respondent can be explained by a particular paradigm. The present paper puts forward the notion that unobserved character traits can be a key source of this type of heterogeneity and proposes to characterise these traits through a latent variable within a hybrid framework. In an empirical application on stated choice data, we make use of a mixed random utility-random regret structure, where the allocation to a given class is driven in part by a latent variable which at the same time explains respondents' stated satisfaction with their real world commute journey. Results reveal a linkage between the likely decision rule and the stated satisfaction with the real world commute conditions. Notably, the most regret-prone respondents in our sample are more likely to have aligned their real-life commute performance more closely with their aspirational values.

Bio: Stephane Hess is Professor of Choice Modelling in the Institute for Transport Studies and Director of the Choice Modelling Centre at the University of Leeds. He is also Honorary Professor in Choice Modelling in the Institute for Transport and Logistics Studies at the University of Sydney, and affiliated Professor in Demand Analysis at KTH Royal Institute of Technology in Stockholm. His area of work is the analysis of human decision using advanced discrete choice models, and he is active in the fields of transport, health and environmental economics. Hess has made contributions in the specification, estimation and interpretation of such models, notably in a valuation of travel time savings context, while also publishing widely on the benefits of advanced structures in actual large-scale transport analyses. His contributions have been recognised by a number of major awards. He is also the founding editor in chief of the Journal of Choice Modelling, the founder and steering committee chair of the International Choice Modelling Conference, and the co-chair for the14th International Conference on Travel Behaviour Research, to be held in London in 2015. He is an associate editor of Transportation Research Part E, and serves on the editorial advisory board of Transportation Research Part B and Transportation.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
12/12/2014 @ 12:15 room GC C330

Google or TomTom: Who is better?

Dr. Klaus Bogenberger, Universitiy FAF, Munich, Germany

Nowadays, traffic data are everywhere: Color-coded road maps showing the current traffic state or expected delays are available on smart-phones or computers, navigation devices include traffic data within der route computation and traffic messages inform car drivers via radio. However, the value of traffic information services depends on the quality of the used traffic data. Imprecise data lead to bad advices and thus to unsatisfied customers. But how can the data quality be rated and checked? The announced lecture provides a general introduction to the topic of traffic data, i.e., types of traffic data, their generation and typical sources for quality shortcomings. Furthermore, an overview of common methods for assessing traffic data quality is given and new, recently developed concepts and approaches are shown.

Bio : Dr. Klaus Bogenberger is an Full Professor at the University FAF in Munich since 2012. He received his Civil Engineering diploma and Doctoral Degree, from the Munich University of Technology (TUM). In addition, he was a visiting scholar at the University of California at Berkeley, at Institute of Transportation Studies. His PhD was about adaptive and coordinated ramp metering systems. Dr Bogenberger was a researcher at the BMW Group and a general Manager of a transportation consultancy before he returned to academia. Dr. Bogenberger's research interests lie in the areas of real-time traffic information, navigation, bike and car sharing systems.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
19/12/2014 @ 12:15 room GC C330

Rocking structures: Improved seismic assessment and design

Dr. Matthew DeJong, University of Cambridge

The rocking of structures during earthquakes is both essential to the assessment of existing structures and promising for the development of novel seismic design methods. Regarding assessment, the seismic collapse of masonry structures will first be considered, and will be used to introduce the fundamental characteristics of rocking motion. In this context, a new framework will be presented which aims to significantly improve code-based procedures for assessment of out-of-plane collapse.
Regarding seismic design, more stringent seismic performance objectives are inspiring new design methods which aim to reduce or locate damage, even for large earthquakes. One such method, which uses rocking to isolate the structure from the ground motion, will be considered. In particular, the relative importance of flexibility, the effect of rocking on elastic modal response, and the effect of near-source ground motion will be discussed. Shake table test results will also be presented. In general, the results provide a basis to improve current design methods.

Bio : Dr Matthew DeJong is a Lecturer in Structural Engineering at the University of Cambridge, where he leads a research group focused primarily on earthquake engineering and masonry structures. Prior to his current appointment, he earned his BS at UC Davis, his MS and PhD at the Massachusetts Institute of Technology, and he was a Fulbright Scholar at TU Delft. He has also worked as a structural engineering design consultant in California.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
20/02/2015 @ 12:15 room GC B3 30

Advanced Nonlinear Finite Elements For The Design and Assessment of Complex Concrete Structures

Prof. Dr Mahdi BEN FTIMA, École Polytechnique of Montreal, Québec, Canada / Visiting Professor at ENAC-MCS

Nonlinear finite elements for concrete structures have seen a remarkable advancement in the last half century with more emphasis on constitutive modelling or reinforced and non-reinforced concrete. Applications were restricted to the analysis of simple structures (beams, columns, slabs ...etc.), comparisons to experimental tests, and rarely extended to the design of complex structures. The reasons behind this fact and solutions to them will be addressed by the lecturer. A general methodology with computational, probabilistic and validation frameworks will be the core issue of the seminar. Applications from the industrial field of hydraulic structures, in which the author was involved in the last ten years, will be presented. Finally, the lecturer will provide an overview of his future research objectives as a newly hired professor at the École Polytechnique of Montréal.
Bio:
Mahdi BEN FTIMA is an assistant professor at the École Polytechnique of Montréal, in the civil, geological and mining engineering department, Group of Research in Structural Engineering (GRS group). He graduated from the École Polytechnique de Tunisie in the year 2000 and received his master and Ph.D degrees from the École Polytechnique of Montréal, respectively in 2004 and 2014. During the last ten years, he was involved as a structural engineer in the design of different large and complex hydraulic structures within the international SNC-Lavalin engineering firm (Hydro division of Montreal).

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
27/02/2015 @ 12:15 room GC B3 30

Mortar-based composites for seismic retrofitting of masonry

Prof. Gianmarco De Felice, Roma Tre University, Italy

New strengthening systems based on textiles externally bonded with mortar are currently used in seismic retrofitting of masonry structures. However, neither rules for the design of strengthening, nor regulation for the product qualification are yet available. With respect to classical FRP, these systems ensure a better compatibility and sustainability, but a lower bond to the substrate, which could affect the structural performances. The talk will address current experimental research on these systems, including recent shaking table tests to assess the seismic performance.
Bio:
Gianmarco de Felice is professor of structural engineering at Roma Tre University and chairman of the Technical Committee RILEM TC 250-CSM "Composites for Sustainable strengthening of Masonry". He has been in charge of projects on heritage conservation, such as the restoration of Abbey of San Clemente in Casauria supported by the World Monuments Fund after the 2009 L’Aquila earthquake, and the restoration of the Farnese Palace in Ischia di Castro, attributed to Antonio da Sangallo. His current research encompasses the seismic assessment of architectural heritage, the retrofitting of masonry and reinforced concrete structures, the modelling of soil-structure interaction in settlements induced by excavation, the development of strengthening systems with mortar-based composites.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
06/03/2015 @ 12:15 room GC B3 30

Traffic signal control and route choice, capacity maximization and stability

Prof. Dr Mike Smith, University of York, England

The talk will have two parts: A, B.

PART A: [Routeing + control] dynamics with just flows and green-times.
This talk outlines the P0 control policy in a model without queues. It is shown that under certain conditions this policy maximises network capacity.
Natural dynamical flow-only models of day-to-day re-routeing (drivers swap to quicker routes) is combined with day to day green-time response based on the responsive control policy P0 (see Smith (1979, 1980, 1987). It is shown that, for any steady feasible demand within this dynamical flow + control model, any (flow, green-time) solution trajectory cannot leave the region of supply-feasible (flow, green-time) pairs, costs are bounded, and throughput is maximised.

PART B: [Routeing + control] dynamics with flows and green-times and queues.
It will then be shown that, within a model with explicit queues, modified Varaiya (2013) and Le at al (2013) control policies do not have the above properties. We give a network and a steady demand within the capacity of the network for which there is no equilibrium consistent with either policy; in each case a dynamical [routeing + control] model has unbounded queues.
The paper shows that, in contrast, responsive P0 on this example network does give rise to a consistent equilibrium and a dynamical [routeing + control] model has bounded queues. (One possible extension of P0 ideas to include Macroscopic Fundamental Diagrams may be described briefly).

Bio :
Mike is Emeritus Professor of Mathematics at the University of York; he was awarded the Robert Herman Lifetime Achievement Award in 2007 for his work on the Mathematics of Transport.
Mike entered the University of York as a lecturer in Mathematics in 1964. Soon after, the construction of a wide ring road close to York City Centre (and the demolition of 450 houses) was proposed to reduce congestion in York.
Mike’s first paper (“Traffic control in a town with two ring roads”) was published in 1974. This showed how traffic control could be used to reduce congestion in York without constructing a wide inner ring and without demolishing houses.
In 1979 / 1980 Mike published a paper called “A Local Traffic Control Policy which Automatically Maximises the Overall Travel Capacity of a Road Network”. Since then he has spent many years extending this “magic” policy (called P0); showing how traffic control may be used to reduce congestion within an existing road network; while taking account of route choices.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
13/03/2015 @ 12:15 room GC B3 30

Water – Energy nexus: challenges and sustainability towards water smart grids

Prof. Dr Helena M. Ramos, University of Lisbon, Instituto Superior Técnico, Portugal

Abstract: The definition of suitable design criteria in hydraulic systems is of utmost importance and has become a priority for good design implementation. The dynamic behaviour of hydropower stations and the interaction with long hydraulic circuits are the major constraints for safety solutions. Water needs and energy saving have become concerns over the last years and it is expected to become more and more important in the near future due to the effect of the climate change on the water and energy sustainability. Following the fuel crises, hydropower has become one of the most important clean and renewable energy sources. Optimization methods are used to define the system operation, as well as economic analysis, while satisfying the system constraints and priorities. Pumped-storage solutions can be used to solve problems of energy production, as well as in the integration of intermittent renewable energies, providing system elasticity due to energy loads’ fluctuation, as long as the storage of energy from intermittent sources. Water supply systems present high-energy consumption values. Energy costs are a function of its consumption and of the variability of the daily energy tariff. The need for a better use of water and energy has been considered as one of the most important subjects towards future water smart grids.

Bio :
Helena M. Ramos has a Ph.D. degree and Aggregation title and is Associate Professor at Instituto Superior Técnico (University of Lisbon) at Department of Civil Engineering. She is expert in different scientific domains, including: Hydropower and Pumping Systems; Surge Control, Safety and Operation - Dynamic Effects; Computational Fluid Dynamics (CFD) - Hydrodynamic and Mathematical Modelling; Water and Energy Efficiency; Hybrid Sustainable Solutions; Optimization in Pumping/Turbine Management. She has more than 350 publications, being one book in small hydro, more than 60 in scientific journals with referee and 150 in international conferences. She has supervised several post-doc, PhDs and MSc students and she is author of eight innovative solutions in the domain of Civil Engineering - hydropower and hydraulic system control.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
20/03/2015 @ 12:15 room GC B3 30

Nonlinear analysis of composite steel-concrete cable-stayed bridges at service and ultimate states

Prof. José Oliveira Pedro, IST Lisbon University, Portugal (invited Professor at IIC spring 2015)

The nonlinear analysis of composite steel-concrete cable-stayed bridges is presented. The FEModel used for the composite deck, including the flexible shear connection between the concrete slab and the steel girders, are first presented.
Geometrical and material nonlinear behaviours of both steel and concrete materials are briefly discussed, as well as, the cable's sag and time dependent effects due to load history, creep, shrinkage and aging of concrete.
These main sources of nonlinearity are evaluated for a 420 m main span composite cable-stayed bridge, under service conditions.
The failure load and the failure mechanism are also analysed, both at the end of construction and at long term.
The influence of the following factors is presented: (1) deck load pattern, (2) time dependent effects, (3) cables' yielding and “cable-out” effect, (4) existence of intermediate piers at the lateral spans, (5) effective slab width, and (6) flexibility of the shear connection.

Bio : Graduation 1991, MSc in 1995 and PhD in 2007 from IST Lisbon. PhD Thesis entitled: L’analyse du comportement des ponts haubanés avec de tablier mixte acier-béton.
Since 1991, junior then senior engineer at GRID design office, participated in the design of over 50 bridge projects, and also stadiums, towers, and other special structures. In parallel, since graduation teacher and researcher at DEC (civil engineering department) of IST Lisbon University. Promoted assistant professor in 2007, specialist of steel, steel-concrete bridges and special structures.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
26/03/2015 @ 16:00 room SV1717A

Open Access - what's in it for you?

Julien Junod, EPFL scientific librarian, and Pierre Devaud, EPFL library team coordinator

What is Open Access, and how does it work? What are Green versus Gold journals, and how do you make your research visible without infringing the publishing laws? How can you share your work for free and improve your bibliometric record? Julien Junod and Pierre Devaud from the EPFL library team will answer all these questions and help you improve the visibility of your research. Please sign up here if you're interested.
The event will be followed by an apero in the SV Hall to continue discussions.

Organized by SV postdoc association in collaboration with the EPFL library.
27/03/2015 @ 12:15 room GC B3 30

Quasi-dynamic o-d flow estimation from traffic counts: results and research prospects

Prof. Dr Vittorio Marzano, assistant professor, University of Napoli, Italy
Prof. Dr Andrea Papola, associate professor, University of Napoli, Italy

The seminar reports on research results and prospects on origin-destination (o-d) flows estimation based on traffic counts.
Acknowledging that a satisfactory OD flow updating (regardless of the quality of the prior estimate) can be obtained generally only when the ratio between the number of equations (i.e. independent observed link flows) and the number of unknowns (i.e. OD flows) is close to one, a quasi-dynamic GLS o-d flow estimator from traffic count is presented, under the assumption that o-d shares are constant across a reference period, whilst total flows leaving each origin vary for each sub-period within the reference period. The advantage of this approach over conventional within-day dynamic estimators is that of reducing drastically the number of unknowns given the same set of observed time-varying traffic counts. The realism of the quasi-dynamic assumption, and the theoretical and operational properties of the proposed QD-GLS estimator are discussed and tested on the real test site of A4-A23 motorways in North-Eastern Italy.
Two concerned research prospects are discussed also: the former is the formulation of non-linear quasi-dynamic Kalman filters (QD-KF), embedding diverse specifications of the state variables and of the corresponding transition and measurement equations, with promising results on synthetic networks. The latter deals with a different approach for balancing unknowns and equations, that is proposing an optimal joint approach for zoning and o-d flow estimation/updating, i.e. achieving an effective trade-off between approximation in network loading pattern and effectiveness in o-d flow estimation.

Bios :
Vittorio Marzano is assistant professor at the University of Napoli, visiting researcher at the Singapore University of Technology and Design (SUTD), external collaborator of the SUTD-I3 innovation centre and affiliate with the Singapore-MIT Alliance for Research and Technology (SMART-MIT) and the ITS lab at MIT Boston. He holds a PhD in Transport Engineering from the University of Napoli (2006), a MPhil in Transport systems planning and management (2003) and an executive course in Supply chain management and distributive logistics from the Business School of the Politecnico di Milano (2010). His research interests cover various topics of transport engineering: freight modelling, discrete choice modelling, o-d flow estimation/updating, network sensors location, traffic assignment, ITS. He is referee for top international journals and peer-reviewed projects. He is involved in teaching activity for undergraduate and postgraduate courses and masters in Italy and abroad. He has an extensive track record of management of international research projects, and he has also joined more than 20 national/international research projects in quality of senior researcher. He has also a considerable consultancy experience in the sectors of freight and logistics, public transport, high-speed railways, feasibility studies of infrastructures and transport services in Italy and abroad.

Andrea Papola is associate professor of Methods and applications for transport system engineering at the University of Napoli “Federico II”. He holds a Ph.D. in Transport Engineering from the University of Napoli, past positions include a research fellowship at the National Research Council (1998-2001). His research interests, developed in more than 20 years of experience, include models and methods for simulating passenger and freight transport systems, advanced discrete choice models (especially for route choice), methods for effective o-d matrix estimation/updating, survey design and model estimation on the basis of RP/SP data. He has published 18 top journal papers, 7 chapters in international books and more than 40 conference proceedings, with an h-index of 7 and around 200 citations. He is member of the Editorial Advisory Board of Transportation Research Part B and was former member of the scientific committee of the European Transport Conference. He has a proven track record of undergraduate and postgraduate taught courses in national and international contexts. He has been invited to give presentations in several national and international universities. He was principal investigator in several EU and Italian funded projects. He has been in charge of implementing several decision support systems related to both passenger and freight transport systems, both at a national and regional level. He also carried out several feasibility studies for new infrastructures and services appraisal.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
17/04/2015 @ 12:15 room GC B3 30

Gravity currents flowing up a slope: laboratory experiments, shallow-water and Large Eddy simulations

Prof. Dr Claudia Adduce, University Roma Tre, Italy

Abstract: The dynamics of unsteady gravity currents propagating up a slope are investigated by laboratory experiments, shallow-water and Large Eddy Simulations. Different runs were carried out by varying the initial density of the lock fluid and the bed upslope. As a gravity current moves up a slope, the dense layer becomes thinner, and an accumulation region of dense fluid in the initial part of the tank occurs. The current speed decreases as the bed upslope increases, and for the highest up sloping angles, the gravity current stops before reaching the end of the tank. A two-layer shallow-water model is developed and benchmarked against laboratory experiments. The present model accounts for the mixing between the two layers, the free surface, and the space-time variations of the density. The effect of the horizontal density gradient in the simulation of gravity currents is investigated by comparing the numerical results of both the present model and the model proposed by Adduce et al. (2012) with laboratory measurements. The present model reproduces both the current shape and the front position better than the Adduce et al. (2012) model, in particular, for gravity currents flowing up a slope. Large Eddy Simulations are used to investigate the mixing processes between the dense current and the ambient fluid, revealing a decrease of mixing as the steepness of the bottom increases. The total energy budget is presented to highlight the effect of the up-sloping boundary on the flow dynamics. When a gravity current starts to develop, mixing strongly depends on the evolution of Kelvin-Helmholtz billows. When these structures lose their coherence, three-dimensional features of the flow appear more evident and cause mixing.

Bio :
Claudia Adduce is Associate Professor with tenure at the Department of Engineering of the University Roma Tre, Italy. She completed her PhD at the University Roma Tre and she worked at the Department of Physical Oceanography of Woods Hole Oceanographic Institution (USA). She teaches Environmental Hydraulics for Civil Engineers at the University Roma Tre. Her research focuses on: gravity currents, internal waves, eddies interaction with seamounts and islands, local scouring downstream of hydraulic structures, sloshing of stratified fluids.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
24/04/2015 @ 12:15 room GC B3 30

STRUCTURED FLEXIBLE TRANSIT SYSTEMS FOR LOW DEMAND AREAS

Prof. Dr Yanfeng Ouyang, Associate Professor University of Illinois at Urbana-Champaign (UIUC), USA

Public transportation is often viewed as a means to address congestion in urban areas. However, it also serves another equally important societal function: providing mobility to those who lack access to alternative modes of transportation. Traditionally, public transit networks contain fixed bus routes and predetermined bus stations. Such systems are often found unaffordable and even inaccessible in areas and/or time periods with low travel demand. This talk focuses on alternative “structured” flexible-route transit systems, in which each bus is allowed to travel across a predetermined area to serve passengers, while these bus service areas collectively form a hybrid “grand” structure that resembles hub-and-spoke and grid networks. We analyze the agency and user cost components of this proposed system in idealized square cities and seek the optimum network layout, service area of each bus, and bus headway, to minimize the total system cost. They compare the performance of the proposed transit system with that of comparable systems (e.g. fixed-route transit network and taxi service), and show how each system is advantageous under certain passenger demand levels. It is found out that under low-to-moderate demand levels, the proposed flexible-route system has the lowest system cost. At the end of the talk, some ongoing extensions of the proposed transit system will be briefly discussed.

Bio : Yanfeng Ouyang is Associate Professor, P.F. Kent Endowed Faculty Scholar of Civil and Environmental Engineering, and D.B. Willett Faculty Scholar at the University of Illinois at Urbana-Champaign (UIUC). He received his Ph.D. in civil engineering from the University of California at Berkeley in 2005. His research mainly focuses on transportation and logistics systems, infrastructure systems, traffic flow theory, and applications to energy, sensor, and agricultural systems. He currently serves as a Department Editor of IIE Transactions, an Area Editor of Networks and Spatial Economics, an Associate Editor of Transportation Science, an Associate Editor of Transportmetrica B, and a Guest (Co-)Editor of Transportation Research Part B, Journal of Intelligent Transportation Systems, and the International Journal of Rail Transportation. He is on the editorial advisory board of Transportation Research Part B and the Journal of Infrastructure Systems. He received a Faculty Early Career Development (CAREER) Award from the U.S. National Science Foundation in 2008, a Walter L. Huber Research Prize from the American Society of Civil Engineers in 2015, a High Impact Project Award from the Illinois Department of Transportation in 2014, an Engineering Council Outstanding Advisor Award from UIUC in 2014, a Xerox Award for Faculty Research from UIUC in 2010, and a Gordon F. Newell Award from Berkeley in 2005.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
01/05/2015 @ 12:15 room GC B3 30

Advanced computational models for structural mechanics

Prof. Dr Mohammed HJIAJ, INSA Rennes, France

Devising practical design rules requires both experimental results and rigorous computational models that are first validated and next used to explore other situations by performing extensive parametric study that cover all possible cases. This presentation will touch on two very different problems (buckling of hybrid columns and impact of steel beam) and show how computational models can be used to derive design rules particularly for problems where tests are expensive.

The first part of the talk deals with numerical investigations on second-order effects in slender RC columns reinforced by several steel sections, namely hybrid columns, subjected to combined axial load and uniaxial bending moment. New expressions for the correction factors involved in the determination of the effective flexural stiffness EI are proposed and calibrated by the results of the extended parametric study with 2960 data sets.

In the second part of the talk, we develop a computational model for the analysis of a column impacted by a projectile. The formulation of impact problems can be divided into two groups: smooth and non-smooth approaches, which we will compare. For both formulations, we use a newly developed energy-momentum time integration scheme to ensure conservation of the total energy and the momentum of the system during and after the impact.

Bio : Professor Mohammed HJIAJ is head of the Structural Engineering Research Group at INSA de Rennes (FRANCE). He graduated with honors from Ecole Centrale des Arts & Métiers (Brussels) in 1990 with a B.S. in Civil Engineering. He obtained an M.Sc. degree in Mechanics of Solids and Structures from Faculté Polytechnique de Mons (Belgium) in 1992. In 1994, he joined the Civil Engineering Department at Ecole des Mines de Douai in France as a lecturer. There he conducted research on computational plasticity, error analysis and adaptive strategies. After receiving his Ph.D. degree from Faculté Polytechnique de Mons in 1999 with the highest distinction, he joined the CNRS as a Research Scientist, where he pursued research on computational mechanics dealing with non-smooth problems. In Fall 2000, he moved to the University of Newcastle (Australia) where he pursued research on computational limit and shakedown analysis with application to foundation engineering and soil-structure interaction. In 2002, he was awarded the Australian Post-Doctoral Fellowship from the Australian Research Council to work on a variety of topics related to computational geomechanics. In September 2004, he was appointed Professor at INSA de Rennes, where he conducts experimental and computational research on steel and composite steel-concrete structures, including seismic behavior and robustness. He serves on various technical committees within the ECCS, is on the editorial board of the French journal Construction Métallique and an associate editor for the ASCE Journal of Structural Engineering.

The Group research ID:

The Structural Engineering Research Group has a long tradition of research in steel and composite structures. Much of our research projects involve a combination of experimental, theoretical and computational work. The group has extensive expertise and knowledge in both computational structural mechanics including its theoretical foundations and advanced testing of structures. Over the years, the group was at the forefront of developing Finite elements for high nonlinear and sophisticated structural problems able to closely reproduce the behavior of structure as observed experimentally with the aim to provide engineers with appropriate tools for advanced design (pre-normative research). Elastic and inelastic time-independent as well as time-dependent problems have been addressed.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
08/05/2015 @ 12:15 room GCB330

Tsunami Impacts on Structures

Prof. Dr Ioan Nistor, Associate Professor at University of Ottawa, Canada

Abstract:
On March 11, 2011, a magnitude 9.0 earthquake occurred along the Sanriku Coast, offshore north-east Japan, at 3:46 p.m. local time. The earthquake generated massive tsunami waves which hit the Japanese coast, reaching up to 45 meters of runup. Significant damage occurred in coastal and inland engineered structures located in several coastal towns that were largely destroyed. The first international research team composed of group of four researchers (three from US and one from Canada), visited the affected area four weeks after the event to conduct reconnaissance field investigations on behalf of the American Society of Civil Engineers (ASCE). Dr. Ioan Nistor, a coastal engineering professor at the Department of Civil Engineering of the University of Ottawa, was a member of this field reconnaissance team and will present findings on the performance of infrastructure and the damage induced by tsunami waves.
The lecture may be of interest to hydraulic, structural and geotechnical engineers interested in disaster prevention and mitigation, with a particular emphasis on the design of structures prone to extreme hydrodynamic loading due to tsunamis, extreme waves, and flash floods.

Bio :
Dr. Ioan Nistor is an Associate Professor of Hydraulic and Coastal Engineering in the Department of Civil Engineering of the University of Ottawa with both academic and consulting engineer experience. He is currently working on hazards associated with extreme hydrodynamic loading on infrastructure (tsunamis, flash floods) as well as blast-induced loading. He obtained his Dipl. Eng. degree in Hydrotechnical Engineering from the Technical University Iasi, Romania in 1991 and his PhD in Coastal Engineering in 1998 from Yokohama National University, Japan. He is currently the Chair of the Maritime and Coastal Division of International Association for Hydro-Environment Engineering and Research (IAHR) and a member of the Board of Directors of the Canadian Coastal Science and Engineering Association. He is also a Voting Member of the ASCE7 Tsunami Loads and Effects Subcommittee for the elaboration of New Design Guidelines for Tsunami-Resistant Buildings.

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
29/05/2015 @ 12:15 room GC B3 30

What if we could minimize financial loss from earthquakes….

Prof. Rajesh Dhakal, University of Canterbury, Christchurch, New Zealand

Synopsis

In the last century, seismic design has undergone significant advancements. Starting from the initial concept of designing structures to sustain no or minimal damage during an earthquake, the modern seismic design philosophy allows structures to respond to ground excitations in an inelastic manner, thereby allowing damage in earthquakes that are significantly less intense than the largest possible ground motion at the site of the structure. Current performance-based multi-objective seismic design methods aim to ensure life-safety in large and rare earthquakes and to limit structural damage in frequent and moderate earthquakes. As a result, not many recently built buildings have collapsed and very few people have been killed in 21st century buildings even in large earthquakes. Nevertheless, the financial losses to the community arising from damage and downtime in these earthquakes have been unacceptably high. This has raised a new question; “what if we could minimize financial loss from earthquakes?”

It was well-known before the earthquakes that our old and unreinforced masonry (URM) building stock was seismically deficient and needed urgent intervention to enhance their performance. These buildings were not expected to come out unscathed after such severe shakings. Still, it was very unfortunate that collapse of some of our old buildings resulted in significant loss of life. Nevertheless, modern buildings built in the 21st century using the current design philosophy in general did better than what they were expected to do in much severer shakings than they were designed for. Consequently, some engineers have been (justifiably) claiming that the performance of building stock in the Canterbury earthquakes was generally better than expected. This has perplexed the general public, who has been reading in media the continually growing amount attributed as earthquake induced cost. They may be pondering: “How can the engineers say we have done well? Do we need to go broke before they realize we have failed miserably?” This difference is mainly because of the different expectations of the engineers (life-safety) and the general public (economic consequences). Hence, it is high time that the seismic design objectives be matched in line with public expectations.

In this pretext, the seminar will try to answer the following questions:

What unexpected did we observe in recent earthquakes and did we learn anything new?
Why is current earthquake-resistant design approach unable to minimize loss?
How is structural performance related to loss?
How can we reduce loss from earthquakes?
Where to in future?

Bio : Prof Rajesh Dhakal has a Bachelor degree in Civil Engineering from Tribhuvan University, Nepal, Master of Structural Engineering from the Asian Institute of Technology, Thailand, and a PhD from Tokyo University, Japan. His research interests are in the areas of seismic performance of reinforced concrete structures; non-structural elements; and seismic loss estimation. He has supervised more than postgraduate (ME/PhD) students and has authored more than 250 technical papers in the areas of reinforced concrete, earthquake engineering, and structural fire engineering. He has received multiple research awards including the prestigious EQC-NZSEE Ivan Skinner award for the advancement of earthquake engineering research in New Zealand. He is a fellow of IPENZ (Institution of Professional Engineers in NZ). He served as an Associate Editor for the ASCE Journal of Structural Engineering from 2007 to 2013, and is currently the chief Editor of the Bulletin of the NZ Society for Earthquake Engineering (NZSEE).

Organized by Prof. Dr Nikolas Geroliminis & Katrin Beyer
05/06/2015 @ 14:15 room PH L1 503 (The aquarium )

Toward quantum dot based quantum networks

Dr. Pascale Senellart, CNRS

Semiconductor quantum dots (QDs) are very promising artificial atoms for quantum information processing; they can generate flying quantum bits in the form of single photons or polarization entangled photon pairs. They show single photon sensitivity, which can be used to implement quantum logic gates; and, last but not least, the spin of a carrier trapped in a QD can be used as a quantum memory. The scalability of a QD based quantum network requires having efficient interfaces
between stationary and flying quantum bits. In the last few years, our group has made significant progresses in this direction using cavity quantum electrodynamics.

By deterministically positioning a single QD in a microcavity, we control its spontaneous emission at will [1]. With such a tool, we fabricate ultrabright sources of single photons and of entangled photon pairs, with brightnesses as high as 80% [2]. By controlling the charge environment of the QD in a gated structure [3], we demonstrate near unity indistinguishability of the emitted photons.

Symmetrically, we have made important progresses in the development of an efficient interface between a flying quantum bit and a stationary one. We show that a single spin in a cavity can macroscopically rotate the polarization of photons [4] and reach the regime where coherent control of a quantum bit can be done with only few photon pulses.

Bio: Directrice de Recherche CNRS
Laboratoire de Photonique et de Nanostructure
November 2012 – Present (2 years 8 months)

LPN carries out its research activities within the general context of nanosciences, at the cross-roads of quantum optics and electronics, of physics, chemistry and biology, of materials science and device physics. LPN develops the new technologies and the concepts that will initiate innovation both in basic and in applied science.

Organized by Arnaud Magrez and Raphaël Butté
18/06/2015 @ 16:15 room BC 129

Using Space Syntax as a Catalyst for Change. Thinking Critically Towards Excellence in School Buildings

Teresa Valsassina Heitor

The lecture will explore the input offered by a Space Syntax approach to manage the design brief in the scope of school building rehabilitation. The research question is focused on Space Syntax contribution to thinking critically on the fundamentals that are embedded into the design brief in order to facilitate communication between designers and non-designers involved in a collaborative design process.

Organized by LDM/SINLAB
25/09/2015 @ 12:15 room GC C3 30

Energy Geotechnology – Enabling New Insights Into Soil Behavior

Prof. J. Carlos Santamarina, KAUST (King Abdullah University of Science and Technology) Saudi Arabia

Energy is critical to life. The coming decades will see worldwide population growth and associated economic development that will result in a pronounced increase in energy demand. Historically, geotechnical engineering has been crucial to projects that have sustained societal transformations. Once again, geotechnical engineering has a central role to play in the evolving energy challenge, from resource recovery and infrastructure development, to energy storage and waste management. Examples during this lecture show that the emerging field of energy geotechnology drives us to reconsider the basic tenets of geotechnical engineering (such as soil formation, index properties, and classification), to extend our understanding of geomaterials (at high pressure and temperature, long time scales, and large number of repetitions), to recognize new phenomena (most often couplings between hydraulic, thermal, chemical, biological and mechanical processes, and various forms of localization), and to advance technological innovations for characterization (in situ, sampling, and laboratory) and monitoring.

Bio: J. Carlos Santamarina graduated from Universidad Nacional de Córdoba (Ingeniero Civil), and completed graduate studies at the University of Maryland (MSc) and Purdue University (Ph.D.). He taught at NYU-Polytechnic, the University of Waterloo (Canada), and Georgia Tech. Two books and 300 publications summarize salient concepts and research results. His former students are faculty members at more than two dozen universities, researchers at national laboratories, or practicing engineers at leading organizations worldwide. Dr. Santamarina is a frequent keynote speaker at international events, a member of both Argentinean National Academies (Sciences and Engineering), and has participated in several Committees at the USA National Academies. He is a recipient of the ASTM Hogentogler Award; he was the 2012 British Geotechnical Association Touring Lecturer; and he delivered the 50th Terzaghi Lecture in 2014.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
02/10/2015 @ 12:15 room GC C3 30

Who trigger green traffic light? - a robust and predictive urban traffic control solution

Prof. Dr Balazs Kulcsar, Associate Professor, chalmers University of Technology, Gothenburg, Sweden

The aim of the presented research is to elaborate a traffic-responsive optimal signal split algorithm taking traffic flow uncertainty into account. The traffic control objective is to minimize the weighted link queue lengths within an urban network area. The control problem is formulated in a centralized rolling-horizon fashion where unknown but bounded demand and queue uncertainty influences the prediction. An efficient, constrained minimax optimization is suggested to obtain the green time combination which minimizes the objective function when worst case uncertainty appears. As an illustrative example, a simulation study is carried out to demonstrate the effectiveness and computational feasibility of the robust predictive approach. By using real-world traffic data and microscopic traffic simulator, the proposed robust signal split algorithm is analyzed and compared to well-tuned fixed-time signal timing and to nominal predictive solutions under different traffic conditions.

Bio : Balazs KULCSAR received the Msc in transportation engineering and the PhD in automatic control from Budapest University of Technology (BUTE), Hungary. He worked as a researcher for the Department of Control for Transportation and Vehicle Systems, BUTE and for the Aerospace Engineering and Mechanics Department at the University of Minnesota, USA. After being a postdoctoral associate with Delft Center of Systems and Control, Delft University of Technology, The Netherlands, he became an assistant and later on an associate professor with Automatic Control group at the Department of Signals and Systems, Chalmers University of Technology in Gothenburg, Sweden. His main research interest encompasses traffic flow modeling and control with an inclination to incident/failure diagnosis.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
09/10/2015 @ 12:15 room GC C3 30

Detecting and Modelling the Decoy Effect in Transportation

Prof. Angelo Guevara, Universidad de los Andes, Santiago, Chile

Empirical evidence suggests that, under some circumstances, the introduction of a new option in a choice-set can increase the choice probability of other alternatives. This result, known as the decoy effect, defies the basic regularity assumption, which is at the root of standard models of choice that are based on a compensatory approach under the Random Utility Maximization (RUM) framework. The goal of this research was threefold. First, we worked toward the development of a practical probabilistic choice-model that could account for the decoy effect, building upon various types of choice behaviors that that been described in cognitive psychology. Then, we used the proposed choice model to study, with Monte-Carlo simulation, the power of different statistical tests for detecting the presence of this phenomenon. Finally, we designed and applied a Stated Preferences (SP) survey to detect and to characterize the decoy effect in route choice. Results of this research showed first that all the decoy effect types that have been described in the literature, can be replicated by the Random Regret Minimization (RRM) discrete-choice model. Regarding statistical testing for the presence of the decoy effect, we found that McNemar and Proportions tests showed larger power when the effect size was modeled as RRM. Finally, four conclusions were driven from the application of the SP survey. The first was that the decoy effect was present in route choice, but that it was hard to detect it in the context of commuting trips or when alternatives were far from the true trade-off line. The second result of the SP experiment was that the magnitude of the average sample effect obtained from it was coherent with a data generation process based on the RRM model. Third, the SP survey showed that the larger decoys found were of the compromise type, and that the more robust ones were those of the range type. Finally, the SP survey indicated that, although an emergent-values Logit model showed slightly better fit, the RRM had substantially superior performance in outer-sample forecasting. This final result suggests that the RRM does capture, to some extent, the underlying behavior that is causing the decoy effect, but that this choice-model may still be somehow incomplete for this purpose. Four future steps of this line of research can be identified. The first is to improve the RRM model. The second step corresponds to the design and application of a Revealed Preference (RP) experiment to detect the decoy effect in real transportation behavior. The next, is to deepen the analysis of the circumstances under which the decoy effect occurs. The final step corresponds to the study of possible transportation public policies that can benefit from the decoy effect, such as seated-only buses to favor the use of public transportation or different pricing strategies.

Bio : C. Angelo Guevara is associate professor at Universidad de los Andes in Chile; research affiliate of the Intelligent Transportation Systems (ITS) laboratory at the Massachusetts Institute of Technology (MIT); and external affiliate of the Choice Modelling Centre (CMC) at the University of Leeds. He holds an MSc in transportation from Universidad de Chile, as well as an MSc and a PhD in the same area from MIT. He has been awarded the Fulbright and the Martin-Family fellowships, as well as the honorable mention of IATBR's Eric Pas dissertation prize. His main research interest is in the modeling of choice behavior, with recent contributions on endogeneity, sampling of alternatives, behavioral economics.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
16/10/2015 @ 12:15 room GC C3 30

Behavior of Reinforced Concrete Elements subjected to Tri-Directional Loads

Ashraf Ayoub, Ph.D., P.E., FACI, Royal Academy of Engineering Chair and Professor, City University London

The two-dimensional design and behavior of typical reinforced concrete (RC) structures has been extensively studied in the past several decades. Such design requires knowledge of the constitutive behavior of reinforced concrete elements subjected to a biaxial state of stress. These constitutive models were accurately derived from experimental test data on representative reinforced concrete panel elements. The true behavior of many large complex structures however, requires knowledge of the constitutive laws of RC elements subjected to a triaxial state of stress. The goal of the proposed work is to develop new constitutive relations for RC elements subjected to a triaxial state of stress. To accomplish this task, large-scale tests on representative concrete panels need to be performed. An experimental program was conducted using a state of the art panel tester in order to evaluate the behavior of reinforced concrete elements subjected to tri-directional loads. The results of several full scale RC elements subjected to tri-directional shear loads are discussed. The tests revealed that the application of out-of-plane shear loads clearly reduced the in-plane shear strength. Based on these results, an interaction diagram between the three tri-directional shear stresses acting on a reinforced concrete element was developed. An element-based approach was then adopted in which these constitutive relations were integrated using the finite element method to predict the overall behavior of the entire structure. The newly developed three-dimensional finite element model is based on mixed fiber beam-column formulations, in which the new constitutive laws are accounted for at the fiber level. The model is currently being extended to account for different material and geometric nonlinear effects. The presentation concludes with correlation studies of RC columns subjected to three-dimensional static and dynamic loads. Theses studies proved the newly developed model can provide reasonable estimates when compared to experimental results.

Bio : Prof. Ayoub holds the Royal Academy of Engineering Pell Frischmann Chair of Nuclear Infrastructure at City University London, UK. He obtained his MSc and Ph.D. in Civil Engineering from the University of California-Berkeley and was a Post-Doctoral fellow at Stanford University. He is a Fellow of the American Concrete Institute; a past chair of Joint ACI-ASCE Committee 447, Finite Element Analysis of Reinforced Concrete Structures, and the ASCE committee on Emerging Computing Technologies. He currently serves as associate editor for the Journal of Structural Engineering, ASCE. His current research is in the field of design and analysis of nuclear infrastructure systems, nonlinear finite element analysis, constitutive modeling of materials through experimental and analytical techniques, earthquake engineering, and design of Fiber Reinforced Polymer composite systems. He was previously on the faculty at the University of Houston and the University of Missouri-Rolla, USA.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
23/10/2015 @ 12:15 room GC C3 30

Measuring the effect of social conformity in individuals' preference for electric vehicles

Prof. Elisabetta Cherchi, Associate Professor, DTU, Lyngby, Denmark

According to Crutchfield (1955) individuals consciously or unconsciously tend to "yield to group pressures" and consequently to act in agreement to the majority position. Social conformity has been extensively studied in psychology with also several applications to transport problems. Field experiments are typically used to evaluate the impact of social influence on self-reported changes toward environmentally sustainable transport behaviours. In this research, we discuss various aspects of social conformity and present a stated preference experiment set up to measure their effect on individual preferences. The choice of electric cars is used as an illustrative example. In particular, we explicitly measure how individuals' preference change before and after they have received social information on other's experience about driving range, about the need to adapt the activity schedule and about the benefit of parking policies. The effect of descriptive norm and other-signalling concern are also measured as part of the stated preference experiment, while injunctive norms are measured with typical statements on a 7-point Likert scale. Results from the estimation of mixed logit model and hybrid choice models, clearly confirms that the experience (especially negative) of other people has a powerful effect on individual preferences for range and parking policies. Results also confirm that individuals' behaviour is affected by the image they want other people to have of them, making them "more honest" in their answers.

Bio : Elisabetta Cherchi is Associate Professor at the Department of Transport, Technical University of Denmark, where she is also Deputy Head of the Ph.D. school in Transport. She is Area Editor of Transportation, and member of the editorial board of Transportation Research part B, Journal of Choice Modelling and Transport Policy. She is also Secretary and Treasurer of the International Association for Travel Behaviour Research (IATBR). Her research interest is in data collection, in the behavioural background of demand modelling and in how to use and expand it to study emerging problems such as understanding what drives sustainable transport behaviour and how it can be promoted.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
30/10/2015 @ 12:15 room GC C3 30

Adaptive Building Structures for Whole Life Energy Savings

Gennaro Senatore, EngD Candidate University College London, U.K.

Designing structures with minimal environmental impact is now a serious concern in the construction sector. Active control has been used in civil engineering structures for a variety of purposes. The most widespread application so far has been in vibration control. The potential of using adaptation to save material mass and crucially whether the energy saved by using less material makes up the energy consumed through control and actuation is a question that has so far received little attention.
Gennaro Senatore developed a design method that produces an optimum adaptive structure that minimizes the total energy spent throughout the whole life of the structure (embodied in the materials + operational). In a conventional design, members are sized based on a worst case scenario i.e. the maximum expected load combination. If embodied energy is to be saved, clearly, member sizing should not be governed directly by this worst load combination but by some fraction of it. As the loads approach their worst values, passive members will reach their capacity. Then strategically located active elements (actuators) provide controlled output energy in order to manipulate actively the internal flow of forces and stresses. In this way stresses can be homogenized and deflections kept within desired limits. The actuators are only activated for compensation of the displacements and internal forces when the loads reach a certain threshold. Therefore operational energy is only used when necessary. The research to date has successfully demonstrated that up to 70% reduction in structural weight and 50% of total life energy (embodied and operational) was achievable on truss like structures. In addition, using this method it is possible to achieve very slender structures that would not possible to design and build with conventional methods.
A large scale prototype structure was built to validate the numerical findings and investigate the practicality of the method. The prototype is an ultra-slender 6m (length) x 0.8m (width) x 0.15m (depth) (40:1 span to depth) cantilevered truss structure controlled in real-time to maintain serviceability conditions under loading. The structure is 80% lighter than an equivalent passive one, the data gathered from the experiments in terms of energy savings confirm the numerical findings obtained with the simulations.

Bio : Gennaro Senatore is a researcher and designer specialized in computational methods for the design and realization of complex forms and structures. He developed a novel formulation for the design and control of adaptive building structures: high performance structures (light-weight, energy efficient and increased slenderness) capable of counteracting loads actively by means of actuators, sensors and control intelligence. He built a full scale prototype of an adaptive truss structure at the University College London structures laboratory. He also developed a mathematical formulation for an interactive real-time physics engine as aid for teaching structural engineering. The mathematical model was implemented as the java applet Push¬MePullMe and later as the iOS app Make A Scape both distributed free of charge and currently adopted by several universities world-wide. He previously was the head of computational design and research for the engineering practice Expedition Engineering.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
03/11/2015 @ 17:30 room BC 02

OPEN SCIENCE WORKSHOPS 2015

Tuesday 3rd November: Amir Hesam, Scientific Advisor (Audiovisual Communications Laboratory, EPFL) and Robin Scheibler, Doctoral Assistant, (Audiovisual Communications Laboratory, EPFL)
Thursday 12th November: EPFL Library team
Tuesday 17th November: Sarah Jones, Senior Institutional Support Officer (Digital Curation Center)
Thursday 26th November: Renaud Richardet, PhD candidate, (Projet Human Brain, EPFL)

EPFL Library is pleased to invite you to the “Open Science Workshops 2015”. The goal of these events is to promote Open Science, Open Access and Open Data movements and support their sustainability. The workshops will take place on November 3rd, 12th, 17th and 26th 2015, from 5.30pm to 7.30pm, at EPFL Campus (BC 02).

The goal of these events is to promote Open Science, Open Access and Open Data movements and support their sustainability. During the workshops, participants will discuss about Open Science evolutions, challenges and stakes. After a short theoretical introduction, participants will experiment software/applications through practical exercises.

Tuesday 3rd November
“Reproducible Research using IPython interactive publications” by Amir Hesam, Scientific Advisor (Audiovisual Communications Laboratory, EPFL) and Robin Scheibler, Doctoral Assistant, (Audiovisual Communications Laboratory, EPFL).

Thursday 12th November
“Open access publication: the Good, the Bad and the Ugly” by EPFL Library team

Tuesday 17th November
“DMPonline workshop” by Sarah Jones, Senior Institutional Support Officer (Digital Curation Center)

Thursday 26th November
“Data/Text Mining” by Renaud Richardet, PhD candidate, (Projet Human Brain, EPFL)

Each workshop can host 40 participants, so if you want to take part in your favourite workshop, make sure you register now! You may register for one, two, three or all four workshops - Registration

We are looking forward to meeting you on November 3rd, 12th, 17th and 26th 2015!

Webpage of the event
Registration form
questions.bib@epfl.ch or (+41) 21 693 21 56

Organized by Bibliothèque de l'EPFL
13/11/2015 @ 12:15 room GC C3 30

Submarine sediment density flows and their impact on subsea infrastructure: How far, how fast, how dense?

Benoit Spinewine. Senior Engineer, Team Leader Seabed Mobility at Fugro GeoConsulting and Guest Lecturer at Université catholique de Louvain, Belgium

With the gradual depletion of nearshore resources and technological advances in oil and gas production, developments are now often located further offshore beyond the continental shelf, in environments of steeper slopes susceptible to mass movement events. The presentation highlights the motivation behind the development of numerical models capable of simulating the dynamic evolution of submarine sediment density flow events from inception to runout, and the implications of the flow dynamics in terms of the level of risk imposed on subsea infrastructure upon impact. At first, the presentation highlights the types of submarine sediment density flows of engineering significance, and discusses some of the key questions that remain to be addressed by further research. It then introduces two depth-averaged, two-dimensional models for debris flow runout that rely on radically different solution methods (Smoothed Particle Hydrodynamics and the Finite Volume Method). The models can both utilize non-linear rheological soil models, and have the capability to include mechanisms for strength degradation resulting either from strain accumulation or the entrainment of ambient fluid. The two models are cross-validated on an hypothetical test case, and then used to illustrate the effect that soil rheology may have on the flow conditions at the point of impact against a pipeline. It highlights the crucial role of flow viscosity, and more generally, the importance of a proper rheological characterization for the purpose of impact analyses. It also discusses modelling of the dynamic structural response of a pipeline to flow impact, using the finite element suite Sage Profile 3.0. The presentation then discusses ongoing developments aimed at proposing a unified framework for debris flow/turbidity current modelling using a two-layer approach.

Bio : Benoit Spinewine obtained his PhD in Civil Engineering from the University of Louvain-la-Neuve, Belgium, on dam-break induced sediment transport. He then spent two years at the University of Illinois working on submarine turbidity currents. He has tackled the related challenges by combining experimental investigations, specialized numerical techniques, and field applications. He has over 10 years’ experience in applied and fundamental research, has authored 18 journal publications and over 50 communications at specialty conferences and congresses. While maintaining a guest-lectureship at University of Louvain-la-Neuve on coastal & maritime hydraulics and computational methods, he is now mainly applying his expertise on offshore industry projects at Fugro GeoConsulting.

Organized by Prof. Brice Lecampion & Katrin Beyer
20/11/2015 @ 12:15 room GC C3 30

Personalized Design of Mechanically-Functional Content for 3D Printing

Dr Bernhard Thomaszewski, Research Scientist, Disney Research, Zurich, Switzerland and adjunct lecturer at ETH Zürich

As a key advantage over conventional manufacturing technologies, 3D printing has the ability to create complexity and variety at no extra cost. This fact indicates the possibility of a mass customization culture in which we personalize designs according to our needs and preferences and fabricate them at home on a 3D printer. But while there is already a thriving market of consumer-level 3D printers, the tools that would empower average users to design 3D-printable content are still largely lacking.
In this talk, I will highlight a number of challenges that arise when creating such tools and illustrate some key concepts on the example of physical characters such as mechanical toys, robotic creatures, and other mechanically-functional models. In particular, I will address the question of how to design mechanisms that are able to reproduce desired motions, and how to create robotic creatures that can locomote in stable and compelling ways.

Bio:
Bernhard Thomaszewski is a Research Scientist at Disney Research Zurich, where he leads the group on Computational Design and Digital Fabrication. He obtained his Master’s degree (Diplom) and PhD (Dr. rer. nat.) in Computer Science from the University of Tübingen. Prior to joining Disney Research, he was a postdoctoral researcher at ETH Zürich, where he is an adjunct lecturer today.
Bernhard's research interests are in the areas of computational design, digital fabrication, and computer animation. His current focus is on design tools that allow non-expert users to create functional content for digital fabrication devices.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
27/11/2015 @ 12:15 room GC C3 30

Civil Engineering Structures Incorporating Advanced Composite Materials

Dr Wendel Sebastian, Reader in Structural Engineering, University of Bristol, United Kingdom

Due to their high stiffness-to-weight and strength-to-weight ratios, along with their corrosion resistance, advanced composites (commonly glass and carbon fibre reinforced polymers) are well-established as renowned structural materials in high-level aerospace and automotive applications. For similar reasons these materials show strong potential for cost-effective life extension of existing Civil Engineering structures (e.g. buildings and bridges), and also, in combination with traditional construction materials, for economic new-build of light, rapidly assembled bridges with potentially enhanced durability. In these Civil Engineering applications, the key is to develop solutions which exploit the properties unique to advanced composites. This requires investigation of the underlying mechanics of structures incorporating these exciting materials. The talk will describe research at Bristol University focused on such mechanics. The two examples chosen – one for existing structures, the other for new-build – will illustrate the following concepts, namely :
• The benefit of sometimes inverting design philosophy - from strengthening to stiffening - at the ultimate limit state.
• Long-term effects due to local interaction between lorry tyres and bridge decks made of these novel, anisotropic composite materials

Bio : Dr Wendel Sebastian is a Reader in Structural Engineering at the University of Bristol. His research on composite structures spans from road bridges made wholly or partly of advanced composite materials, to timber-concrete composite floors for buildings. He has led multiple projects entailing tests at different scales (from material coupons to full-scale bridges) in the laboratory, in parallel with nonlinear numerical analyses and, recently, field testing and remote monitoring of in-service road bridges with advanced composite decks. An important feature of these projects is the feeding of research outputs into existing design guidance (e.g. TR55 for advanced composite strengthening of concrete structures, or the emerging European technical document for new-build advanced composite bridges).

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
11/12/2015 @ 12:15 room GC C3 30

FRP bridges in Spain during the last decade

Dr Carlo Paulotto, Head of Structural Design Group at Technological Centre of ACCIONA infraestructuras, Madrid, Spain

In the last three decades, the use of fiber-reinforced polymer (FRP) materials in bridge manufacturing has attracted the interest of the civil engineer community due to three reasons at least: (i) FRPs may help reducing the maintenance costs of bridges due to the fact that they do not suffer from galvanic corrosion; (ii) the weight of FRPs, normally between 15 and 20 kN/m3, offers the chance of manufacturing bridges which weigh less than those built using traditional materials. This is especially useful in remote areas, since the transport and installation of the bridge girders are simplified; (iii) the light weight of FRP structural members simplifies their transportation and installation then fostering their prefabrication. Their high levels of prefabrication and lightness help speeding up the construction process of bridges and, as a consequence, reducing traffic congestions caused by site activities, which is nowadays a priority for many bridge construction projects. The seminar illustrates the design concepts and manufacturing processes of a series of vehicular and pedestrian bridges built by ACCIONA Infraestructuras in the last two decades using FRPs. The lessons learnt from each of these projects are highlighted, and the consequent improvements introduced in the design and manufacture of the FRP girders in order to reduce their costs are addressed: open sections instead of closed sections, glass-carbon fiber laminates instead of full carbon fiber laminates, resin infusion instead of hand lay-up. The case of a footbridge in which carbon fiber cables have been used as the main load-bearing system is presented as well. Other applications of FRPs to marine structures and tunnel linings are also briefly described.

Bio : Dr Carlo Paulotto currently works at the Technological Centre of ACCIONA Infraestructuras, located in Madrid (Spain), as head of the Structural Design Group. He received his Master Degree in Civil Engineering from the Sapienza University of Rome in 2000 and his Ph.D. in Structural Engineering from the same university in 2003. After some years spent as research assistant at that university and as postdoctoral fellow at the European Laboratory for Structural Assessment (ELSA) in Ispra (Italy), he joined ACCIONA Infraestructuras in 2007. Since then he has been involved in the design and manufacture of all the company’s FRP elements.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
18/12/2015 @ 12:15 room GC C3 30

Seismic soil-structure interaction and the nonlinear response of shallow foundations

Dr António A. Correia, Researcher at Earthquake Engineering and Structural Dyanmics, Portuguese National Laboratory for Civil Engineering (LNEC), Lisbon, Portugal

The interaction between a superstructure, its foundation and the supporting terrain may have a strong influence on the seismic response of structures. An overview of soil-structure interaction (SSI) phenomena and effects in the linear elastic range will pave the way for a presentation of recent research work that contributes to clarify the effects of nonlinear dynamic interaction on the seismic response of soil-foundation-superstructure systems. Such work includes several experimental results of seismically loaded structures on shallow foundations.
Theoretical advancements are also presented, in relation to macro-element numerical modelling of the soil-foundation system. These macro-element models represent the nonlinear soil behaviour at near-field and the ground substratum dynamic characteristics at far-field, as well as the interaction with the seismic response of the structure. All aspects of elastic and inelastic behaviour of the foundation system are thus encompassed into one computational entity and are described by the behaviour of a single point at the centre of the foundation.
These developments are then used for supporting the concept of a controlled share of ductility demand between the superstructure and the foundation as a key ingredient for a rational and integrated approach to seismic design of foundations and structures. This design methodology is briefly introduced and validated. Finally, an application example to an outstanding structure is presented.

Bio : After graduating in Civil Engineering at the Technical Univ. of Lisbon, Portugal, António A. Correia had a challenging experience as a professional engineer in design companies and lecturer at different universities which led him to further specialize in both Structures and Geotechnics. This path eventually resulted in a PhD in Earthquake Engineering on the topic of SSI at the UME School, IUSS Pavia, Italy.
He is currently a Researcher at the Earthquake Engineering and Structural Dynamics Unit of the Portuguese National Laboratory for Civil Engineering (LNEC), where he conducts shake table tests and structural vulnerability and risk studies, alongside a continued activity on the development of advanced numerical models. He also serves as Technical Secretary at Sub-Commission 8 (Eurocode 8) of Technical Committee 250 (Structural Eurocodes) of the European Standardization Committee (CEN/TC250/SC8).
His main expertise research and interests are in the fields of experimental assessment and numerical modelling of the seismic response of structures, as well as on seismic risk, structural vulnerability and design code developments.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
25/02/2016 @ 10:00 room INN 128

Computational Linguistics for Classics

This is an internal talk to which everyone is welcome, on the topic of current computational linguistics research and resources for the domain of Classics, mainly Latin literature. Speakers: Marco Passarotti and Eleonora Litta Picozzi Durban, Catholic University of Milan.
The topics include:
A) Linguistic resources
- Index Thomisticus Treebank Latin Dependency Treebank
- Lexica for Latin
- Morphological Derivational Lexica for Latin
B) NLP tools for Latin
- Morphology: LEMLAT
- PoS tagging, parsers, semantic role labelling
C) Network Analysis for dependency treebanks
D) The Busa Archive

Organized by Digital Humanities Laboratory
26/02/2016 @ 12:15 room GC B3 30

Network Design and Facility Location in Transportation

Prof. Bernard Gendron, University of Montreal, Canada

In this talk, I will give an overview of the applications in transportation of network design and facility location models. In particular, I will present three research projects I am involved in that illustrate typical applications. The first one comes from the forest industry and concerns the location of logging camps for workers. The second one focusses on the location of vehicle inspection facilities, taking into account the allocation of patrols. The third one is a facility location problem for an express package delivery company.

Bio : Bernard Gendron is a Professor at the Département d’informatique et de recherche opérationelle, Université de Montréal. He was the Director of CIRRELT, the Interuniversity Research Centre on Enterprise Networks, Logistics and Transportation (2008-2015). His research interests focus on the optimization of logistics and transportation networks. He has held positions of Principal Scientist at ILOG, Paris, and of Visiting Professor at MIT, EPFL, Pisa, Nice-Sophia-Antipolis, Blaise-Pascal, Versailles and Valenciennes. He has served as Chair of the Canadian Operational Research Society (CORS), Chair of the Montreal Chapter of CORS, and Chair of the Section on Transportation Science & Logistics of INFORMS (the Institute for Operations Research and the Management Sciences). He was awarded the CORS Practice Prize (2004), the CORS Service Award (2006) and the CORS Merit Award (2010).GC

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
04/03/2016 @ 12:15 room GC B3 30

Analysis and design of piled raft foundations allowing for pile-soilraft interaction effects

Prof. Dr Emilios M. Comodromos, University of Thessally, Dept of Civil Engineering, Geotechnical Section, Greece

Although simplified design methods for piled raft foundations have been proposed to allow for group effect and soil-pile-raft interaction, most of them are concentrated on one type of loading rendering the applicability of these methods rather limited to cases under such loads. In the case of a Combined Pile Raft Foundation (CPRF) the structural loads are carried partly by the piles and partly by the raft as a function of the foundation settlement rendering the CPRF a complex soil-structure interaction issue. Despite the recent development of computational resources and the advances in numerical expertise, a detailed 3-D numerical analysis, accounting for soil nonlinearities, non-linear behavior of interfaces between the soil, the piles and the raft under various combinations of loadings remains impractical. The objective of this paper is to provide a rather simplified and straightforward design methodology for pile foundations under combined loadings. To achieve this goal, previous research works on the group effect under axial and lateral loading have been evaluated and the piles-raft interaction effect has been considered. The proposed procedure is fully compatible with structural software codes and can be straightforwardly applied for the design of the structural members, since it is able to effectively solve a CPRF under numerous combinations of loadings required by most design codes.

Bio : Professor Emilios Comodromos is lecturer at the University of Thessally, Dept. of Civil Engineering, Geotechnical Section, Shareholder and Consultant at GEOSTATIKI S.A. Consulting Engineers: Geotechnical and Structural Consultants and Consultant to public company Attiko Metro S.A. for the construction of Thessaloniki’s subway. He graduated at Aristotle University of Thessaloniki in 1986 (top 3 %) and obtained his PhD in Geotechnical Engineering in 1991 awarded by the Aristotle University of Thessaloniki, Greece.
His domains are : Analysis and design of infrastructures involving Geotechnical Engineering and soil-structure interaction projects (tunnels, foundations, retaining structures, rock-fill dams, embankments, slope stability, reinforced embankments etc.), Checker, Reviewer and Consultant in projects mentioned above and Numerical modelling and simulation including 3D non linear multi-stage analysis associated with complex constitutive laws

Organized by Prof. Dr Lyesse Laloui
11/03/2016 @ 12:15 room GC B3 30

A Unified Framework for Evaluating Microscopic Pedestrian Simulation Models

Dr Stefan Seer, Scientist, AIT Austrian Institute of Technology, Vienna, Austria

Microscopic simulation models are used in many applications for predicting pedestrian flows with high granularity. Current simulators do not allow for easy and quick switching between models. Moreover, reliable human movement data is still sparse, which is a prerequisite for model calibration and validation. These shortcomings inhibit to evaluate the capabilities of different models.
This talk presents a unified framework for the structured investigation on strengths and weaknesses of microscopic pedestrian simulation models. The empirical baseline is a highly accurate benchmark data set measured under real life conditions in a bidirectional corridor with a novel data collection approach using the Microsoft Kinect. The proposed simulation framework is built on a scalable and flexible system architecture to easily integrate different models. The results highlight individual capabilities of seven different modeling approaches to represent microscopic and macroscopic characteristics of human movement behavior.

Bio : Dr. Stefan Seer is leading the “Dynamic Crowd Solutions” research group at the AIT Austrian Institute of Technology in Vienna. He was a visiting researcher with the SENSEable City Lab at the Massachusetts Institute of Technology. He is the coordinator of the research collaboration between the AIT and the MIT, where he currently leads a project on “Persuasive Urban Mobility” together with the MIT Media Lab and a project on “Perception Based Modeling” together with the MIT SENSEable City Lab. He was awarded the “National Award for Traffic 2008” by the Austrian Ministry for Transport, Innovation and Technology in the category “Logistic Traffic Solutions at Major Events” for an innovative computer-aided crowd control system to optimize pedestrian flows in public transport infrastructures.
He has specialized for more than 10 years in the development of models and algorithms for pedestrian flow simulation also including technologies to collect and analyze data on crowd behavior in the context of urban transportation. He has a Master's Degree in Electronics Engineering and holds a Doctoral Degree in Computer Science from Vienna University of Technology

Organized by Prof. Dr Michel Bierlaire
18/03/2016 @ 12:15 room GCB330

The mechanics of intermediate and deep focus earthquakes

Prof. Dr Alexandre Schubnel, Associate Researcher at CNRS and Associate Professor at ENS, Paris, France

At least part of the subducting slab seismic activity could be triggered by phase transformations and mineral reactions. However, the way mineral reactions can modify the deformation regime of deep rocks, from ductile to brittle (embrittlement) is still poorly understood and remains one of the outstanding unsolved problems of geophysics and rock mechanics.
Here, we provide experimental evidence that, under differential stress at high pressure and temperature conditions (3-5GPa/800-1000°C), shear fractures nucleate and propagate at the onset of the olivine -> spinel transition in the Mg2GeO4 analogue system. The propagation of these fractures is sufficiently rapid to radiate energy in the form of intense acoustic emissions (AEs). Using a similar set-up, a second set of experiments demonstrates that glaucophane and lawsonite mixtures, two of the principal mineral water carriers in the subducted oceanic crust, undergo dynamic fracture instabilities when deformed within the eclogite field (3GPa/400-800°C). This time, AEs are observed due respectively to the glaucophane breakdown into jadeite and talc under low temperature and lawsonite dehydration under higher temperature. Finally, deformation experiments performed on partially serpentinized peridotites at 2-4 GPa, 500-700°C, demonstrate that 5% serpentine in sufficient to trigger dehydration embrittlement of the peridotite body. In this case, low serpentine contents may favor initiation of mechanical failure of the olivine “load bearing” network.
Put together, our observations provide strong experimental evidence of the role played by mineral reactions on earthquake triggering in mantle conditions, both in the Wadati-Benioff double plane of seismicity and in the Earth mantle's transition zone.
(full abstract as pdf available on memento)

Bio : Alexandre Schubnel has a double appointment:
1) as an associate researcher at the Centre National de la Recherche Scientifique, and
2) as an associate professor at the Laboratoire de Géologie of Ecole Normale Supérieure in Paris, France. His research interests lie in experimental Rock Physics and Earthquake Mechanics. In 2014, Alexandre Schubnel was awarded the bronze medal of CNRS and the Gouilloud-Schlumberger award of the French National Academy of Sciences for his work on “laboratory earthquakes"The mechanics of intermediate and deep focus earthquakes

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
08/04/2016 @ 12:15 room GCB330

Stochastic Seismic Response and Reliability of Reinforced Concrete Structures

School of Civil Engineering & State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, China

Under strong earthquakes the performance and safety of engineering structures are of paramount importance. In this scenario, the structures usually exhibit strong nonlinear behaviors, and simultaneously, there are large degree of randomness in both structural properties and seismic excitations. Such coupling of nonlinearity and randomness in the analysis practical structures of large degrees of freedom leads to great challenges. To this end, in the past over 10 years, we developed a family of probability density evolution method (PDEM), where the principle of preservation of probability is advocated as a basis of stochastic dynamics, and the physical mechanism/physical equations are incorporated into the random event description of this principle, leading to the generalized density evolution equation. In contrast to the traditional equations (e.g., FPK equation), this equation in a one-dimensional equation and therefore could be applied to complex systems. Numerical methods were developed. Further, combined with the stochastic damage constitutive law of concrete, we implemented the stochastic seismic response and reliability evaluation of practical concrete structures. Some engineering applications will be illustrated.

Bio : Jianbing Chen is currently a full professor on the faculty at Tongji University in the School of Civil Engineering. He specializes in the area of earthquake engineering, stochastic dynamics and structural reliability. Specifically, he is working on the development of probability density evolution method (PDEM) for performance evaluation and reliability assessment of structures/engineering systems involving randomness both in the system properties and excitations. Dr. Chen received a Ph.D. in Civil Engineering from Tongji University, China in 2002. He has been a visiting scholar/visiting professor in the University of Southern California in USA (2006-2007), Taiwan University of Science and Technology in China (2011), Aalborg University in Denmark (2012), and Vienne University of Technology in Austria (2014). Dr. Chen is the co-author of an English book titled “Stochastic Dynamics of Structures” (John Wiley & Sons, 2009), the co-author of 3 Chinese books and over 150 technical publications, among which are nearly 110 peer-reviewed journal papers, in the fields of structural stochastic analysis and reliability theory. He was selected into the “NCET Plan” of MOE of China in 2007 and the “Dawn Plan (Shuguang Plan)” of Shanghai Municipal Government in 2011, was the recipient of Huo Ying Dong prize in 2012, and “National Outstanding Scientific and Technological Workers” of China in 2014. He now also serves as a member of the Joint Committee on Structural Safety (JCSS), vice Chairman of the Random Vibration Committee of the Chinese Society of Vibration Engineering (CSVE), Chairman of the Vibration Mechanics Committee of the Shanghai Society of Theoretical and Applied Mechanics (CSTAM), and in the editorial board of “Journal of Vibration Engineering”. He was among the “Most Cited Chinese Researchers” in 2014 and 2015.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
08/04/2016 @ 12:15 room GCB330

Stochastic Seismic Response and Reliability of Reinforced Concrete Structures

Professor Jianbing Chen, School of Civil Engineering & State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, China

Under strong earthquakes the performance and safety of engineering structures are of paramount importance. In this scenario, the structures usually exhibit strong nonlinear behaviors, and simultaneously, there are large degree of randomness in both structural properties and seismic excitations. Such coupling of nonlinearity and randomness in the analysis practical structures of large degrees of freedom leads to great challenges. To this end, in the past over 10 years, we developed a family of probability density evolution method (PDEM), where the principle of preservation of probability is advocated as a basis of stochastic dynamics, and the physical mechanism/physical equations are incorporated into the random event description of this principle, leading to the generalized density evolution equation. In contrast to the traditional equations (e.g., FPK equation), this equation in a one-dimensional equation and therefore could be applied to complex systems. Numerical methods were developed. Further, combined with the stochastic damage constitutive law of concrete, we implemented the stochastic seismic response and reliability evaluation of practical concrete structures. Some engineering applications will be illustrated.

Bio :
Jianbing Chen is currently a full professor on the faculty at Tongji University in the School of Civil Engineering. He specializes in the area of earthquake engineering, stochastic dynamics and structural reliability. Specifically, he is working on the development of probability density evolution method (PDEM) for performance evaluation and reliability assessment of structures/engineering systems involving randomness both in the system properties and excitations. Dr. Chen received a Ph.D. in Civil Engineering from Tongji University, China in 2002. He has been a visiting scholar/visiting professor in the University of Southern California in USA (2006-2007), Taiwan University of Science and Technology in China (2011), Aalborg University in Denmark (2012), and Vienne University of Technology in Austria (2014). Dr. Chen is the co-author of an English book titled “Stochastic Dynamics of Structures” (John Wiley & Sons, 2009), the co-author of 3 Chinese books and over 150 technical publications, among which are nearly 110 peer-reviewed journal papers, in the fields of structural stochastic analysis and reliability theory. He was selected into the “NCET Plan” of MOE of China in 2007 and the “Dawn Plan (Shuguang Plan)” of Shanghai Municipal Government in 2011, was the recipient of Huo Ying Dong prize in 2012, and “National Outstanding Scientific and Technological Workers” of China in 2014. He now also serves as a member of the Joint Committee on Structural Safety (JCSS), vice Chairman of the Random Vibration Committee of the Chinese Society of Vibration Engineering (CSVE), Chairman of the Vibration Mechanics Committee of the Shanghai Society of Theoretical and Applied Mechanics (CSTAM), and in the editorial board of “Journal of Vibration Engineering”. He was among the “Most Cited Chinese Researchers” in 2014 and 2015.

Organized by Prof. Dr Katrin Beyer & Prof. Dr Brice Lecampion
15/04/2016 @ 12:15 room GCB330

W–SPSA in practice: Approximation of weight matrices and calibration of traffic simulation models

Prof. Dr Constantinos Antoniou, National Technical University of Athens, Greece

The development and calibration of complex traffic models demands parsimonious techniques, because such models often involve hundreds of thousands of unknown parameters. The Weighted Simultaneous Perturbation Stochastic Approximation (W–SPSA) algorithm has been proven more efficient than its predecessor SPSA, particularly in situations where the correlation structure of the variables is not homogeneous. This is crucial in traffic simulation models where effectively some variables (e.g. readings from certain sensors) are strongly correlated, both in time and space, with some other variables (e.g. certain OD flows). In situations with reasonably sized traffic networks, the difference is relevant considering computational constraints. However, W–SPSA relies on determining a proper weight matrix (W) that represents those correlations, and such a process has been so far an open problem, and only heuristic approaches to obtain it have been considered.
In this seminar, W–SPSA is presented in a formally comprehensive way, where effectively SPSA becomes an instance of W–SPSA, and explores alternative approaches for determining the matrix W. It is demonstrated that, relying on a few simplifications that marginally affect the final solution, W matrices that considerably outperform SPSA can be obtained. The performance of the proposed algorithm is presented in two applications in motorway networks in Singapore and Portugal, using a dynamic traffic assignment model and a microscopic traffic simulator, respectively.

Bio : Constantinos Antoniou is Associate Professor in the National Technical University of Athens (NTUA), Greece, and a Research Affiliate at MIT. He holds a Diploma in Civil Engineering from NTUA (1995), a MS in Transportation (1997) and a PhD in Transportation Systems (2004), both from MIT. His research focuses on modelling and simulation of transportation systems, Intelligent Transport Systems (ITS), calibration and optimization applications, road safety and sustainable transport systems and in his 20 years of experience he has been involved in a large number of projects, primarily in Europe, the US and Asia.
For more information please see http://users.ntua.gr/antoniou

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
22/04/2016 @ 12:15 room GCB330

Compressive behaviour of long-fibre composites: a multi-scale approach

Prof. Dr Olivier Allix, LMT-Cachan / Institut Universitaire de France

The intensive use of Carbon Fibres Reinforced Plastics in aeronautics implies to master the prediction of the behaviour of composite up to final failure and if one consider energy absorption even further. The so-called virtual testing approach supports this goal and relies on the use of robust models keeping the key physical mechanisms into account.
An important aspect of the response of composite is compression, which involve a particular mode of deterioration the kinking of fibres. In dynamics it can lead to a large amount of dissipated energy thanks to the fragmentation of the whole structure. Thanks to many works the physics of formation of kinking is today relatively well understood at the scale of the fibres, the one of the energy dissipated in the process far less. Moreover, its modelling at the meso-scale and its interaction with delamination is still a challenging issue.
Preliminary studies focus on quasi-static loadings of small samples. A micro model of a representative unit cell incorporating carbon fibres in an epoxy matrix has been developed to account for the main degradation mechanisms associated to kinking. It is based on Fleck & Budiansky’s kinking theory [1]. This micro model has been used to extract the most important characteristics (strength, dissipated energy, kink band size) [2-3] and the associated scattering mainly due to the statistical waviness of the fibres. From that point on, a ply-scale model has been improved to account for compressive loadings [4]. The chosen representative volume element relies on the fragment size at the micro scale. An approximate potential form has been proposed and the associated state and evolution laws are identified using an energy equivalence principle between the scales – and models. The kink band size plays the role of a localization limiter. This constitutive law is parameterized by the fibre waviness angle and is able to represent material and geometrical nonlinearities under multi-axial loadings.
This work can be divided in three parts. The first one describes the kinking micro model and the main associated results. The second part focuses on the construction of a homogenized constitutive law at the meso-scale. The third part features an application of the strategy to the modelling of the degradation of holed plates in compression. For this purpose, the meso-scale model has been implemented in the virtual material model proposed in [5]. This hybrid description strategy allows the interaction between the micro buckling mechanism (kinking) and other classical degradation mechanisms, such as delamination and transverse cracking [6], to take place for any configuration. The discussion of the relevance of the approach using qualitative comparisons between simulation [7] and experiments from the literature [8-9] will be discussed.

[1] B. Budiansky and N. A. Fleck, N. Compressive failure of fibre composites. Journal of the Mechanics and Physics of Solids, 41(1):183-211, 1993.
[2] J.M. Guimard, O. Allix, N. Pechnik, and P. Thévenet. Energetic analysis of fragmentation mechanisms and dynamic delamination modelling in {CFRP} composites. Computers and Structures, 87(15):1022-1032, 2009.
[3] N. Feld, O. Allix, E. Baranger, and J.M. Guimard. Micro-mechanical prediction of UD laminates behavior under combined compression up to failure: influence of matrix degradation. Journal of Composite Materials, 45(22):2317-2333, 2011.
[4] N. Feld, O. Allix, E. Baranger, and J. M. Guimard. A micromechanics-based mesomodel for unidirectional laminates in compression up to failure. Journal of Composite Materials, 46(23):2893-2909, 2012.
[5] P. Ladevèze, G. Lubineau, and D. Violeau. A computational damage micromodel of laminated composites. International Journal of Fracture, 137(1):139-150, 2006.
[6] C. S. Yerramalli and A. M. Waas. A failure criterion for fiber reinforced polymer composites under combined compression-torsion loading. International journal of solids and structures, 40(5):1139-1164, 2003.
[7] Allix, O., Feld, N., Baranger, E., Guimard, J.M., Ha-Minh, C. The compressive behaviour of composites including fiber kinking: modelling across the scales. Meccanica. Vol 49. Num 11. Pages 2571-2586. 2014
[8] Soutis C, Fleck NA (1990) Static compression failyre of 943 carbon fibre T800/924C composite plate with a single hole. 944, J Compos Mater 24:536–558
[9] Lee J, Soutis C (2008) Measuring the notched compressive strength of composite laminates: specimen size effects. Compos Sci Technol 68:2359–2366

Bio : Olivier Allix is Professor (of Exceptional class) at the Ecole Normale Supérieure de Cachan and previous director of LMT-Cachan and is member of the prestigious Institut Universitaire de France. Olivier Allix has worked intensively in connection with Airbus and other companies on the modelling of the mechanical behaviour of composites and the developement of multiscale strategies to deal with those complex material and structures. He recently proposed non intrusive computational methods to easily implemnt those techniques into commercial packages. Olivier Allix serves as member of 12 editorial boards of international journals. He organized the Fourth European Conference on Computational Mechanics in Paris in 2010 with more than 2000 participants and is an Euromech and IACM fellow.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
28/04/2016 @ 12:15 room GC B3 30

The Inequality Level Set, a novel approach to handle variational inequalities : application to contact

Prof. Dr Nicolas Moës, Ecole Centrale de Nantes, France & researcher at GeM (Research Institute for Civil and Mechanical Engineering)

The key idea of the ILS for variational inequalities is to try to locate with a level set the domain over which the inequality reaches an equality. For contact problem, it means that the main unknownis the contact zone. This is an important departure from classical contact algorithm since at any iteration an explicit contact contour is known as a level set. A true Newton-Raphson may thus be built with respect to the contact location. The derivative of the energy with respect to the contact zone location has the meaning of a configurational force. For frictionless contact it must be driven to zero to reach the exact contact zone, whereas in case of adhesion the force must correspond to the adhesion level.

The two main advantages of the ILS are : possibility to enrich with the XFEM the contact zone boundary to capture non-smoothness of the displacement field (higher order order of convergence contact is thus at hand) and robustness in the iterative process since it is based on a full Newton-Raphson.
Examples of simulation of contact of membranes or deformable bodies on a rigid obstacle will show the capabilities of the ILS.

Nicolas Moës, Nicolas Chevaugeon and Matthieu Graveleau, Ecole Centrale de Nantes, UMR CNRS, Nantes, France

References
Bonfils, N., Chevaugeon, N., & Moës, N. (2012). Treating volumetric inequality constraint in a continuum media with a coupled X-FEM/level-set strategy. Computer Methods in Applied Mechanics and Engineering, 205-208, 16–28. doi:10.1016/j.cma.2011.02.012

Graveleau, M., Chevaugeon, N., & Moës, N. (2015). The Inequality level-set approach to handle
contact: membrane case. Advanced Modeling and Simulation in Engineering Sciences, 2:16.

Bio : Nicolas Moës is full Professor at the Ecole Centrale de Nantes (France) since 2001 and researcher at the GeM (research institute for civil and mechanical engineering).
He recieved his phd in 1996 from Ecole Normale Supérieure de Cachan after which he did spend 5 years in the USA under the supervizion of Professors Oden and Belytschko. He is one of the co-inventor of the eXtended Finite Element Method (X-FEM) for fracture mechanics and for other applications like material interfaces.
His current areas of interest are damage to fracture transition and contact algorithms. He received the young investigator award from the IACM (International Association for computational Mechanics) in 2006 and was declared IACM fellow in 2008. In 2014, he received the silver medal from CNRS.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
29/04/2016 @ 12:15 room GCB330

Suspensions of particles and bubbles in yield stress fluids

Dr Guillaume Ovarlez, Senior Research Scientist at LOF-CNRS-Solvay-University of Bordeaux, France

Many dense suspensions involved in industrial processes (concrete casting, drilling muds, foodstuff transport, etc.) and natural phenomena (debris-flows, lava flows, etc.) are yield stress fluids which contain a significant fraction of coarse rigid particles. In addition, some of these materials contain air bubbles: crystal bearing magmas, aerated food emulsions, foamed plaster slurries… When scale separation between the paste microstructure (the colloidal particle size) and the noncolloidal particles or bubbles in suspension is possible, a simplification occurs: these materials can be considered as noncolloidal particles or bubbles embedded in a yield stress fluid (the colloidal paste). From a fundamental point of view, one then deals with suspensions in which particles interact through nonlinear hydrodynamical interactions.
In this talk, we will present recent advances in the characterization and understanding of the behavior of suspensions of rigid and soft inclusions in yield stress fluids.
We will first show how model materials and appropriate procedures are designed to focus on the purely mechanical contribution of the particles/bubbles to the yield stress fluid behavior, independently of the physicochemical properties of the materials. This allows an in depth comparison with micromechanical estimates. We will then focus on the impact of particles on the linear and nonlinear rheological properties (elastic modulus, yield stress, consistency) of the fluid. The variations of these properties with the particle volume fraction are found to be in good agreement with those predicted by a micromechanical approach in which the concentration of shear between the inclusions is taken into account. In the case of suspensions of bubbles, bubbles can behave as rigid or soft particles, dependant on their physical properties and on the interstitial fluid mechanical properties; we will show that the visco-elastic and visco-plastic behaviors of these materials are governed by two different dimensionless capillary numbers, which gives rise to original properties.
We will finally briefly discuss shear-induced migration and shear-induced sedimentation issues. These phenomena can be quantitatively modeled when the 3D behavior of the interstitial yield stress fluid and the local properties of shear between the particles are taken into account.
References:
1. F. Mahaut, X. Chateau, P. Coussot, G. Ovarlez, Yield stress and elastic modulus of suspensions of noncolloidal particles in yield stress fluids, Journal of Rheology 52, 287-313 (2008).
2. X. Chateau, G Ovarlez, K. Luu Trung, Homogenization approach to the behavior of suspensions of noncolloidal particles in yield stress fluids, Journal of Rheology 52, 489-506 (2008).
3. T.-S. Vu, G. Ovarlez, X. Chateau, Macroscopic behavior of bidisperse suspensions of noncolloidal particles in yield stress fluids, Journal of Rheology 54, 815-833 (2010).
4. G. Ovarlez, F. Bertrand, P. Coussot, X. Chateau, Shear-induced sedimentation in yield stress fluids, Journal of Non-Newtonian Fluid Mechanics 42, 148-157 (2012).
5. L. Ducloué, O. Pitois, J. Goyon, X. Chateau, G. Ovarlez, Coupling of elasticity to capillarity in soft aerated materials, Soft Matter 10, 5093-5098 (2014).
6. L. Ducloué, O. Pitois, J. Goyon, X. Chateau, G. Ovarlez, Rheological behaviour of suspensions of bubbles in yield stress fluids, Journal of Non-Newtonian Fluid Mechanics 215, 31-39 (2015).
7. G. Ovarlez, F. Mahaut, S. Deboeuf, N. Lenoir, S. Hormozi, X. Chateau, Flows of suspensions of particles in yield stress fluids, Journal of Rheology (2015).

Bio :
Dr Guillaume Ovarlez is senior research scientist (Directeur de Recherche) at CNRS Laboratory Of the Future in Bordeaux, France since 2014. He previously was a CNRS senior researcher at Laboratoire Navier, Ecole des Ponts since 2003. He holds a PhD in Physics from University Paris XI and an engineering degree from Ecole Polytechnique, France. Dr Ovarlez has notably received the Bronze Medal of CNRS in 2009, and the prix “de la Recherche” in 2007 for his work on rheology of complex suspensions.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
13/05/2016 @ 12:15 room GC B3 30

Response or Reinforced-Concrete Buildings to the Taiwan Earthquake of February 5, 2016

Dr Santiago Pujol, Professor of Civil Engineering, Purdue University, West Lafayette, IN, USA

Abstract :
The magnitude-6.4 Southern Taiwan earthquake occurred near the city of Tainan, Taiwan, on February 5, 2016, causing severe damage, partial collapse, and full collapse of low-to-midrise reinforced concrete buildings. While initial measures of ground motion intensity indicated potential for moderate structural damage, ten reinforced concrete buildings collapsed and hundreds more were reported to have severe damage as a consequence of the earthquake. This damage was surprising because Taiwan has made considerable investments into earthquake research, regulations, enforcement, and strengthening. To understand this discrepancy between expected and observed building performance, a team of researchers from the United States traveled to Taiwan to work with Taiwanese researchers. Together they gathered detailed building response data, including the observed damage and properties of building structures in quantifiable terms. Both damaged and undamaged buildings were surveyed to produce a comprehensive data set that can be used to test hypotheses on causes of damage. This presentation describes the data, how to access them, and how they can be used to:
(1) understand causes of building collapse,
(2) identify building properties that increase probability of structural damage,
(3) identify vulnerable structures in seismic areas, in particular among older structures built prior to modern seismic design codes, and
(4) study the relationship between site response and building damage.

Bio :
Santiago Pujol is a Professor of Civil Engineering at Purdue University’s Lyles School of Civil Engineering. A Fellow of the American Concrete Institute (ACI), Santiago is a member of ACI Committees 133, 314, 318R, and 445. He has received the Walter L. Huber Civil Engineering Research Prize from the American Society of Civil Engineers and the Chester Paul Siess Award for Excellence in Structural Research from ACI. Santiago has conducted quantitative earthquake reconnaissance work in Turkey, Colombia, Mexico, Peru, Chile, Japan, China, Haiti, Nepal, and Taiwan

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
20/05/2016 @ 12:15 room GC B3 30

Managing induced seismicity in GeoEnergy applications: Status and outlook

Prof. Dr. Stefan Wiemer, Swiss Seismological Service, ETH Zurich, Switzerland

Induced seismicity is posing an increasing challenge to GeoEnergy applications around the globe, with a substantial economical and societal impact. While in some applications, induced earthquakes are a nuisance and potential seismic risk, in others they are actually a much needed tool to create and optimize underground reservoirs. The art of balancing economic output, seismic safety and societal acceptance requires more advanced tools for monitoring and modeling than available today. In this presentation, I will summarize the major challenges we are facing, and report on the research and development efforts ongoing at SED and ETH to improve our understanding of earthquake processes, and of the ability to reliably forecast induced seismicity. Finally, I will discuss implications for future GeoEnergy projects in Switzerland.

Bio : Prof. Dr. Stefan Wiemer is the chair of seismology at the department of Earth Science, ETH Zurich, and the director of the Swiss Seismological Service (SED, www.seismo.ethz.ch). Born in 1967 in Germany, he graduated from the Ruhr University in Bochum in 1992 and earned his PhD in geophysics from the University of Alaska in Fairbanks in 1996. In 1997, he was awarded a fellowship by the German Alexander von Humboldt Foundation and moved to Tsukuba, Japan. In 1999, he moved to the SED as a research associate, where he initiated and led research groups on statistical seismology and induced seismicity. He was promoted to titular professor in 2007 and appointed as a full professor and SED director in 2013. His expertise and research interests include probabilistic seismic hazard and risk assessment, time-dependent processes, earthquake predictability and operational earthquake forecasting, earthquake early warning and induced seismicity related to GeoEnergy applications.

Organized by Prof. Dr Brice Lecampion
27/05/2016 @ 12:15 room GCB330

Bedload and morphodynamics

Dr Alain Recking, Researcher at Irstea, Grenoble, France

Bedload conditions the development of river morphology along different space and time scales; however, by concentrating the flow in preferential paths, a given morphology controls bedload for a given discharge. As bedload is a non-linear response of shear stress, local morphology is likely to have a strong impact on bedload prediction when the shear stress is averaged over the section, as is usually done. We will see how taking into account the river morphology can help to improve bedload prediction. But on the other hand, predicting the morphology also requires predicting the size of the transported material, and from this point of view, we will discuss the limitation of available computational methods in a morphodynamics perspective.

Bio :
Alain Recking is researcher in the Torrent Erosion and Snow Avalanches group at Irstea, in Grenoble. His research focuses on fluvial-hydraulic processes in gravel- and cobble-bed channels, including grain sorting and feedbacks between flow hydraulics, sediment transport, and morphodynamics. He teaches every years Hydraulic and Sediment Transport in several Universities as well as for staffs of several government agencies.

Organized by Prof. Dr Brice Lecampion & Katrin Beyer
08/06/2016 @ 12:15 room GCC330

Long Span Bridges on Urban Area and Typical Damages due to Major Earthquakes

Prof. Ayaho Miyamoto, Professor Emeritus of Yamaguchi University, Japan

Bridge is a key structure on the road and train networks. There are many bridge types such as beam (girder), arch, truss, suspension and cable stayed. The most important issues on bridge design and construction are “load carrying capacity”, “durability(long life)” and “sustainability (environmental friendly)”. In Japan, we have constructed more than 700,000 existing bridges which are not only long span bridges but also short and medium span bridges. Many of them are constructed in urban area including coastal area, such as Tokyo, Osaka, Kobe, etc. In this lecture, I will introduce mainly not only how to design a beautiful and strong long span bridges in a urban coastal area but also what kind of construction procedures was applied actually to them in the bridge site.
On the other hand, because the urban areas are generally in a high possibility area both of the big earthquake and strong typhoon, we need to consider both natural disasters in design process of the long span bridges. Especially, the 1995 Kobe Great Earthquake was a typical “inland earthquake” with the impulsive vertical motion at the early stage of the earthquake. Then, some special damage modes were observed in some parts, such as column-cap beam connection, column-footing connection, etc. in the bridge system. This fact suggests that such impulsive vertical motion in the earthquake possibly induced the circumferential crack of RC piers and also induces serious damages in the bridge piers, bearings, etc.
In this lecture also will be focused into what kinds of typical damage modes under major earthquake were occurred in some parts of long span bridge systems, how to affect the impulsive vertical ground motion on the failure mechanism of them and how to establish an optimal seismic retrofit design in the future from various points of view.

Bio : His recent research activities are in the area of structural safety assessment on concrete bridges including bridge management system(BMS), and also establishment of optimal design concept for concrete structures under soft impact loads.

• 1975 - 1988: Research Associate at Kobe Univ., Japan.
• 1985: Received Dr. of Eng. degree from Kyoto Univ., Japan.
• 1988 - 1995: Associate Professor at Kobe Univ., Japan.
• 1995 - 2015: Professor at Yamaguchi Univ., Japan.
• 2015.4 - now: Professor Emeritus of Yamaguchi Univ., Japan.
• 2015.9-2016.3: Visiting Professor of Aalto Univ., Espoo, Finland.
• 2016.4-2016.9: Visiting Professor of EPFL, Lausanne.
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• 2001.3-:Director, The Practical Maintenance Engineering Institute, Yamaguchi Univ.
• 2008.1-:Director, The Research Center for Environmental Safety, Yamaguchi Univ.
• Japan Society of Civil Engineers(JSCE) member(Fellow).
• Japan Concrete Institute(JCI) member.
• Japan Society for Fuzzy Theory and Systems(SOFT) member.
• American Society of Civil Engineers(ASCE) member.
• American Concrete Institute(ACI) member.
• International Association for Bridge and Structural Engineering(IABSE) Fellow member.
• International Association for Bridge Maintenance and Safety(IABMAS) member

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
23/09/2016 @ 12:15 room GC A3 31

Role of Nonlinear Analysis and Damage Mechanics in the Seismic Design of Steel Structures

Prof. Dr Amit Kanvinde, University of California-Davis, USA

Finite Element (FE) simulation, in conjunction with nonlinear structural analysis is increasingly used by structural engineers to characterize the performance of structural components and systems. However, interpreting the results (i.e., limiting values of stress and strain demands) of these FE simulations is not straightforward, especially when they are used to assess fracture safety. This is even more challenging for seismic design of structures where traditional fracture mechanics is unreliable where components are designed to undergo large-scale yielding. The talk will summarize recent developments in applications of nonlinear analysis to seismic design and research on continuum-based fracture mechanics, which can reliably assess fracture under these conditions. Applications of these approaches to recent engineering applications and research projects will be presented, along with a discussion of their limitations.

Bio : Amit Kanvinde is interested in the seismic response and design of steel structures, with an emphasis understanding and simulating extreme limit states, such as fracture, fatigue, and collapse. His research combines large and small-scale experiments with model-based simulation to develop a more fundamental understanding of the response of structural systems. Professor Kanvinde is the recipient of the 2008 Norman Medal, and the 2016 Walter Huber Research Prize presented by the American Society of Civil Engineers. He is currently Professor and Chair at the Department of Civil and Environmental Engineering, at the University of California, Davis.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
30/09/2016 @ 12:15 room GCA331

Durability of NSM FRP systems

José Sena Cruz, Associate Professor, University of Minho (UMinho), Portugal

In early 2000s the Near Surface Mounted (NSM) strengthening technique was proposed and used as an alternative system to the externally bonded reinforcement (EBR). In the NSM technique the fibre reinforced polymer (FRP) reinforcements are inserted into pre-cut grooves opened in the concrete cover. Typically epoxy adhesives are used to fix the FRP to concrete. This strengthening technique has prevailed and, when compared with the EBR, presents the many advantages well-reported in the literature. Up to now, the developed research was mostly dedicated to the short-term structural performance of strengthened structural elements and rarely considered the full structure’s life time. The assessment of the full structure’s life time requires the evaluation of the durability of both the strengthening system and the involved materials. The present seminar will introduce the latest developments by the University of Minho on durability of NSM FRP systems. Bio: José Sena Cruz is currently Associate Professor at the Department of Civil Engineering, at the University of Minho (UMinho), Assistant Director of ISISE - Institute in Sustainability and Innovation in Structural Engineering and of LEST – Structural Laboratory of UMinho. He has been specialized in the fields of finite element analysis, computational mechanics, FRP materials, inspection, diagnosis and repairing and strengthening RC structures with FRP materials, testing and constitutive laws, monitoring, and durability and time-depend behaviour of FRP materials used in existing and new structures. He is the author of more than 240 publications, co-founded of FEMIX FEM-based computer program for advanced structural analysis, coordinator of 9 R&D Projects and 17 R&D Projects as a team member, supervisor of 10 PhD theses and editor of Nacional Journal and member of editorial board of 2 International Journals. He is secretary of the RILEM TC 234-DUC, co-chair of WG4 of COST Action TU1207, member of fib – TG 5.1 and TG 8.1, CT115 – Working group of GT4/FRP and Eurocode 2 and national expert of CEN/TC 250/WG 04. He is consultant on the areas of the structural analysis and structural rehabilitation with several consulting works performed.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
07/10/2016 @ 12:15 room GCA331

Compaction localization in geomaterials

Prof. Dr Patrick Baud, Laboratoire de Geophysique expérimentale, Ecole et Observatoire des Sciences de la Terre (EOST), Strasbourg, France

The development of deformation bands has primary importance on fluid flow in subsurface geologic reservoirs and aquifers. Among diversity of compactant failure modes in porous rock, compaction bands are a type of deformation band characterized by a reduction in porosity and permeability across the thin band structure. Mechanical data and microstructural observations on sandstone demonstrate that compaction bands can develop in compositionally heterogeneous rock and are the dominant failure mode in the transitional regime from brittle faulting to cataclastic flow. Recent results reveal that grain size distribution plays a fundamental role in compaction band formation in this rock type. In the most homogeneous sandstones, tabular continuous bands can efficiently impact fluid flow whereas local heterogeneities make the bands more tortuous, less continuous, and in turn less efficient as permeability barrier. The stress states for compaction band formation inferred in the field are significantly lower than those measured in the laboratory data. We however show that compaction bands can develop under creep (constant stress) conditions over extended periods of time, at stresses significantly lower than reported in previous studies and hence closer to estimates based on field observations. Our creep data show that significant time-dependent compaction can be expected in sandstone at stress conditions beyond the yield point. The three damage proxies recorded during our triaxial experiments show an obvious correlation, suggesting that the mechanism leading to this time-dependent compaction is stress corrosion cracking.
While convincing field observations of compaction bands were presented in carbonate formations, experimental studies gave so far contrasted results, suggesting that conditions for compaction band development in limestone may be different than in sandstone. It has been noted that local heterogeneities, material properties and geometric effects may favour or inhibit the formation of compaction bands in porous carbonates. Our recent results based on X-ray computed microtomography suggest that the degree of cementation plays a fundamental role on the development of compaction localization in carbonate formations.
Bio : Parick Baud is currently Professor of Geophysics at EOST Strasbourg. He is in charge of the Rock Physics, Petrophysics, Hydrology, borehole Geophysics and Fracture & Fluid Mechanics courses. In 2008 he was invited professor at COPPE/Universitade Federal of Rio de Janeiro. He got his PhD in 1995 for his thesis : "Theoretical and experimental study of crustal rock fracturing". His current researches are Rock Mechanics and Rock Physics with focus on energy resources, environmental applications and natural hazards. Study of both the phenomenological and micromechanical aspects of rock deformation and fluid flow, using an approach integrating high-pressure experiment, characterization of microstructure and theoretical analysis.
Recent topics: Compaction bands in porous sandstone, time-dependent deformation in rocks, p hysical properties and damage in volcanic rocks: implications for the dynamics on active volcanoes, dilatancy, compaction, failure and fluid flow in carbonate rocks X-ray Computed Microtomography.
63 papers, h index 26(SCOPUS)
RECENT PUBLICATIONS
Zhu, W., P. Baud, S. Vinciguerra, and T.-f. Wong, Micromechanics of brittle faulting and cataclastic flow in Mount Etna basalt, J. Geophys. Res. Solid Earth, 121, doi:10.1002/2016JB012826, 2016.
Baud, P., T. Reuschlé, Y. Ji, C. Cheung, and T.-f. Wong, Mechanical compaction and strain localization in Bleurswiller sandstone, J. Geophys. Res. Solid Earth, 120, doi:10.1002/2015JB012192, 2015.
Heap M.J., N. Brantut, P. Baud, and P.G. Meredith, Time-dependent compaction band formation in sandstone. J. Geophys. Res., DOI: 10.1002/2015JB012022, 2015.
Ji, Y., S. Hall, P. Baud, and T.-f. Wong, Characterization of pore structure and strain localization in Majella limestone by X-ray computed tomography and digital image correlation, Geophys. J. Int., 200, 701-719, 2015.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
14/10/2016 @ 12:15 room GCA331

Data analytics and simulation tools for urban mobility of the future

Prof. Dr Justin Dauwels, Associate Professor, School of Electrical and Electronic Engineering, Nanyang Technological University (NTU) Singapore

An estimated 64% of all travel today is made within urban environments. By 2050 the total amount of urban kilometres travelled worldwide is expected to triple, with traffic congestion potentially bringing major cities to a standstill. In Singapore, a small island with a population of 5.4 million, there are approximately 1 million cars on the roads. At the same time, roads take up 12% of land space. With the limited land space in Singapore, it is unrealistic to further increase the number of vehicles or add more roads. To address these challenges, the Singapore government plans to implement an intelligent and adaptable transport system which uses data to empower commuters and adjusts to their needs. Sensor networks are being deployed that collect data from busy areas such as traffic junctions, bus stops and taxi queues, then relay it back to the relevant agencies for analysis through data analytics and real-world applications. Besides transportation systems powered by big data analytics, driverless vehicles are also a major focus so far for the Singapore government. More than six kilometres of public roads have been opened this year for AV trials, currently in use for trials with a small fleet of public self-driving taxis. Various stakeholders are aiming for full-scale commercial autonomous taxi service in 2018 in Singapore.

It is within this context that our research group has developed various data analytics and simulation tools for transportation applications. In the seminar, I will give an overview of our research efforts.
Over the last years, we have been working towards scalable real-time algorithms for predicting traffic speed and travel time. The prediction systems designed by our team is able to perform accurate real-time predictions in large networks consisting of 10,000 – 100,000 links, by exploiting the correlations in traffic data. The sensing and prediction can be performed in a distributed fashion, e.g., on smartphones, as alternative to high-cost centralized systems. In recent work, we are investigating the effect of rainfall and road incidents on road traffic, in an attempt to further improve traffic predictions by incorporating information about traffic incidents and weather. We are also working towards traffic-and weather-aware online stochastic routing algorithms that are able to adapt the routes of vehicles based on real-time information about the condition of the transportation networks.
Besides macro-scale data analytics, our team is designing machine learning algorithms for micro-scale transportation applications. Specifically, currently we are creating algorithms for scene understanding in urban and off-road scenarios. In collaboration with our local industry partner ST Engineering, we are integrating these technologies into autonomous vehicles (AVs) for urban mobility and airport automation.
In parallel efforts, we have created a simulation platform for exploring emerging transportation paradigms. One of these technologies is vehicle-to-vehicle (V2V) and vehicle-to-infrastructure communications systems (V2X). Our simulation platform allows researchers to explore various use cases of V2V/V2X technologies at a high level of realism, including smart traffic signals and vehicle platooning. As part of the recently established Centre of Excellence for Testing and Research of Autonomous Vehicles - NTU (CENTRAN), the team is currently incorporating realistic models of AVs into the simulation platform, which will yield a sophisticated simulation tool for studying and testing AVs and designing the required infrastructure for supporting AVs. This simulation tool will be instrumental for the certification of AVs to be deployed in Singapore. The tool will also allow us to simulate and design various approaches to collect, communicate, and analyse transportation data through networks of V2V/V2X enabled AVs, providing real-time macro-scale analytics about transportation networks.
Bio : Dr. Justin Dauwels is an Associate Professor with School of Electrical and Electronic Engineering at the Nanyang Technological University (NTU) in Singapore. He serves as Deputy Director of the ST Engineering – NTU corporate lab, which comprises 100+ PhD students, research staff and engineers, developing novel autonomous systems for airport operations and transportation. He is also involved as project PI in the Centre of Excellence for Testing and Research of Autonomous Vehicles - NTU (CENTRAN), which will lead the development of testing requirements for such vehicles, and was launched by the Land Transport Authority (LTA) and JTC, in partnership with NTU. Moreover, he serves as project PI in the BMW-NTU lab on Future Mobility,
and the NXP-NTU lab on vehicle-to-vehicle communications.
His research interests are in data analytics with applications to intelligent transportation systems, autonomous systems, and analysis of human behavior & physiology. He obtained the PhD degree in electrical engineering at the Swiss Polytechnical Institute of Technology (ETH) in Zurich in December 2005. He was a postdoctoral fellow at the RIKEN Brain Science Institute (2006-2007) and a research scientist at the Massachusetts Institute of Technology (2008-2010). He has been a JSPS postdoctoral fellow (2007), a BAEF fellow (2008), a Henri-Benedictus Fellow of the King Baudouin Foundation (2008), and a JSPS invited fellow (2010, 2011). His research on intelligent transportation systems has been featured by the BBC, Straits Times, Lianhe Zaobao, Channel 5, and numerous technology websites. His research team has won several best paper awards at international conferences. Besides his academic efforts, the team of Dr. Justin Dauwels also collaborates intensely with local start-ups, SMEs, and agencies, in addition to MNCs, in the field of data-driven transportation and logistics.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
21/10/2016 @ 12:15 room GCA331

Advanced numerical analysis as a tool for the research and design of unconventional steel structures

Prof. Dr Charis J. Gantes, Institute of Steel Structures – School of Civil Engineering – National Technical University of Athens, Greece

Abstract : Numerical calculation of the ultimate strength of unconventional steel structures by means of the nonlinear finite element method will be presented. In modern codes checks in the ultimate limit state are commonly carried out by comparing action effects obtained from linear elastic analyses with corresponding resistances given from formulas that account indirectly for geometric and material nonlinearity as well as imperfections. Thus, prediction of collapse, which is a strongly nonlinear phenomenon, is possible by performing linear analyses, using simple software that is readily available and sufficiently reliable for ordinary structural systems. Alternatively, prediction of ultimate strength via nonlinear numerical analyses is also permitted by modern codes. This method is recommended for complex structural systems or members with unusual shapes and irregular cross-sections, as such cases are not covered by available buckling curves and interaction equations. This can only be accomplished successfully if engineers posses the necessary theoretical background, so that that they can set-up realistic numerical models, select appropriate solution algorithms and parameters and are able to interpret correctly the results.
Along these lines, in the first part of the present lecture fundamental concepts of nonlinear structural behavior will be briefly reviewed. Numerical tools for understanding the behavior, predicting all possible failure modes and evaluating the ultimate capacity of steel structures using commercially available software will then be presented. Failure dominated by either material yielding or instability will be addressed, as well as interaction of failure modes. Steps of the proposed methodology include setting up an appropriate finite element model, obtaining critical buckling modes from linearized buckling analysis (LBA), and then using a linear combination of these modes as imperfection pattern for a geometrically and material nonlinear imperfection analysis (GMNIA). Equilibrium paths accompanied by snapshots of deformation and stress distribution at characteristic points will be highlighted as a powerful tool for evaluating the results of the GMNI analysis, identifying the dominant failure modes and thus proposing appropriate strengthening measures, if needed.
In the second part of the presentation applications of this approach in research activities will be described, including (i) strengthening of the manhole at the base of wind turbine towers to avoid local buckling, (ii) formulating design rules for laced and battened built-up members used in long-span and/or large height steel hangars and bridges, (iii) studying the buckling behavior of large-diameter industrial steel chimneys.
In the third and final part applications of the above approach in actual engineering projects will be briefly mentioned, including (i) the suspended roof covering the archaeological site of Aristotle’s Lyceum in Athens, (ii) the evaluation of consequences of potential landslides and fault activation on the buried pipeline Kipoi-Alexandroupolis-Komotini, (iii) the steel structures providing temporary support for the deep excavations of Thessaloniki Metro, (iv) the steel structures supporting the cladding of Oval Tower in Limassol.
Bio :
Prof. Charis Gantes, born in Athens, Greece, in 1962, attended the German High school of Athens (Dörpfeld Gymnasium), and then obtained a Civil Engineering Diploma from the National Technical University of Athens (NTUA) in 1985, and a Master’s (1988) and Ph.D. (1991) from the Massachusetts Institute of Technology (MIT). Since 1994 he is faculty member in the Institute of Steel Structures at NTUA, where he is teaching steel structures, structural stability and tension structures.
His current research activity is in the area of structural behavior, analysis and design under extreme loads, including seismic, wind and blast, leading structures to nonlinear response, with emphasis on steel structures. He is author of one book in English, on deployable structures, and three books in Greek, on design of unconventional steel structures, structural stability and tension structures. He is also author of 10 book chapters, 81 peer-reviewed journal papers and 150 conference papers. His research work has received more than 950 citations, excluding self-citations and citations by co-authors. He is Editor-in-Chief of the Journal of the International Association for Shell and Spatial Structures (IASS). He is Member of CEN Project Team SC3/T1 of Part 1-1 of Eurocode 3, which is part of the development of the second generation of Structural Eurocodes.
In addition, he is active in structural design and consulting, having participated in design projects of the steel roofs of three major Greek football stadiums, structures for the 2004 Athens Olympic Games, buried pipelines transporting oil and natural gas, underground structures including tunnels and stations for the Athens subway, transmission towers, guyed towers, wind turbine towers, port, marine, energy and industrial facilities projects, as well as the seismic design of the steel gates for the New Panama Canal.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
04/11/2016 @ 12:15 room GCA331

Numerical Modelling in Mechanised Tunnelling

Prof. Dr Emilios Comodromos, Department of Civil Engineering at the University of Thessaly, Greece

Abstract : The continuous development of mechanized tunneling technology substantially improves its effectiveness for the construction of tunnels in urban areas and as a result Tunnel Boring Machines (TBMs) combined with the earth pressure balanced (EPB) shield have been extensively used over the last decades for the construction of tunnels in urban areas. The ability of the EPB method in controlling the induced settlements by regulating the pressure applied to the tunnel face, the pressure beside the shield and the pressure of the mortar behind the final lining renders the method the most effective, particularly in urban areas with loose soils and /or adjacent buildings interacting with tunnels’ construction stages. However, the limitation and requirements on soil subsidence and movements of adjacent buildings demonstrated that many questions remain for the scientific community to resolve regarding the application of the method and the adjustment of various parameters (applied pressures, construction phases, etc.) affecting induced ground movements. The experience gained from the comparison of predictions and observed behavior during tunnelling process demonstrated that an appropriate, safe and cost effective design of a tunnel in urban environment requires reliable computational methods for the prediction of ground movements and induced displacements to adjacent structures, as well as stress relaxation and stress concentration in the vicinity of the tunnel and in final lining, respectively. The first attempts to simulate EPB shield tunnelling were rather simplified and limited to two-dimensional (2D) numerical analysis while in the first efforts of 3D analysis the interaction between the TBM, the grouting behind the shield and the lining was disregarded and the effects were taken into account by considering distributed forces at the circumference of the excavation. Nowadays, the development and continuous advances in numerical methods and computer engineering have provides the capability of multi-stage 3D numerical process taking into account almost all relevant components of shield tunnelling. A case study from the ongoing Thessaloniki subway is presented, addressing the above topics and the assessment of the potential ground and adjacent buildings response.
Bio : Prof. Emilios Comodromos his diploma of civil engineering from the Aristotle University of Thessaloniki (1986) and a D.E.A from École Centrale Paris (1987). In 1991 he has been awarded a Ph.D. degree by the Aristotle University of Thessaloniki for his work in the area of simulation of excavation in elastoplastic soils. His domain of interest, specialization and fields of activity covers the analysis and design of infrastructures involving geotechnical engineering and soil-structure interaction projects (tunnels, foundations, retaining structures, rock-fill dams, embankments, slope stability, reinforced embankments). His professional experience includes the design and consulting services of over 400 projects covering the aforementioned topics. Since 1999 he has been in the Department of Civil Engineering at the University of Thessaly. He is the Head and principal investigator of the Computational Geotechnical Engineering Laboratory. Emilios Comodromos is the author of three books and over 100 journal and conference papers. He is also Reviewer in more than 10 journals in the field of geotechnical engineering (Géotechnique, IJNAMG, ASCE, Computers and Geotechnics, Soils and Foundations, etc).

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
11/11/2016 @ 12:15 room GCA331

Deformation and stress based approaches to the problems of embankment design on soft soils

S. Feyza Cinicioglu, Professor at Istanbul University, Civil Engineering Department, Istanbul, Turkey

Design and construction of embankments on soft clays are associated with a number of problems which show themselves as excessive deformations or catastrophic failures. Traditionally, design and construction are considered as separate processes and there is a strong desire for certainty of cost and outcome at the design stage before construction starts. However, it is not usually possible to meet these requirements due to unforeseen conditions during field investigation process and design stage. An improved version of observational method can be made use of as the only available technique to overcome the difficulties related to the prediction of soil behaviour. The method uses field measurements as the direct inputs to the framework of the constitutive behavior and analyses the behavior synchronously as measurements are recorded. As a result, it is possible to work with current parameters and time lags between capture of measurements, their interpretation leading to parameter revision and corresponding design adjustments are prevented. The framework provided for the application of the method is basically the idealized stress space of the Critical State Theory, but the constitutive anisotropic elastoplastic soil model is mounted on it to analyze the behavior and to provide direct links between measurements and design parameters. Strain rate dependency of the soft soils is also incorporated to the interpretation of the behavior. To consider the variation in the behavior of foundation soils, a zonation system is applied and stress axis rotation is considered. The application of the method is a continuous process and the behaviour can be followed as a real time process throughout the construction and consolidation stages and afterwards. Considerable savings in terms of time and economy can be gained by the application of this method and moreover such an application improves the understanding related to the real behavior of soils. From this viewpoint, an attempt was also made to solve the load sharing mechanism between a soil and a pile subjected to soil movements from an approach embankment, by using deformation and stress values obtained from monitoring and applying a continuous process to follow up the variation in the behavior in a timely manner. The method developed for this purpose is capable to produce the soil response curves which reflect real field behavior through free-field measurements. Load sharing mechanism can be solved realistically with the proposed method for any possible case either the piles are constructed before, during and after embankment construction or for any non-failing or failing state in the responding soil zones. These two methods are real-time methods that discloses the on time behavior during application and enables the implementation of a flexible design process. However, a specific design method that can easily be used in connection with the proposed real time methods could have been useful and in this connection a new embankment design method combining limit state approach with stress path application was also developed. This method is applicable for embankments either constructed in a single stage or multiple stages. Stage construction technique necessitates to add the tool of stress path application to the method, to consider both the undrained and drained behavior. This is a property that is not found in limit state approaches and gives to the method a capacity to follow and interpret changing stress-strain states and their influence on the mobilized strength states. Bio : S. Feyza Cinicioglu received her BSc in civil engineering from Bogazici University, Istanbul in 1974; M.Eng in civil engineering from Sheffield University, UK in 1976. After working as a professional civil engineer between the years of 1976-1983, she joined academia in 1983, received her Ph.D. in the field of geotechnical engineering in 1986 from Bogazici University, Istanbul, Turkey. Since 1995, she has been working as a full professor of Civil Engineering at Istanbul University. She also served as Head of the Department of Civil Engineering (1998-2013), Dean of Graduate School of Science and Engineering (2004-2005), General Secretary (2005-2011) and meanwhile as the President of the Turkish National Society of Soil Mechanics and Geotechnical Engineering (2011- ). Her major areas of research are design and construction of embankments on soft clays, macro and micro soil behavior, soil-structure interaction and seismic microzonation. She has directed several application projects such as; seismic risk assessment of Bakirkoy and Omerli Regions of Turkey (these projects have been implemented by the municipalities of these regions and they are currently effective), research projects on the subjects of development of new methodologies for embankment design and construction on soft clays, micro and macro mechanical behavior of soft soils, behavior of piled bridge abutments. Her refereed articles appeared in a variety of journals including ASCE journal of geotechnical and geoenvironmental engineering, Canadian geotechnical journal, engineering geology, ASCE international journal of geomechanics.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
18/11/2016 @ 12:15 room GCA331

CO2 storage in and CH4 recovery from coals seams: adsorption-induced stresses and variations of permeability

Prof. Dr Matthieu Vandamme, Assistant Professor and Researcher at Laboratoire Navier, Ecole des Ponts ParisTech, Université Paris-Est, Champs-sur-Marne, France

Abstract : During production of methane from deep coal seams, or during injection of carbon dioxide in those seams, very significant variations of permeability are observed, which need to be understood and modeled.
Coal contains micropores (i.e., pores with a diameter smaller than 2 nm), in which pore fluid is adsorbed, i.e., in which most fluid molecules are in intermolecular interaction with the atoms of the coal solid. Variations of permeability of the seam are a consequence of this adsorption in sub-nanometer pores: adsorption induces an expansion of the coal matrix, and hence a closure of the cleat system (i.e., a set of fractures naturally present in the coal bed), which in turn leads to a decrease of permeability.
In terms of modeling, we present an extension of the poromechanical approach to microporous solids and adsorption effects. One originality of the model is that, rather than focusing on strains induced by adsorption, we focus on the mechanical stresses this adsorption induces. Experimentally, we show on intact coal cores (i.e., in the lab) that adsorption can induce mechanical stresses of several dozen MPa and variations of permeability of more than two orders of magnitude (as observed in the field), and that desorption can even lead to mechanical failure of the coal sample.

Bio : Matthieu VANDAMME received his Ph.D. from the Civil and Environmental Engineering department at MIT (Cambridge, MA) in 2008, for a study of the creep properties of cementitious materials by nanoindentation. He is also engineer from Ecole Polytechnique (France) and from École Nationale des Ponts et Chaussées (France), and received an M.S. in solid mechanics from École Nationale des Ponts et Chaussées in 2002. He was awarded the 2016 ASCE EMI Leonardo da Vinci Award.

Since 2008, he has been working at Laboratoire Navier (ENPC, CNRS, IFSTTAR), at École Nationale des Ponts et Chaussées. He performs Materials Science applied to materials relevant for Civil and Petroleum Engineering (i.e., cementitious materials, coal, clay-based materials…). More precisely, his main interest lies in the mechanics and physics of porous solids.

More information can be found at: http://navier.enpc.fr/~vandamme

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
25/11/2016 @ 12:15 room GCA331

Exploiting the potentials of High-Strength-Steels: Damage mechanics approach to describe upper shelf fracture behaviour

Prof. Dr Markus Feldmann, Full Professor at RWTH Aachen University, Aachen, Germany

In the actual Steel Design Codes, especially for strength oriented cases, ultimate load and fracture are considered as a phenomenon being linked to the material strength f_u in engineering model approaches. However, since the material strength f_u is primarily the result of the occurrence of plastic instability in tension, it does not sufficiently reflect the damage behaviour of the material. Thus it is necessary to take into account the damage behaviour to predict fracture for stress states that are different from that of pure tension and especially when notches come into play. This situation results into two main shortcomings at present:
1)    Relative high scatter in the actual components strength prediction
2)    Utilisation potential for new, i.e. High Strength and Ultra High Strength Steels,
       at present not used
       The presentation therefore outlines in the light of using High Strength Steels:
       -    a procedure how these obstacles can be overcome and which
            approaches are feasible based on damage mechanics
       -    which parameters do we need and
       -    how a reduced parameter determination technique can be applied.
Additonally some results on notched tension bars are presented and discussed vis à vis experimental results.

Bio : M. Feldmann got a Civil Engineering degree at RWTH Aachen University, Dipl.-Ing. in 1991. He then went into industry as a Design Engineer for 2 years. At the end of 1992, he came back to RWTH Aachen University as a PhD and got his Doctoral Degree in 1994, with the thesis entitled:
Zur Rotationskapazität von I-Profilen statisch und dynamisch belasteter Träger.
He was then Chief Engineer at the Steel Construction Institute of RWTH Aachen University, 1995-1998 and went again for 3 years in industry.
He was appointed Full Professor for Steel Construction at TU Kaiserslautern, in 2002. Then he was appointed Full Professor at RWTH Aachen University, in 2004/2005.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
09/12/2016 @ 12:15 room GCA331

Effectiveness and Equity in Pickup and Distribution Problems

Prof. Dr Michal Tzur, Industrial Engineering department, Tel Aviv University, Tel Aviv, Israel

We study the logistic challenges of a food bank that, on a daily basis, uses vehicles of limited capacity to collect donated food from suppliers in the food industry and distribute it to welfare agencies. We model this problem as a routing – resource allocation problem, with the aim of maintaining equitable allocations to the different agencies, while delivering overall as much food as possible. We introduce an innovative objective function that satisfies desired properties of the allocation, that is easy to compute and implement within a mathematical formulation, and that balances effectiveness and equity acceptably. We present an exact solution method, upper bounds, and a heuristic approach. Numerical experiments on several real-life and randomly generated datasets confirm that high-quality solutions may be obtained. Some implementation issues will be discussed, concerning the integration of our solution method into the information systems of the Israeli food bank with whom we cooperate.
Joint work with Ohad Eisenhandler

Bio : Michal Tzur is a professor in the Industrial Engineering Department of the Faculty of Engineering, Tel Aviv University, Israel. She received her Ph.D. in Management Science from the Graduate School of Business at Columbia University in the city of New York. She was a faculty member in the business school of the University of Pennsylvania (Wharton School) and a visiting faculty member in the department of Industrial Engineering and Management Sciences (IEMS) at Northwestern University. Her main research interests are in the areas of humanitarian logistics, vehicle sharing systems, vehicle routing and supply chain management. Since 2015 she serves as the president of the Operations Research Society of Israel (ORSIS).

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
16/12/2016 @ 12:15 room GCA331

Earthquake engineering of nonstandard concrete structures: from the assessment of spatial variability of earthquake signals to numerical modelling of structural response

Prof. Dr Frédéric Dufour, Professor at 3SR laboratory and Vice President for research of Grenoble Institute of Technology, Grenoble, France

Over the last 30 to 40 years, modern design codes have been developed worldwide to increase the safety of civil engineering structures against an earthquake. For practical/economic reasons they mainly focus on classical structures to be built with restrictive hypothesis to allow simple engineering analysis. However, historical monuments and large structures for energy production (dams, nuclear power plants) need a specific attention of the scientific community.
Large structures for energy production have a huge interfacial surface with the ground. Therefore, the hypothesis of having a homogeneous loading must be questioned. Several sensor networks have been set in the world to analyze the amplitude and phase changes in space due to complex wave propagation in the underground. More recently, a dam has been instrumented with about 20 velocimeters to measure the spatial variability both under ambient noise and seismic events. The effect of topography on the phase and amplitude heterogeneities is analyzed with the help of spectral element models. The objective is to better identify the real loading felt by large structures and to identify whether the spatial variability is more or less critical for the structural safety.
Besides, for ancient/historical structures classical engineering methods are not valid. Thus, one needs to use modern finite element codes to assess the earthquake safety of such structures. Dynamic analyses have the potential to evaluate accurately local information (damage, crack opening, rebar yielding, etc.) although the computational time may be a drawback. Therefore, simplified numerical methods may be used for specific structures. For instance, the number of degrees of freedom of the model can largely be reduced by applying beam kinematic for some structural elements. This yields to the development of multifiber beam finite elements. Recently warping has been added to those models to account for shear deformation in the damage of concrete and yielding of rebars.
Finally, for the purpose of a probabilistic risk analysis in engineering design, one must rely on an efficient intensity measure to estimate the structural response. For instance, the well-known PGA accounts only for the signal measure without taking into account the modal analysis of the structure. Thus, it cannot be reliable for any structures since it does not account for resonance. Besides, by definition the spectral acceleration (SPa) is the best intensity measure for a single degree of freedom system with a linear behavior. However, real structures may undergo nonlinear behavior under intense earthquake. Recently, a new intensity measure has been developed accounting for the fundamental frequency of the structure and arbitrarily its reduction upon structural damage. This IM called ASA40 has been proved to be simple and efficient, although in some specific case a time-frequency analysis remain necessary to evaluate structural damage.

Bio : Prof. Frédéric Dufour obtained his PhD from the University of Nantes and Ecole Centrale of Nantes in 2002. He is now professor at Grenoble Institute of Technology in the 3SR laboratory and Vice President for Research of the Grenoble Institute of Technology. He is the head of the PERENITI Chair funded by EDF on the reliability of large structures. His research interests comprise the numerical modelling of complex fluids and the modelling of concrete structures with non-local approaches. Prof Dufour is the co-author of about 30 peer review journal papers with a h-index of 12 and 400 citations.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
24/02/2017 @ 12:15 room GCB330

Modelling degradation processes of cement-based materials by means of mechanics of multi-phase porous media

Prof. Dr Dariusz Gawin, D.Sc., Ph.D., M.E., The Łódź University of Technology, Łódź, Poland
A general approach [1] to modelling various degradation processes in cementitious materials, due to combined action of variable hygral, thermal, chemical and mechanical loads, will be presented. Mechanics of multiphase porous media and damage mechanics are applied for this purpose. Kinetics of physico-chemical processes, like for example: cement hydration [2,3], salt crystallization/dissolution [4], calcium leaching [5], Alkali Silica Reaction (ASR) [6], and water freezing/thawing [7], is described with evolution equations based on thermodynamics of chemical reactions. The mass-, energy- and momentum balances, the evolution equations describing chemical reactions and deterioration processes, as well as the constitutive and physical relations will be presented. The mutual couplings between the chemical, hygral, thermal and mechanical processes will be discussed, both from the viewpoint of physicochemical mechanisms and mathematical modelling. Numerical methods used for solution of the model governing equations will be presented. For this purpose the finite element method is applied for space discretization and the finite difference method for integration in the time domain.
Several examples of the model application for analysing transient chemo-hygro-thermo-mechanical processes in cementitious materials will be solved and discussed. The first example deals with concreting and maturing of massive structure. The second example concerns calcium leaching from a concrete wall due to chemical attack of pure water, exposed to gradients of both temperature and pressure. The third one describes cracking of concrete element, caused by development of expanding products of ASR. The fourth example concerns the salt crystallization during drying of a wall made of concrete/ceramic brick, causing degradation of a surface layer due to development of crystallization pressure. The last example concerns freezing and thawing of a wet concrete wall in variable temperature and relative humidity, causing frost damage.
REFERENCES
[1] D. Gawin, M. Koniorczyk and F. Pesavento, “Modelling of hydro-thermo-chemo-mechanical phenomena in building materials”, Bulletin of The Polish Academy of Sciences: Technical Sciences, Vol. 61(1), 51-63, (2013).
[2] D. Gawin, F. Pesavento, B.A. Schrefler, Hygro-thermo-chemo-mechanical modelling of concrete at early ages and beyond. Part I: Hydration and hygro-thermal phenomena, Int. J. Num. Meth. Engng, Vol. 67, No. 3, 299-331 (2006)
[3] D. Gawin, F. Pesavento, B.A. Schrefler, Hygro-thermo-chemo-mechanical modelling of concrete at early ages and beyond. Part II: Shrinkage and creep of concrete, Int. J. Num. Meth. Engng, Vol. 67, No. 3, 332-363 (2006)
[4] M. Koniorczyk, D. Gawin, “Modelling of salt crystallization in building materials with microstructure - poromechanical approach”, Construction and Building Materials, Vol. 36, 860-873 (2012).
[5] D. Gawin, F. Pesavento and B.A. Schrefler, “Modeling deterioration of cementitious materials exposed to calcium leaching in non-isothermal conditions”, Computer Methods in Applied Mechanics and Engineering, Vol. 198(37-40), 3051-3083, (2009).
[6] F. Pesavento, D. Gawin D., M. Wyrzykowski, B.A. Schrefler and L. Simoni, “Modeling alkali-silica reaction in non-isothermal, partially saturated cement based materials”, Computer Methods in Applied Mechanics and Engineering, Vol. 225-228, 95-115, (2012).
[7] Koniorczyk M., Gawin D., Schrefler B.A., Modelling evolution of frost damage in fully saturated porous materials exposed to variable hygro-thermal conditions, Computer Methods in Applied Mechanics and Engineering, Vol. 297, 38-61 (2015).

Short Bio : Prof. Dariusz Gawin got his Ph.D. in 1990 in Civil Engineering, Łódź University of Technology and his D.Sc.in 2001 in Building Physics, Łódź University of Technology both with honours. His has the position of an ordinary professor at the same University and is also Vice-rector of the University for Innovations and Development. He is also the Head of Building Physics and Building Materials Department. Between 1993 and 1994 he was a Post-doctoral fellow at University of Padova, Italy. In 1999 he joined Oak Ridge National Laboratory, Oak Ridge (TN), USA as a Post-doctoral research associate.
From 2001-2005 he was a visiting professor at the Faculty of Engineering at University of Padua, Italy and again he was a visiting researcher at the same faculty from 2013-2014.
His research areas are :
- Durability of building materials – numerical modelling with mechanics of multiphase porous materials;
- Sustainable buildings, energy efficiency and energy auditing of a building;
He published up to now 9 books and monographs; 98 papers in scientific and technological journals (42 in the Web of Science database); 44 chapters in scientific books; 252 papers on international and national scientfic conferences; 63 publications included into the Web of Science database were cited >1390 times (>1110 without auto-citations) resulting in the Hirsch index h= 19
Organized by Prof. Dr Brice Lecampion & Prof Dr Katrin Beyer
03/03/2017 @ 12:15 room GCB330

A crowdsourced physical internet for small parcels delivery

Dr Tal Raviv, Tenured senior Lecturer Industrial Engineering Dept, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Israel

The rapid growth of e-commerce has caused a significant increase in the volume that passes through the parcel delivery industry. Recent advances in the mobile computing technology created new opportunities to redesign the delivery process to make it more efficient and sustainable. Our idea is to utilize the journeys that regular people are making with their cars, to ship small parcels.
We envision a novel logistic process for delivering small parcels by people who subscribe as occasional curriers (OCs). A network of automatic service points (SPs) with lockers is deployed and used as locations where parcels can be dropped off by the senders and picked up by the recipients. The SPs also serve as intermediate transfer points where parcels can be dropped off by OCs and picked up again later by other OCs. Thus, we use the term physical internet to describe this network. The SPs are strategically located in accessible sites such as gas stations.
The OCs install a location-aware mobile app that offers them monetary rewards to transfer parcels between the SPs during their regular car journeys. The parcels can be transferred to their desired destination SP or intermediate SPs.
We devised a method to route the parcels in the system by determining the offers that the system should make to the OCs such that the expected operational cost is minimized. This cost consists of the payments to the OCs and penalties that are paid to the customers for late delivery. The method is based on a Markov Decision Process (MDP) that solves a simplified version of the problem efficiently. Next, we devised a more complex incentive mechanism that allows greater profits for the OCs and the operator by reinforcing consolidation of shipments. A heuristic method to resolve this mechanism is proposed. The method combines the policy obtained from the simplified MDP with local solutions of loading optimization problems that are formulated and solved as a mixed integer program.
We conducted a simulation study using realistic data on the movement of people and parcels. Our preliminary results demonstrate that such a system can provide next day delivery service at a very low operational cost. The system can handle a large volume of parcel traffic by utilizing the excess capacity of private cars in a small fraction of the journeys that the public is doing anyway. The ratio between the rewards paid to the OCs and our conservative estimate of the time needed to handle the parcels is well above the average hourly wage while the average cost of delivering a parcel is significantly below the market price of this service.

Joint work with Eyal Tenzer

Short Bio : Tal Raviv is a tenured senior lecturer Industrial Engineering department at the Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Israel. He holds a BA from the Eitan Berglas School of Economics, Tel Aviv University (1993), an MBA from the Recanati School of Business, Tel Aviv University (1997), and a PhD in Operations Research from the William Davidson Faculty of Industrial Engineering and Management, Technion - Israel Institute of Technology, Haifa (2003). He spent two years (2004-2006) as a postdoctoral fellow in the Sauder School of Business at University of British Columbia, Vancouver, Canada. His current primary research interest is in transportation and logistics with a focus on shared mobility systems and sustainable logistics.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
10/03/2017 @ 12:15 room GCB330

Evaluating the seismic risk of existing tall buildings in the Western United States

Prof. Dr Carlos Molina Hutt, Environmental and Geomatic Engineering (CEGE) Department at University College London (UCL), England

Abstract : Tall buildings play an important role in the socio-economic activity of major metropolitan areas in the United States. In areas of high seismicity, the design of many existing tall buildings followed historic code-prescriptive requirements that do not provide an explicit understanding of performance during major earthquakes. This presentation will share the results of an evaluation of the seismic risk of these buildings using San Francisco, CA as a case study. By means of an inventory of the existing tall building stock, an archetype building was developed to represent the state of design and construction practice from the mid-1970s to the mid-1980s. An intensity based assessment was carried out to evaluate performance under a design level earthquake in terms of structural response, economic losses and downtime. Furthermore, conceptual retrofit strategies to achieve increased levels of resilience were also evaluated. In order to benchmark the performance of older existing tall buildings against modern seismic design standards, a comparative risk-based assessment was also carried out to evaluate collapse risk and other performance metrics.

Bio : Carlos Molina Hutt is a member of academic staff in the Civil, Environmental and Geomatic Engineering (CEGE) Department at University College London (UCL) where he teaches graduate and undergraduate courses structural analysis and design. Prior to joining UCL, Carlos worked as a structural engineer with Arup in New York, where he gained experience in the design of numerous high rise buildings in Mexico City which adopted a Performance Based Seismic Design approach. Carlos is a registered Professional Engineer (PE) in the State of California in the United States of America and a Chartered Engineer Member of the Institution of Civil Engineers (CEng MICE) in the United Kingdom.
Carlos obtained his master’s degree from Stanford University, where he first gained interest Earthquake Engineering. When he started working as a structural engineer, his continued interest in seismic engineering led him to enrol in a part-time engineering doctorate degree at UCL co-supervised by Stanford University, with Arup as industrial partner. After four years of working at Arup, Carlos relocated to UCL as a member of academic staff to continue his research work towards completion of his part-time PhD within the Earthquake and People and Interaction Centre (EPICentre) and to lecture in UCL’s MSc program in Earthquake Engineering with Disaster Management, as well as the BSc and MSc degree programs in Civil Engineering.
Carlos’ research encompasses computational methods emphasizing nonlinear simulation of structural performance in tall buildings, performance-based earthquake engineering and resilience-based design. Carlos has worked on collaborative research projects involving researchers and practitioners from the United States, China and the United Kingdom.

Organized by Prof.Dr Brice Lecampion & Prof. Dr Katrin Beyer
10/03/2017 @ 12:15 room GCB330

Evaluating the seismic risk of existing tall buildings in the Western United States

Prof. Dr Carlos Molina Hutt, Civil, Environmental and Geomatic Engineering (CEGE) Department at University College London (UCL), England

Abstract : Tall buildings play an important role in the socio-economic activity of major metropolitan areas in the United States. In areas of high seismicity, the design of many existing tall buildings followed historic code-prescriptive requirements that do not provide an explicit understanding of performance during major earthquakes. This presentation will share the results of an evaluation of the seismic risk of these buildings using San Francisco, CA as a case study. By means of an inventory of the existing tall building stock, an archetype building was developed to represent the state of design and construction practice from the mid-1970s to the mid-1980s. An intensity based assessment was carried out to evaluate performance under a design level earthquake in terms of structural response, economic losses and downtime. Furthermore, conceptual retrofit strategies to achieve increased levels of resilience were also evaluated. In order to benchmark the performance of older existing tall buildings against modern seismic design standards, a comparative risk-based assessment was also carried out to evaluate collapse risk and other performance metrics.

Bio : Carlos Molina Hutt is a member of academic staff in the Civil, Environmental and Geomatic Engineering (CEGE) Department at University College London (UCL) where he teaches graduate and undergraduate courses structural analysis and design. Prior to joining UCL, Carlos worked as a structural engineer with Arup in New York, where he gained experience in the design of numerous high rise buildings in Mexico City which adopted a Performance Based Seismic Design approach. Carlos is a registered Professional Engineer (PE) in the State of California in the United States of America and a Chartered Engineer Member of the Institution of Civil Engineers (CEng MICE) in the United Kingdom.
Carlos obtained his master’s degree from Stanford University, where he first gained interest Earthquake Engineering. When he started working as a structural engineer, his continued interest in seismic engineering led him to enrol in a part-time engineering doctorate degree at UCL co-supervised by Stanford University, with Arup as industrial partner. After four years of working at Arup, Carlos relocated to UCL as a member of academic staff to continue his research work towards completion of his part-time PhD within the Earthquake and People and Interaction Centre (EPICentre) and to lecture in UCL’s MSc program in Earthquake Engineering with Disaster Management, as well as the BSc and MSc degree programs in Civil Engineering.
Carlos’ research encompasses computational methods emphasizing nonlinear simulation of structural performance in tall buildings, performance-based earthquake engineering and resilience-based design. Carlos has worked on collaborative research projects involving researchers and practitioners from the United States, China and the United Kingdom.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
17/03/2017 @ 12:15 room GCB330

Sediment replenishment : a few feedbacks on implementation and monitoring issues

Prof. Dr M. Hervé Piégay, Géographe, CNRS - National Centre of Scientific Research, ENS of Lyon, France

Sediment replenishment (or gravel augmentation) is becoming a popular restoration measure in rivers affected by a sediment deficit and paved, notably in the Alps and their surroundings. The aim of this talk is to introduce a few examples where this measure has been experimented focusing on feedbacks to learn from these experiences and promote adaptive management. We will explore the justification and the critical questions operators are faced to when implementing such actions, such as the amount of sediment needed, the frequency of injection, the design of injection, the available sediment sources, the risks associated with such measures and their potential benefits. Some challenging issues will be introduced in term of monitoring design with the development of active and passive RFID technology to survey gravel mobility and large-scale regional approach to move from opportunistic to targeted actions.

Short Bio :
Hervé Piégay is Research Director at CNRS – National Centre of Scientific Research, ENS of Lyon, France. His research interests range from river contemporary changes to process monitoring and characterisation of fluvial corridors by ground and airborne imagery. He is involved in integrated sciences for rivers and is strongly interacting with practitioners (Water Agencies, Regions, Ministry of Ecology, ONEMA, Compagnie Nationale du Rhône, EDF) providing knowledge for river management, planning and restoration and methodological frameworks and tools using GIS and remote sensing. Since 2010, he is the research leader of the scientific team working on the Rhône valley, being in charge of the Rhône Observatory of Human and Environment Interactions.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
24/03/2017 @ 12:15 room GCB330

Coupled simulation of faulted porous media

Prof. Dr Massimiliano Ferronato, Associate Professor at the Department of Civil, Environmental and Architectural Engineering, ICEA, University of Padova, Italy

Abstract : Poromechanical models are currently of common use in a number of engineering applications, including the management of deep hydrocarbon reservoirs, used for both production and storage purposes, and the exploitation of groundwater resources from shallow multi-aquifer systems. Recently, an increasing interest is set at introducing discontinuity surfaces in the numerical models to simulate the mechanics of geological faults. For instance, such an activity is of paramount importance for ensuring the safety of the underground storage of wastes and hydrocarbons or predicting the possible seismicity triggered by the production and injection of subsurface fluids.
The stable numerical modelling of coupled poromechanics and the ground rupture formation, however, is still a challenging task because of several issues, namely: (1) the pore pressure numerical instability, (2) the strong non-linearity induced by the fault activation, (3) the large number of unknowns, and (4) the severe ill-conditioning of the discrete problem. A number of different approaches have been proposed in recent years to alleviate such difficulties. Among them, Mixed Finite Element formulations of coupled poromechanics and the use of Lagrange multipliers to prescribe the contact constraints on the fault surfaces can help alleviate the numerical oscillations and provide a mass-conservative approach, but typically give rise to very large and ill-conditioned systems of algebraic equations.
In the present work, the mathematical weak formulation of the problem is modified in order to take into account the frictional energy along the activated fault portion according to the principle of maximum plastic dissipation. This helps providing stable solutions with a fast convergence of the non-linear fault problem. Moreover, a novel class of efficient block preconditioners is developed with the aim of accelerating the convergence of Krylov subspace methods in complex real-world applications. The main idea relies on building cheap and effective approximations of the two-level Schur complement using a physics-based approach. A purely algebraic formulation is also advanced, thus allowing for the extension to different kinds of coupled multi-physics problems.
Applications of the proposed approach are presented in problems related to the generation of ground fractures due to groundwater withdrawal in arid regions, fault reactivation in active hydrocarbon reservoirs, and the exploitation of groundwater resources from a regional multi-aquifer system.

Bio : Massimiliano Ferronato got the Degree in Civil Engineering at the University of Padova (Italy) in 1998 and the PhD in Numerical Geomechanics at the Technology University of Delft (The Netherlands) in 2003. Currently, he is Associate Professor at the Department of Civil, Environmental and Architectural Engineering of the University of Padova, with teaching duties in the Numerical Methods classes.
He has authored and co-authored more than 150 scientific papers published in international journals, books and proceedings of international conferences, and delivered invited talks and lectures in several renowned symposia. The main scientific interests concern the numerical solution of the partial differential equations governing the mechanics of saturated and partially saturated porous media, with engineering applications in the field of subsurface hydrology and petroleum engineering. He has been involved in a number of projects related to the numerical simulation of the geomechanical behavior of deep producing reservoirs, geological formations used for storage purposes, e.g., CO2 sequestration, and shallow multi-aquifer systems, including the analysis of fault activation, fissure generation, failure risk and land subsidence. The main scientific contributions concern the development and implementation of efficient and robust numerical models, based on Finite Element, Mixed Finite Element and Finite Volume methods, for the simulation of geomechanical and fluid-dynamical processes in the subsurface. Particular care is paid to the implementation of accurate iterative solvers for the linear systems arising from such applications. He is the co-author of a number of original algorithms for both sequential and parallel computational architectures, with the aim of accelerating the convergence and improving the robustness of iterative linear solvers.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
07/04/2017 @ 12:15 room GCB330

Recent developments on topological derivative methods for qualitative inverse scattering

Prof. Dr Marc BONNET, POEMS (ENSTA, CNRS, INRIA, Université Paris-Saclay), Palaiseau, France

The topological derivative quantifies the sensitivity of objective functionals whose evaluation involves the solution of a PDE with respect to the nucleation of a small feature (e.g. cavity, inclusion, crack) at a prescribed location in the (e.g. acoustic, elastic, electromagnetic) medium of interest. Originally formulated in the context of topology optimization, the concept of topological derivative has also proved effective as a qualitative inversion tool for wave-based identification of either small or finite-sized objects. In that approach, hidden objects are deemed to lie at locations where the topological derivative is most negative. Topological derivatives need asymptotic analysisfor their derivation, but are then very simple to implement and entail computational costs that are much lower than straightforward optimization-based inversion methods. Focusing on acoustic and elastodynamic scattering, and stressing main concepts and results rather than technical detail, the following topics will be addressed: 1) An overview of inverse scattering approaches relying on asymptotic expansions for small scatterers. 2) Asummarized presentation of the derivation of topological derivatives for acoustic and elastodynamic scattering, including small-inclusion asymptotics based on the expansion of Lippmann-Schwinger volume integral equations. 3) The implementation of topological derivative and numerical experiments. 4) Going beyond the above heuristic-based use of the topological derivative, a (partial in scope) justification is presented for the acoustic
case involving far-field measurements (collaboration with Cedric Bellis and Fioralba Cakoni). 5) Higher-order expansions, providing approximations of objective functionals that are polynomial in the defect diameter (with coefficients depending on trial defect location and assumed physical properties) and permitting quantitative identification within moderate computational costs, will finally be addressed
Bio : Marc Bonnet, a CNRS senior scientist, is with the POEMS group of the Applied Mathematics department of ENSTA since 2011, and was before that with the Solid Mechanics laboratory (LMS) of Ecole Polytechnique. He completed master studies in solid mechanics in 1983 (université Paris 6, concurrently with the engineering degree of ENPC, Paris), obtained his doctor degree from ENPC in 1986 and his habilitation degree from Université Paris 6 in 1995. His research interests include inverse problems, integral equation methods and asymptotic models for elastic and acoustic wave propagation problems. He is associate editor or editorial board member of several international research journals (Inverse Problems, Engineering Analysis for Boundary Elements, Journal
of Integral Equations and Applications, Inverse Problems in Engineering and Sciences, Computational Mechanics, Journal of Optimization Theory and Applications).

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
28/04/2017 @ 12:15 room GCB330

Embedding autonomy in Intelligent Transport Systems

Prof. Dr Elias B. Kosmatopoulos, Department of Electrical and Computer Engineering, Democritus University of Thrace, Santhi, Greece

The recent very impressive advances in cooperative systems, the Internet of Things (IoT), sensor technologies and Data Analytics for Intelligent Transport Systems (ITS), gave rise to a new generation of tools and systems for optimizing the situation awareness of the traffic/transport operator as well as of the traffic/transport user (driver, passenger). However, optimizing the situation awareness of traffic/transport operations is by no means enough for the operator or the user to take the optimal decisions regarding the ITS operation: the complexity and scale of the different operations involved, renders the problem of taking optimal - or, at least efficient - decisions a quite difficult one. This is probably the main reason the efficient operation of ITS, requires a quite tedious and costly effort for designing and tuning its decision-making mechanisms. Moreover, as the ITS is a "living system" such a tedious and costly effort is not only required during the initial deployment of the system but during its lifetime. Urban and motorway traffic control systems, Transport Management Systems (TMS) for public transport systems and TMSs for large-scale railway, airport and seaport operations are all examples of ITS where such a tedious and costly effort is required during the system deployment and during its lifetime.
We have recently introduced and extensively test a new approach towards overcoming the above-mentioned problem. Our proposed approach concerns embedding autonomy within the ITS which neglects the need for tedious and costly manual effort. Extensive - both simulation-based and real-life -tests demonstrated that such an appproach can lead to substantial improvements in the ITS operation while leading to minimum-possible deployment and operational costs. The aforementioned tests concerned many different ITS from conventional urban and motorway control systems to cooperative and fully autonomous vehicles. During this talk, we will describe the methodology used for embedding autonomy, the results achieved as well as issues raised and need to be addressed.

Bio : Elias B. Kosmatopoulos is a Professor with the Department of Electrical and Computer Engineering, Democritus University of Thrace, Xanthi, Greece. Previously, he was a faculty member of Technical University of Crete, Greece and University of Southern California, USA. He has been leading many research projects funded by the European Union with a total budget of about 10 Million Euros. Prof. Elias Kosmatopoulos, established on 2009 the ConvCao researh group, which focuses on the development of intelligent, rapidly-deployable and self-adaptable IoT and CyberPhysical systems and their application to large-scale real-life systems including intelligent traffic systems, energy efficient systems, robotic swarms and teams of cooperating humans and robots. The results, tools and products of the ConvCao group have been successfully implemented in a variety of real-life systems including: large-scale traffic control systems where they have led to improvements (in terms of fuel consumption) of more than 50%; large-scale buildings and blocks of buildings where they have led to improvements (in terms of energy bills) in the range of 20%-50%; teams (swarms) of aerial and underwater robots where they have led to improvements (in terms of speed, accuracy and cost of operation) of 100% and more.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
05/05/2017 @ 12:15 room CE1103

Assessing the capacity of turbulent flows to conduct geomorphic work

Prof. Dr Manousos Valyrakis, Lecturer in Water Engineering, School of Engineering, University of Glasgow, U.K.

The primary focus of this research is to investigate the potential of a recently proposed criterion for the precise identification of the hydrodynamic conditions responsible for the onset of entrainment of coarse grains. Knowledge of such near critical flow conditions is important for a variety of applications ranging from environmental hydraulics (such as protection of hydraulic structures from scour) to stream ecology, with regard to the assessment of the ecologically and environmentally sound flow conditions for the protection of stream habitat. Recently introduced theoretical concepts as well as probabilistic modeling approaches are presented. At near incipient flow conditions the magnitude of energetic flow events follows a power law distribution, over a wide range of frequencies, similar to many other geophysical phenomena. This implies that highly energetic flow structures, which have a good potential of impinging on an exposed particle and displacing it downstream, occur less frequently for the same low mobility flow conditions. This is in agreement with the intermittent and episodic character of particle entrainment observed from mobile particle flume experiments at low mobility flows. However, small changes in the mean flow or bed shear stresses may result in significant changes in the distribution of these flow structures. Further, analysis of synchronous time series of particle entrainment and local instantaneous flow upstream of it, allows for extraction and characterization of the scales and magnitudes that are relevant to the displacement of individual particles. In addition to having a sound theoretical basis, the stochastic modeling approach is shown to perform well in defining the condition of incipient motion and more generally the various levels of probability for particle entrainment.
Bio : Dr. Manousos Valyrakis is a Lecturer in Water Engineering, within the School of Engineering at the University of Glasgow. Before joining the University of Glasgow, he worked at Virginia Tech and VCCER as a Research Associate, where he further researched the environmental impacts and associated risks from the resource extraction industries. He gained a PhD in Environmental Hydraulics from the Department of Civil Engineering at Virginia Tech, funded by NSF, in 2011. He has a Diploma (5 year degree) in Civil Engineering, with distinctions and an MSc (Civil and Environmental Engineering), from Aristotle University of Thessaloniki.

Dr. Valyrakis has about 15 years of experience in environmental hydraulics and experimental/computational fluid mechanics. He is the recipient of several awards and has served as session chair on several international conferences. He has also served as a reviewer and member of the editorial board for a book and many international journals and conferences. He has been invited to present his research on several venues and he has authored or co-authored more than 40 outputs, including many peer reviewed journal papers and 2 invited book chapters.

He is the manager of the Water Engineering Laboratory (Rankine Building) where he is currently leading research activities relevant to experimental flow dynamics and eco-hydraulics.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
12/05/2017 @ 12:15 room GCB330

About the hydro-mechanics of fractures and fracture networks in rocks

Prof. Dr.-Ing. Holger Steeb, Professor (W3) at Faculty of Civil and Environmental Engineering, Institute of Applied Mechanics (CE), Dept of Continuum Mechanics, University of Stuttgart, Germany

A comprehensive understanding of the physical properties of seismic waves (like dispersive phase velocities and/or attenuation) in fractured porous rocks is important in various fields like hydrocarbon and geothermal exploration/exploitation or water reservoir management. E.g. characterization of subsurface fluid flow requires accounting for hydromechanical coupling between fluid-pressure variations in conduits and related rock deformation.
In this presentation, modeling aspects and numerical simulations of a (weakly) compressible fluid along compliant hydraulic conduits, such as joints or fractures/fracture networks, are investigated. In order to efficiently describe transport processes andpressure diffusion through fractures with realistic geometries, i.e., characterized by high aspect ratios, a hybrid-dimensional approach is discussed and applied to harmonic pumping tests. Further, it will be shown that this modeling approach could be also applied to derive effective hydro-mechanical properties of reservoir rocks on the REV scale in an
efficient way. The consistent computational homogenization approach is therefore based on an extended Hill-Mandel macrohomogeneity condition. In the numerical studies, synthetic fracture networks in a periodic unit cell are stochastically generated representing typical reservoir scenarios. The resulting fluid-filled (fractured) poroelastic rock is numerically investigated by coupled Finite Element Methods. From the numerical results in the time-domain, we determine an effective pseudo-Skempton coefficient using computational homogenization approaches to replace the heterogeneous medium by a macroscopic, homogeneous viscoelastic substitute medium. The effective pseudo-Skempton coefficient captures two viscous attenuation phenomena, pressure diffusion
parallel to the fractures and leak-off perpendicular to the fractures. The two attenuation mechanisms are caused by viscous solid-fluid momentum interaction but are related to different inherent diffusion lengths and characteristic times (or frequencies). We discuss how the analysis of the effective pseudo-Skempton coefficient in frequency space provides a valuable tool for the analysis of interconnectivity of fracture networks and for the determination of aspect ratios of fractures in reservoirs.

Short Bio : Prof. Dr.-Ing. Holger Steeb got his Civil Engineefing Degree from University of Stuttgart, Germany in 1995. In 2002 he obtained his doctoral degree in Engineering from University of Stuttgart and in 2008, his habilitation degree in Mechanics, at Saarland University, Saarbrücken, Germany.
In 2004 he was a Post-Doc Fellow at Faculty of Applied Mathematics and Phisics, NTUA Athens, Greece and between 2002-2008 Academic Staff and Lecturer at Saarland, University, Saarbrücken.
From 2008-2009 he was an assistant Professore for Multi-Scale Mechanics at University of Twente, Enschede, The Netherlands. From 2009-2015 he was Professor for Continuum Mechanics, Ruhr-University Bochum, Germany and since 2015 he is Professor for Computational Continuum Mechanics, Institute of Mechanics, University of Stuttgart.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
19/05/2017 @ 12:15 room GCB330

Seismicity triggered by fluid injection-induced aseismic slip

Prof. Frédéric Cappa, Géoazur laboratory, University of Nice Sophia Antipolis, France

Abstract:
In the upper crust, fluid pressures are known to induce both earthquakes and aseismic deformations. However, the mechanisms involved are poorly understood and our ability to assess the seismic hazard associated with natural and anthropogenic fluid pressurization remains limited. In this talk, I will show how in-situ fluid injection experiments at meter scale can contribute to improve our understanding of how fluid pressure affects the different modes of fault slip and what it tells about the link between seismicity, aseismic creep and fluid diffusion. In our field experiments, we directly measure fault slip and seismicity induced by fluid-injection into a natural fault. The main results indicate highly dilatant and slow ([endif]-->) aseismic slip associated with a 20-fold increase of permeability, which transitions to faster slip ([endif]-->) associated with reduced dilatancy and micro-earthquakes. Mostly aseismic slip occurs within the fluid-pressurized zone and obeys a rate-strengthening friction law. Fluid-injection primarily triggers aseismic slip in this experiment with micro-earthquakes, triggered off the fluid-pressurized zone, being an indirect effect mediated by aseismic creep.

Short Bio:
I am Professor of Geophysics at the University of Nice Sophia Antipolis (France) in the Geoazur laboratory.
After a PhD in Hydromechanics (Univ. of Nice Sophia Antipolis) in 2005, I did a 2-year Post-doc at the Lawrence Berkeley National Laboratory (DOE Fellowship). In 2007, I held an Associate Professor position at the University of Nice Sophia-Antipolis in the Geoazur Earth and Planetary Sciences Laboratory. Since 2015, I am full Professor at the University of Nice Sophia Antipolis and at the Institut Universitaire de France. In 2013-2014, I was visiting Faculty for a year at CALTECH (USA) in the Tectonics Observatory (collaborations with Jean-Philippe Avouac and Pablo Ampuero). My research aims at a better understanding of the role of fluids in the mechanisms governing crustal fault and landslide dynamics, the physics of earthquakes and induced seismicity. I am interested in developing new approaches combined from geophysical observations and hydromechanical modelling for the study of coupling between fluid flow and rock deformations.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
24/05/2017 @ 12:15 room GRA330

Performance of Unreinforced Masonry Walls under Seismic Loads

Prof. Dr Michael Griffith, School of Civil, Envirnmental and Mining Engineering, University of Adelaide, Australia
Unreinforced masonry buildings are very vulnerable to earthquake loading. Such buildings can fail due to in-plane or out-of-plane failure modes. Professor Griffith’s research group is a leading group in the field of the seismic response of masonry buildings in general and the development of out-of-plane assessment methods in particular. He will give a brief overview of Adelaide University’s Structural Engineering Research Group and their research interests at the University of Adelaide before highlighting recent and ongoing research into the seismic behaviour of unreinforced masonry (URM) construction. His talk will focus primarily on:
- the seismic vulnerability of URM to out-of-plane bending and the associated local failure mechanisms;
- feasibility of near surface mounted FRP strips for seismic retrofit of URM walls;
- preliminary results of recent in-situ testing of clay brick cavity walls in ‘1960s constructed’ Adelaide houses which are being demolished for road widening projects; and
- influence of flexible floor and roof diaphrams on the seismic response of URM buildings.
Bio: Michael Griffith is Professor in the School of Civil, Environmental and Mining Engineering at the University of Adelaide. He obtained his PhD in Structural Engineering from the University of California at Berkeley (1988) after completing his BSc (Civil Eng.) and MSc (Civil Eng.) degrees at Washington State University in the US. Dr. Griffith is a member of the Standards Australia ‘Earthquake Loading Code’ committee, a Fellow of the Institution of Engineers, Australia, state committee member of the SA Structural College and Past-President and now Honorary Life Member of the Australian Earthquake Engineering Society. His main professional and research interests are in the field of earthquake engineering and structural dynamics with a particular interest in the performance of unreinforced masonry structures in earthquakes. He has co-authored over 200 research papers in the field of structural engineering and sits on the Board of Directors for the International Association of Earthquake Engineering which is based in Tokyo.
Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
02/06/2017 @ 12:15 room GCB330

RECENT ADVANCES AND FUTURE PERSPECTIVES IN COASTAL ENGINEERING AND MARINE ENERGY CONVERSION

Prof. Dr Francisco Taveira-Pinto, Faculty of Engineering, Hydraulics, Water Resources and Environment Division, Sea Energy Studies Group, University of Porto, Portugal

Abstract: The Portuguese coast is highly energetic. For that reason, engineering research is quite active in developing solutions for solving problems related with harbor safety and coastal defense, to protect assets, coastal areas and population.
Lessons from the deployment of classical protection solutions are being used to develop new soft protection techniques, by means of hydro-morphological studies as well as physical and numerical approaches. Also because of the high level of energy presented on the Portuguese coast, marine renewable energies have huge potential and can play a key role in a blue and sustainable economy. Waves and offshore wind are strategic resources for Portugal. However, their development brings relevant challenges for the conception, design, construction and operation of marine infrastructure. These challenges require innovative approaches in both physical and numerical modelling of marine hydraulics and fluid-structure interaction.
The presentation deals with some examples of challenges and opportunities related to Coastal Engineering and Marine Renewable Energy research studies, on the basis of concluded and ongoing works, carried out at the Hydraulics Laboratory of the Hydraulics, Water Resources and Environment Division (SHRHA) of the Civil Engineering Department of the Faculty of Engineering, University of Porto, Portugal.

Short bio: F. Taveira-Pinto is Full Professor of the Civil Engineering Department of the Faculty of Engineering of the University of Porto (FEUP), as well as Director of its Hydraulics Water Resources & Environment Division, Member of the board of the Hydraulics and Water Resources Institute and head of the Research Group on Sea Energy. He is currently President of the Portuguese Water Resources Association (APRH).
Formerly he was Chairman of the Coastal and Maritime Committee of the International Association for Hydro-Environment Engineering and Research (IAHR) and International Secretary of the European Union for Coastal Conservation (EUCC-The Coastal Union). He is Editor of the Journal of Integrated Coastal Zone Management, and member of the editorial board of the Journal of Coastal Conservation, Management and Planning, and of the Journal of Applied Water Engineering and Research (JAWER), as well as reviewer of several other journals.
With over 200 publications, 73 of them at international journals, his research expertise is in the field of coastal and maritime engineering. His current research focus is on physical modelling of marine infrastructure and on marine renewable energy. Within the Civil Engineering Doctoral Programme and the Integrated Master of Civil Engineering, he has supervised 7 PhD Thesis and 42 Master Thesis.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
06/08/2017 @ : room EPFL

Registration for summer school: "Open Science in Practice 2017"
"Open" is the new black. Everybody talks about it, but nobody knows what it really means.
This course will explain where open science comes from and will give an overview of latest tools researchers can use to be more efficient, more visible and more relevant in their community.
How to use 21^st century writing and publishing methods? How to best generate and share data? How to document and keep track with versions of your code? These will be some of the questions that will be answered by the panel of talented young researchers contributing to the event.
The summer school is aimed at early career researchers who are interested in learning more about what academic research will look like in the future. The core idea behind this summer school is to propose a pragmatic approach to Open Science that addresses what early career researchers care about:
- Having access to the necessary training, tools and information sources to conduct their research in an optimal way.
- Increasing the quality and visibility of their contributions to science.
- Learning best practices in the field of publication, data life cycle management, and software publishing.
- Getting credit for their work, enabling collaborations, and increasing reuse and impact.
More information about the course content can be found on the website osip2017.epfl.ch .
22/09/2017 @ 12:15 room GC C3 30

CESS talk on Durability and thermo-mechanical behavior of Fiber Reinforced Polymers (FRP) for constructions

Prof. Dr Valter Carvelli, Rofessor of Solid and Structural Mechanics, Politecnico di Milano, Italy

Fiber Reinforced Polymer (FRP) composites, in recent years, have known a widespread diffusion in several construction applications. Properties of FRP are relatively known to scientists and engineers, but there are still many concerns about their durability and their performance in real environment conditions.
The talk intends to focus on two durability related aspects: the degradation of the mechanical performance of pultruded composites adopted as cladding in building constructions; the thermo-mechanical behavior of GFRP reinforced concrete structural elements at elevated temperatures.
The first includes and extensive experimental investigation on the mechanical performance of laminates with different resin systems, and the description of an Arrhenius related methodology for the prediction of their long-term behavior.
The second topic deals with thin and thick concrete slabs reinforced with GFRP rebars exposed to elevated temperature and bending loading. Experimental measurements are considered to assess the accuracy of analytical and numerical predictions of their thermo-mechanical response.
Bio : Valter Carvelli is Professor of Solid and Structural Mechanics at Politecnico di Milano since 2007. He was Assistant Professor in the same university since 2002. He obtained the Ph.D. in Structural Mechanics at University of Bologna.
The main research interests are in the field of the mechanical behavior of composite materials reinforced with long fibers and textiles, with particular attention to their application in constructions.
He is author of more than 100 papers in peer-review international journals and international conference proceedings and author of one book. Many of his publications are dedicated to the experimental measurement and numerical prediction of the mechanical behavior of composites, with particular attention to the fatigue response and to the reinforcement of concrete structures.
He was research fellow in some Universities in Europe and Japan.
He is member of the Executive Committee of the European Society of Composite Materials. He is active in several research projects with national and European grants for the investigation and industrial application of composite materials.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
29/09/2017 @ 12:15 room GC C3 30

CESS talk on

Event organized by CESS - IIC

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
06/10/2017 @ 12:15 room GC C3 30

Research in Japan on Ultra High Performance Fibre Reinforced Cement-based Composites: Two contributions

Yuji Watanabe, Senior Research Engineer, KAJIMA Corporation, Tokyo, Japan, Dr Tohru Makita, Structural Engineer, NEXCO Central, Nagoya, Japan

Application of UHPFRC with ettringite generation system for precast member and development of cast-in- situ method presented by Yuji Watanabe
Ultra High Performance Fibre Reinforced cement-based Composites (UHPFRC), which typically has a compressive strength of at least 150 MPa and tensile strength of at least 5 MPa, brings a great deal of flexibility and additional value to design and construction, including reduction in weight and increase of long term durability of members, through such excellent material characteristics as high strength, high toughness and high durability. Especially, “AFt-UHPFRC,” an ettringite -generating type UHPFRC, is developed by using Japanese materials and original technology. UHPFRC has been used mainly for precast products manufactured in factories equipped with heat curing facilities in order to utilize its high performance. Recently, mass manufacturing and curing method of precast members assuming the large-scale application have been established in Japan. However, depending on the scale of construction and the conditions, a cast-in-situ method may be more reasonable.
In this seminar, the objectives and design by using precast UHPFRC to prestressed concrete bridge will be introduced with some applications. And reports the results of experiments and construction aiming at establishing a cast-in-situ method for the first time in Japan.

Bio : Yuji Watanabe is senior research engineer of KAJIMA Corporation. He belongs to concrete and construction materials group in Kajima Technical Research Institute (KaTRI) since 2006. He is one of the development members of AFt-UHPFRC (Japanese version of Ultra High Performance Fibre Reinforced cement-based Composites). And he was responsible for the mass production of UHPFRC slab for construction of Tokyo international airport in 2009. He is now engaged in research and development for construction and repair by using high performance concrete.

Expressway renewal project and upgrading of existing bridge decks using UHPFRC presented by Tohru Makita
Central Nippon Expressway Company Limited (NEXCO Central) operates and manages about 2,000 km expressways in the central part of Japan, 40 % of which have been placed in service for more than 40 years and average in-service period of the expressways is now about 30 years. Recent years have seen growing number of damaged and deteriorated bridges in the NEXCO Central’s expressways and the number of damaged and deteriorated bridges will get larger in the coming decades. In view of the situation, extensive renewal project of the expressways was launched in 2015, in which replacement and upgrading of bridge decks are mainly conducted.
In the expressway renewal project, upgrading of concrete bridge decks is planned to be performed by removing about 10cm deep deteriorated top surface of concrete deck and refilling it with fibre reinforced concrete (FRC) made of normal strength concrete and 1.3 vol.-% of steel fibres with length of 30 mm and diameter of 0.5 mm. However, in order to improve the load bearing capacity of bridge decks to satisfy the requirements for increased traffic load, it is often required to increase the deck thickness. By using Ultra High Performance Fibre Reinforced cement-based Composites (UHPFRC) instead of the FRC, increase of the deck thickness is avoided due to its high tensile and compressive strength. Moreover, it is not necessary to apply waterproofing membrane on top surface of bridge decks because UHPFRC has extremely low permeability and functions as protective layer.
Kajima Corporation and NEXCO Central have started a collaborative research project to develop an upgrading method of existing bridge decks using cast-in-situ UHPFRC in 2016. In this presentation, results obtained from the first stage of the research are explained briefly. The UHPFRC mix used in the research is characterised by its matrix densified by ettringite (AFt) formation; thus, it is called “AFt-UHPFRC”. The AFt-UHPFRC was originally developed for fabrication of precast members with thermal curing and hasn’t been applied to existing structures by in-situ casting. In order to understand properties of the AFt-UHPFRC, direct tensile tests and UHPFRC – concrete interfacial bond tests were conducted. The test results were analysed and the necessity to modify the AFt-UHPFRC mix composition to be suitable for upgrading of existing concrete bridge decks was identified.

Bio : Tohru Makita is structural engineer of NEXCO Central since 2002. He obtained his Bachelor’s and Master’s degree in Civil Engineering at Kyoto University and Doctor’s degree in Structural Engineering at EPFL. He is currently engaged in management of design, construction and seismic retrofitting of bridges and development and implementation of new technologies related to bridges.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
10/10/2017 @ 15:30 room STCC

"BestMile" & "EveSleep": Start-Up Success Stories

Raphael Gindrat, BestMile founder ; Kuba Wieczoreksef, Evesleep founder

You want to know how the best Swiss freelancers got to the top or the difficulties you must face while giving life to your ideas? These conferences are thought especially for you! For this big occasion, we invited some of the most innovative start-ups, awarded by the famous Top 100 Startup Award, to inspire but also to give counsels to the inventive part hiding in everyone. No matter if you already have a project of if you’re just curious about how to succeed, you should definitely join us!

BestMile : 7th best Swiss Start-Up
EveSleep: 1st best UK Start-Up

Organized by ForumEPFL
13/10/2017 @ 12:15 room GC C3 30

On the efficiency of an H-matrix based direct solver for the Boundary Element Method in 3D elastodynamics

Dr Stéphanie Chaillat, ENSTA Paristech -- CNRS, Paris, France

The main advantage of the Boundary Element Method (BEM) is that only the domain boundaries are discretized leading to a drastic reduction of the total number of degrees of freedom. In traditional BE implementation the dimensional advantage with respect to domain discretization methods is offset by the fully-populated nature of the BEM coefficient matrix. In the present work, we propose a fast method to solve the BEM system in 3-D frequency-domain elastodynamics. Using the H-matrix arithmetic and low-rank approximations (performed with Adaptive Cross Approximation), we derive a fast direct solver. We assess the numerical efficiency and accuracy on the basis of numerical results obtained for problems having known solutions. In particular, we study the efficiency of low-rank approximations when the frequency is increased.

Bio :
Dr Stéphanie Chaillat is a CNRS research scientist in the POEMS group in the Applied Mathematics department of ENSTA (Ecole Nationale Superieure des Techniques Avancées) in Palaiseau, France. Her research interests notably span boundary integral equations and boundary elements, inverse problems for elastodynamics with applications in seismology and mechanics. She graduated in 2006 as a civil engineer from Ecole Nationale des Travaux Publics de l'Etat, Lyon, France, and got her PhD at the Laboratoire de Mécanique des Solides of Ecole Polytechnique, Palaiseau France in 2008. She has received the National PhD Award from the French Computational Mechanics Association, and the European PhD Award from the European Community on Computational Methods in Applied Sciences (ECCOMAS) for her work on Fast Multipole Method for 3-D elastodynamic boundary integral equations.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
20/10/2017 @ 12:15 room GC C3 30

New directions in urban traffic control of complex transport systems

Dr Jack Haddad, Visiting Professor, Urban Transport Systems Laboratory (LUTS), EPFL, Switzerland, Assistant Professor, Transportation Engineering, Civil and Environmental Engineering Faculty, Technion – Israel

Efficient traffic control and management of large-scale transportation networks still remain a challenge both for traffic researchers and practitioners. Over decades, control strategies have been proposed and applied for isolated or coordinated intersections in arterials, while in the last decade several works have utilized the macroscopic fundamental diagram (MFD) for developing real-time control strategies to improve mobility and decrease delays in large urban networks. This seminar will focus on enhanced modeling and advanced perimeter control of uncertain MFD systems for multiple-region networks.

In the first part of this seminar, an enhanced accumulation-based model is developed by incorporating into model structure the time-delay (time-lag) effects as an important factor. The model incorporates state delay in the MFD output to improve the dynamics, i.e. representing wave propagation and travel time evolution within the region. The reference model adaptive control approach has been implemented to allow us designing distributed adaptive perimeter control laws. The numerical results demonstrate the flexibility of the distributed adaptive perimeter controllers in handling different cases and various traffic situations with state delays.

The second part of this seminar will focus on actuation failures in perimeter control. Actuation failures might cause severe system performance degradation, if the control policy is not designed to compensate these failures. The component failures are uncertain in nature, and very often it is impossible to predict in advance which component may fail during system operation, and when the component failure occurs. An adaptive fault-tolerant distributed control scheme is developed for a multi-region MFD system model. The control goal is to achieve a desired tracking performance with simultaneous (i) actuating control components failures, (ii) model parameters uncertainties, and (iii) unknown demand disturbances.

Bio : Jack Haddad is an Assistant Professor of Transportation Engineering with the Civil and Environmental Engineering faculty, the Technion – Israel Institute of Technology, and the Head of the Technion Sustainable Mobility and Robust Transportation (T-SMART) Laboratory. He received all his degrees B.Sc. (2003), M.Sc. (2006), and Ph.D. (2010) in Transportation Engineering from the Technion. He served as a post-doctoral researcher (2010-2013) at the Urban Transport Systems Laboratory (LUTS), EPFL, Switzerland. In 2008, he was a visiting Ph.D. student at the Delft Center for Systems and Control (DCSC), Delft University of Technology, the Netherlands. His current research interests include autonomous vehicles, traffic flow modeling and control, large-scale complex networks, advanced transportation systems management, and public transportation.
Dr. Haddad is a member of the IFAC Technical Committee of Transportation Systems, and a member of the Executive Council of the Israeli Association for Automatic Control (IAAC). He is an Associate Editor of the IEEE Transactions on Intelligent Transportation Systems, and the Control Engineering Practice. He also serves on the editorial board of Transportation Research Part B, Transportation Research Part C, Transportation Letters, and many international conferences. He was a recipient of the European Union Marie Curie, Career Integration Grant (CIG), ``SMART - Sustainable Mobility and Robust Transportation”, and a recipient of the Israel Science Foundation (ISF) grant with lab equipment, `` Urban traffic networks feedback control: new directions”.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
27/10/2017 @ 12:15 room GC C3 30

CESS talk on

Event organized by CESS - IIC

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
03/11/2017 @ 12:15 room GC C3 30

4D seismics in the laboratory: imaging using acoustic emission tomography

Dr Nicolas Brantut, NERC Research Fellow, Rock and Ice Physics Laboratory, Seismological Laboratory, Department of Earth Sciences, University College London, (UCL) UK

Abstract: Over the past three decades, there has been tremendous technological developments of laboratory equipment and studies using acoustic emission and ultrasonic monitoring of rock samples during deformation. Using relatively standard seismological techniques, acoustic emissions can be detected, located in space and time, and source mechanisms can be obtained. In parallel, ultrasonic velocities can be measured routinely using standard pulse-receiver techniques.

Despite these major developments, current acoustic emission and ultrasonic monitoring systems are typically used separately, and the poor spatial coverage of acoustic transducers precludes performing active 3D tomography in typical laboratory settings.

Here, I present an algorithm and software package that uses both passive acoustic emission data and active ultrasonic measurements to determine acoustic emission locations together with the 3D, anistropic P-wave structure of rock samples during deformation. The technique is analogous to local earthquake tomography, but tailored to the specificities of small scale laboratory tests. The fast marching method is employed to compute the forward problem. The acoustic emission locations and the anisotropic P-wave field are jointly inverted using the Quasi-Newton method. I will present benchmark tests, as well as a real-life example showing the propagation of a compaction front in a porous sandstone.

Bio: Nicolas Brantut has been working as a NERC Research Fellow at University College London (where he also holds a proleptic lectureship appointment) since October 2013. He obtained his PhD in 2010 from the École Normale Supérieure and the Institut de Physique du Globe, Paris, working under the supervision of Pr. Yves Guéguen and Dr. Alexandre Schubnel on thermo-hydro-mechanical and chemical coupling process during earthquakes. He served as a post-doctoral research associate in the Rock and Ice Physics Laboratory at UCL, under the supervision of Pr. Philip Meredith, between 2010 and 2013. His research interests are in fault and earthquake mechanics, rock physics, and seismology. He uses both experimental approaches with high pressure rock deformation experiments and theoretical approaches with a strong emphasis on micro-mechanical modelling.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
10/11/2017 @ 12:15 room GC C3 30

Slow and Fast Slip Dynamics From Fracture Networks

Dr Harsha S. Bhat, CNRS scientist, Laboratoire de Géologie, ENS, Paris, France

Abstract : Active faults release elastic strain energy via a whole continuum of modes of slip, ranging from devastating earthquakes to Slow Slip Events and persistent creep. Understanding the mechanisms controlling the occurrence of rapid, dynamic slip radiating seismic waves (i.e. earthquakes) or slow, silent slip (i.e. SSEs) is a fundamental point in the estimation of seismic hazard along subduction zones. On top of showing slower rupture propagation velocity than earthquakes, SSEs exhibit different scaling relationships, which could reflect either different physical mechanisms or an intriguing lack of observations. Like earthquakes, SSEs are bound to occur along unstable portions of active faults, raising the question of the physical control of the mode of slip (seismic or aseismic) along these sections. Here, we use the numerical implementation of a simple rate-weakening fault model to explain the spontaneous occurrence, the characteristics and the scaling relationship of SSEs and earthquakes. Our unified framework only accounts for the geometrical complexity of fault networks and associated stress perturbations, leading to the emergence of all modes of slip from earthquakes to SSEs without appealing to complex rheologies or mechanisms. Our model helps resolving many of the existing paradoxes between observations and physical models of earthquakes and SSEs and reproduces all episodes of fault slip in nature, including those unexplained yet.

Bio : Dr Harsha Bhat is a CNRS scientist at the Laboratoire de Géologie in Ecole Normale Supérieure in Paris. He received his PhD in mechanics from Harvard University, USA in 2007, and was a post-doctoral associate at University of Southern California and Caltech prior to moving to Paris in 2012. His research interests are related to fracture mechanics, elasto-dynamics, geomechanics and in particular the mechanics of faulting, especially the importance of fault zone geometry, and off-fault damage during earthquakes.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
17/11/2017 @ 12:15 room GC C3 30

Coseismic damage near active faults : a laboratory perspective

Prof. Dr Mai Linh Doan, ISTerre, University of Grenoble, France

Abstract : Earthquakes are generated by the fast propagation of slip along active faults.The faults are not a pure sharp discontinuity but are borded by a damage zone, that witnessed the history of the fault growth, tectonics loading and previous earthquakes. The latter is of great interest for the study of previous earthquakes but it needs to be discriminated from static damage. That’s why we pioneered a series of experiments to find markers of dynamic damage.
To do so, several rocks were loaded with Split Hopkinson Pressure Bars. We found that at strain rate, crystalline rocks tend to fragment in finely grained rocks but the accumulated strain is so small that the initial rock structure is preserved. This is similar to the pulverised rocks found in the field.The high strain needed to create this pervasive diffuse damage suggest an exceptionally high strain rate shaking, which is important for seismic hazard assessment. By repeating loading, a similar phenomenon occurs, but the threshold is only reduced by half.
Besides being promising for paleoseismic studies, the study of dynamic damage reveals appealing properties for the coseismic damaged rocks, with a sharply reduced sonic velocity and a strongly enhanced permeability, which can strongly affect the hydromechanical properties of active faults.

Bio : Mai-Linh Doan is assistant professor at ISTerre, an Earth Sciences laboratory of Université Grenoble-Alpes. She majored in physics at ENS Paris and then switched to geophysics to works on the mechanics of active faults (PhD in IPG-Paris and postdoctoral stay at UCLA and UCSC). She combines in situ observation of the hydromechanics of fault zone through scientific drilling and borehole geophysics, with laboratory rock mechanics experiments. Especially, she works to identify how the dynamic loading of earthquakes can produce markers of dynamic damage that can be used as marker of previous large earthquakes.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
24/11/2017 @ 12:15 room AAC 0 08

Hazard, Ageing, Probability and Why Infrastructure Needs to be Designed for Performance

Prof. Dr Dimitrios Vamvatsikos, Assistant Professor, Institute of Steel Structures, School of Civil Engineering, National Technical University of Athens, Greece

Abstract : A civil engineering project is a difficult battle with nature. We are fighting against uncertain loads, materials and ageing under changing climatic conditions, using imperfect analysis/modeling tools, and under severe financial, operational and architectural constraints. Our staunchest ally in this endeavor seems to be the design code that offers some standardization to the design process and essentially represents a social contract on what constitutes an acceptable structure. At the same time, though, the design code may also obscure some fundamental principles that one seems to apply when making everyday financial decisions, like buying a car, a smartphone or a computer, but not necessarily when building vastly more expensive infrastructure (ports, bridges, pipelines, etc.). In a market saturated with competing consumer products that cater to every user need and purse size, it seems that very few structural solutions are made available to a risk-conscious future building owner. In the course of the presentation we shall argue the case for designing to cater to a user’s needs, going beyond the structural code to achieve sui generis structures with the required performance.

Bio: Dr. Vamvatsikos studied civil engineering at the National Technical University of Athens (Diploma, 1997) and at Stanford University (MSc 1998, PhD 2002). Since 2011 he has joined the Institute of Steel Structures at NTUA, where he holds the position of Assistant Professor specializing in the static and dynamic analysis of steel structures. His research interests are focused on integrating structural modeling, computational techniques, probabilistic concepts and experimental results into a coherent framework for the performance evaluation of structures and infrastructure under man-made and natural hazards. His seminal work in risk assessment via Incremental Dynamic Analysis has received wide attention leading to more than 2000 citations. He has co-operated with leading structural engineering firms (ARUP, Halcrow/CH2M), the oil&gas industry (Shell, ExxonMobil), catastrophe risk modelers (AIR Worldwide, RED Srl), and insurance/reinsurance companies (AXA Insurance), while his research has been funded by the Applied Technology Council, the Federal Emergency Management Agency, the US National Institute of Standards and Technology and the European Commission. He is a long-time collaborator of the Global Earthquake Model (GEM) Foundation and has contributed to the GEM vulnerability assessment guidelines and the Risk Modeler’s Toolkit for OpenQuake.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
01/12/2017 @ 12:15 room GC C3 30

Applications of subdomain coupling methods to structural dynamics and multiphysics

Prof. Dr Michael Brun, INSA-Lyon, Lyon, France

Abstract: The increasing complexity of numerical models for engineering systems, taking into account ever finer mesh, accurate material models and multiphysics phenomena occurring at very different space and time scales, boosted the development of partitioning approaches. In the field of structural dynamics, the main interest of the partitioning approach is to increase computational efficiency by using different time integrators with their own time step, depending on the non-overlapping subdomains composing the global mesh. First, subdomain coupling methods have been set up, following an energy-based argument, leading to the proposition of Hybrid Asynchronous Time Integrator (HATI), stable and second or first order accurate depending on the ratio between the time scales. A large variety of applications of the HATI is then presented in the fields of structural dynamics and multiphysics: reinforced concrete subjected to earthquake or blast loading, crane bridge under earthquake loading experiencing non smooth dynamics phenomena (large number of impacts), soil structure interaction problem by introducing Perfectly Matched Layers (PML) in the HATI framework for reproducing unbounded domains, coupling a wave propagation software in soils, based on Spectral Element Method (SEM), with a FEM software for the structure, fluid structure interaction problem with the coupling of a water jet, modeled with Smooth Particle Hydrodynamics (SPH) method, impacting a FEM modeled hydroelectric turbine’s steel bucket. The last application developed within LSMS laboratory, EPFL, concerns the simulation of a sudden rock sliding contact along a seismic fault, involving HATI, contact and friction algorithms as well as PML.

Bio: Dr Michael BRUN is an associate professor at INSA-Lyon, in civil engineering laboratory GEOMAS. His research interests are focused on computational science in dynamics, applied to civil engineering structures and multiphysics coupling problems such as soil-structure and fluid-structure interactions. He got his PhD at INSA-Lyon in 2002 and worked during three years as an engineer in a private company (EC2-Modélisation, Lyon) specialized in simulations and software development. Since 2005, he has joined INSA-Lyon where he holds the position of Associate Professor, teaching continuum mechanics, strength of materials and numerical methods in the civil engineering and urban planning Department of INSA-Lyon.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
08/12/2017 @ 12:15 room GC C3 30

Strength of Adhesive Contacts: Experiment and numerical simulation

Prof. Dr Valentin L. Popov, Technische Universität Berlin, Germany

Valentin L. Popov, Roman Pohrt, Qiang Li, Technische Universität Berlin, Germany

Abstract : The strength of an adhesive contact between two bodies can strongly depend on the macroscopic and microscopic shape of the surfaces. In the past, the influence of roughness has been investigated thoroughly. However, even in the presence of perfectly smooth surfaces, geometry can come into play in form of the macroscopic shape of the contacting region. Here we present numerical and experimental results for contacts of rigid punches with flat but oddly shaped face contacting a soft, adhesive counterpart. When it is carefully pulled off, we find that in contrast to circular shapes, detachment occurs not instantaneously but detachment fronts start at pointed corners and travel inwards, until the final configuration is reached which for macroscopically isotropic shapes is almost circular. For elongated indenters, the final shape resembles the original one with rounded corners. We describe the influence of the shape of the stamp both experimentally and numerically.
Numerical simulations are performed using a new formulation of the Boundary Element Method for simulation of adhesive contacts suggested by Pohrt and Popov. It is based on a local, mesh dependent detachment criterion which is derived from the Griffith principle of balance of released elastic energy and the work of adhesion. The validation of the suggested method is made both by comparison with known analytical solutions and with experiments. The method is applied for simulating the detachment of flat-ended indenters with square, triangle or rectangular shape of cross-section as well as shapes with various kinds of faults and to “brushes”. The method is extended for describing power-law gradient media.
Additionally, we discuss some implications of this work for simulations of material behavior, in particular adhesive wear.

Bio : Valentin L. Popov is full professor at the Berlin University of Technology, studied physics (1976-1982) and obtained his doctorate in 1985 from the Moscow State Lomonosov University. He worked at the Institute of Strength Physics of the Russian Academy of Sciences. After a guest professorship in the field of theoretical physics at the University of Paderborn (Germany) from 1999 to 2002, he has headed the department of System Dynamics and the Physics of Friction of the Institute of Mechanics at the Berlin University of Technology. His areas of interest include tribology, nanotribology, tribology at low temperatures, biotribology, the influence of friction through ultrasound, numerical simulation of frictional processes, research regarding earthquakes, as well as topics related to materials science such as the mechanics of elastoplastic media with microstructures, strength of metals and alloys, and shape memory alloys. He has published over 100 papers in leading international journals during the past 5 years. He is the author of the book "Contact Mechanics and Friction: Physical principles and applications" which appeared in three German, two English, Chinese, and Russian editions and co-author of the book on “Method of dimensionality Reduction in Contact Mechanics and Friction” which appeared in German, English and Chinese editions. He is the joint editor of international journals and regularly organizes international conferences and workshops over diverse tribological themes. He is a member of the Scientific Council of the German Tribological Society. He has intensively collaborated with many industrial corporations and possesses experience in implementing the results of scientific research in industrial applications.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
15/12/2017 @ 12:15 room GC C3 30

CESS talk on

Event organized by CESS - IIC

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
23/02/2018 @ 12:15 room GC B3 30

CESS Talk on

Event to be organized by IIC

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
02/03/2018 @ 12:15 room GC B3 30

Open issues on seismic assessment of existing masonry buildings: linear vs nonlinear, static vs dynamic, local vs global approaches

Prof. Dr Sergio Lagomarsino, Full Professor of Structural Engineering, Department of Civil, Environmental and Chemical Engineering, Polytechnic School
DICCA - University of Genoa, Italy

ABSTRACT: The seismic assessment of existing masonry buildings is a difficult task due to the complexity of reliable models, particularly in the case of older non-engineered ones. The qualitative approach is a essential element of knowledge for the interpretation of the seismic behaviour but cannot replace a quantitative security check. As-built information, based on historical notes on transformation and the survey of constructive details, together with the results of investigation on material properties, are the basis for the choice and calibration of the structural models with which to carry out the verifications. Modelling and analysis procedures should be as accurate as possible in catching the actual seismic response, but at the same time robust and practice-oriented. This keynote lecture offers a general framework for the assessment of existing masonry buildings (in unreinforced, reinforced and confined masonry) and is focused on distinctive features and open issues in this field. The assessment is based on the evaluation of the global seismic response, relying on the in-plane resistance of masonry walls, and the verification of possible local mechanisms, related to out-of-plane behaviour of walls substructures. For the global analysis, it is suggested: a) a modelling approach that takes into account the diaphragms stiffness; b) different failure criteria for masonry piers for regular and irregular masonry; c) specific failure criteria for the spandrels; d) a combination of global and local checks for the definition of limit states. For local mechanisms, the following are proposed: a) the use of equilibrium limit analysis, considering the evolution of rigid block mechanisms, for the evaluation of the horizontal seismic strength and the ultimate displacement capacity; b) a new formulation for the floor spectra, with an accurate estimate of the displacement demand on these mechanisms at different levels of the building.

Bio : Sergio Lagomarsino is professor of Structural Engineering at the University of Genoa, since 2000. Author of many journals papers and chapters of scientific books on the topics: seismic assessment of existing structures, nonlinear modelling of masonry, preservation of monumental buildings and historical centres, seismic risk and vulnerability analysis (in Scopus: h-index 24, 78 articles and 1791 citations). He has coordinated the European project PERPETUATE on the seismic assessment and protection of cultural heritage assets, as well as many other national projects. He sits on the editorial boards of “International Journal of Architectural Heritage" and of “Earthquakes and Structures”. He has served in the drafting panels of the Italian seismic code and the Italian Guidelines for cultural heritage in seismic areas. At present, he is member of the Project Team 3 that is working on the revision of Eurocode 8, Part 3: “Assessment and retrofitting of buildings”. He developed the software program TREMURI, for the nonlinear seismic analysis of masonry buildings, and the Italian survey form for post-earthquake damage assessment of churches.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
09/03/2018 @ 12:15 room GC B3 30

The variational approach to fracture: formulation, general properties and examples

Prof. Dr Jean-Jacques Marigo, Ecole Polytechnique, Palaiseau, Île-de-France, France

Abstract : The lecture is devoted to gradient damage models which allow us to describe all the process of degradation of a body including the nucleation of cracks and their propagation. The construction of such model follows the variational approach to fracture [2] and proceeds into two stages: (1)
definition of the energy; (2) formulation of the damage evolution problem. The total energy of the body is defined in terms of the state variables which are the displacement field and the damage field in the case of quasi-brittle materials [5], whereas they contain also the plastic strain field in the case of ductile materials [1]. That energy contains in particular gradient damage terms in order to avoid too strong damage localizations. The formulation of the damage evolution problem then based on the concepts of irreversibility, stability and energy balance, as well inquasi-static as in dynamic [4]. That allows us to construct homogeneous as well as localized damage solutions in a closed form and to illustrate the concepts of loss of stability, of scale effects, of damage localization, and of structural failure. Moreover, the variational formulation leads to a natural numerical method based on an alternate minimization algorithm. Several numerical examples will illustrate the ability of this approach to account for all the process of fracture including a 3D thermal shock problem where the crack evolution is very complex [3].

References
[1] R. Alessi, J.-J. Marigo, and S. Vidoli. Gradient damage models coupled with plasticity: variational formulation and main properties. Mechanics of Materials, 80:351–367, 2015.
[2] B. Bourdin, G. A. Francfort, and J.-J. Marigo. The variational approach to fracture. J. Elasticity, 91(1–3):5–148, 2008.
[3] B. Bourdin, J.-J. Marigo, C. Maurini, and P. Sicsic. Morphogenesis and propagation of complex cracks induced by thermal shocks. Phys. Rev. Lett., 112(1):014301, 2014.
[4] T. Li, J. J. Marigo, D. Guilbaud, and S. Potapov. Numerical investigation of dynamic brittle fracture via gradient damage models. Advanced Modeling and Simulation in Engineering Sciences, DOI: 10.1186/s40323-016-0080-x:3–26, 2016.
[5] K. Pham, H. Amor, J.-J. Marigo, and C. Maurini. Gradient damage models and their use to approximate brittle fracture. International Journal of Damage Mechanics, 20(4):618–652, 2011

Bio : Jean-Jacques Marigo obtained his PhD in Mechanics from the University Pierre and Marie Curie (Paris, France). He is currently a full-time professor in the mechanics department at the Ecole Polytechnique (Palaiseau, Île-de-France, France). He has received the Prix Paul Doistau-Emile Blutet in 2002 from the l'Académie des Sciences (France) and the Tullio Levi Civita International Prize in Mechanics and Applied Mathematics in 2011 by the Tullio Levi Civita Foundation (Italy). Since 2009, Prof. Marigo is an associated editor of the Journal of Elasticity.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
23/03/2018 @ 12:15 room GC B3 30

Seismic protection of new and existing structures exploiting nonlinear soil–foundation response

Prof. Dr Ioannis Anastasopoulos, Chair of Geotechnical Engineering, ETH Zurich, Switzerland

Abstract: According to current seismic codes, the foundation soil is not allowed to fully mobilize its strength, and plastic deformation is restricted to above-ground structural members. Capacity design is applied to the foundation guiding failure to the superstructure, thus prohibiting mobilization of soil bearing capacity. However, a significant body of evidence suggests that allowing strongly nonlinear foundation response may be advantageous. The lecture will introduce an alternative seismic design philosophy termed rocking isolation, in which soil yielding is used as a “fuse”. According to such a scheme, the foundation is intentionally under-designed to uplift and fully mobilize its bearing capacity, limiting the inertia transmitted onto the superstructure. To unravel the effectiveness of rocking isolation, a bridge pier is used as an illustrative example. A conventionally designed system is compared to a rocking–isolated alternative. Their seismic performance is explored analytically, through nonlinear finite element analyses, and experimentally, through shaking table and centrifuge model testing. A similar comparison is performed for an existing structure. Finally, novel concepts are introduced, aiming to minimize permanent rotations and settlements.

Short bio: Ioannis Anastasopoulos has been Full Professor of Geotechnical Engineering at ETH Zurich since 2016. He specializes in geotechnical earthquake engineering and soil–structure interaction, combining numerical with experimental methods. His academic degrees include a PhD from the National Technical University of Athens (NTUA), an MSc from Purdue University, and a Civil Engineering Diploma from NTUA. His research interests include the development of innovative seismic hazard mitigation techniques, faulting and its effects on infrastructure, site effects and slope stabilization, railway systems and vehicle–track interaction, seismic response of monuments, offshore geotechnics, and earthquake crisis management systems. He has been involved as a consultant in a variety of projects of significance in Europe, but also in the US and the Middle East. His consulting work ranges from special seismic design of bridges, buildings, retaining walls, metro stations and tunnels, to harbour quay walls, and special design against faulting–induced deformation applying the methods he has developed. He currently serves as Associate Editor of Frontiers in Earthquake Engineering, and has sat on the panel of Géotechnique and of the ICE Geotechnical Engineering Journal. He is the inaugural recipient of the Young Researcher Award of the ISSMGE in Geotechnical Earthquake Engineering, and winner of the 2012 Shamsher Prakash Research Award.

Organized by Prof. Brice Lecamipon et Prof. Katrin Beyer
06/04/2018 @ 12:15 room GC B3 30

New systems of precast bridge decks made with ultra-high performance fiber reinforced concretes

Prof. Dr Jean-Philippe Charron, Full Professor in Civil Engineering, Department of Civil, Geological and Mining Engineering, Polytechnique Montreal

Abstract : The presentation will focus on the development of various precast bridge slabs including ultra-high performances fiber reinforced concrete (UHPFRC), and a UHPFRC field-cast connection adapted for these precast slabs. Phase 1 of the project provided three innovative bridge slab designs: a reference slab made of high performances concrete (HPC), a hybrid slab incorporating high and ultra-high performances fiber reinforced concrete (HPFRC and UHPFRC), and a UHPFRC slab. Test conducted in laboratory demonstrated that slabs made with UHPFRC fulfilled easily requirements of crack openings and ultimate strength specified in the Canadian Bridge Code. The UHPFRC field-cast connection developed in Phase 2 of the project was combined with precast slabs developed in Phase 1 and tested in laboratory. The tests confirmed that HPC slabs linked with the UHPFRC connection provided similar maximum crack openings, stiffness and ultimate strength as the equivalent cast-in-place HPC slab. Moreover, utilization of the UHPFRC connection between precast hybrid slabs provided smaller crack width and superior ultimate strength than specifications of the Canadian Bridge Code. Parametric numerical studies showed the improved mechanical performance of precast deck including UHPFRC component detailed previously. The Isabey-Darnley pedestrian bridge build in 2016 with UHPFRC precast bridge slabs and field-cast joints developed in this project will be described.

Bio : Jean-Philippe Charron is Full Professor at the Department of Civil, Geological and Mining Engineering of Polytechnique Montreal and head of the Group for Research in Structural Engineering. He completed a PhD at Laval University (Canada) on early-age behavior of concrete and cracking mitigation in 2002 and a post-doc at EPFL (Switzerland) on the rehabilitation of infrastructures with ultra-high performance fiber reinforced concretes (UHPFRC) in 2004. Since 2007, he is leading industrial research projects on the development of new bridge components and bridge repairs with high and ultra-high performance fiber reinforced concretes (HPFRC and UHPFRC) funded by the Natural Sciences and Engineering Research Council of Canada, major bridge owners and construction companies. He is member of ACI Committees 239 on UHPFRC and 544 on FRC, he is also involved in the development of the Canadian Bridge Design Code. His research interests include development and characterization of fiber reinforced concretes (FRC), design and rehabilitation of bridges with FRC, and durability of concretes under loads.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Katrin Beyer
13/04/2018 @ 12:15 room GC B3 30

Slow and Fast Slip Dynamics From Fracture Networks

Dr Harsha S. Bhat, CNRS scientist, Laboratoire de Géologie, ENS, Paris, France

Abstract : Active faults release elastic strain energy via a whole continuum of modes of slip, ranging from devastating earthquakes to Slow Slip Events and persistent creep. Understanding the mechanisms controlling the occurrence of rapid, dynamic slip radiating seismic waves (i.e. earthquakes) or slow, silent slip (i.e. SSEs) is a fundamental point in the estimation of seismic hazard along subduction zones. On top of showing slower rupture propagation velocity than earthquakes, SSEs exhibit different scaling relationships, which could reflect either different physical mechanisms or an intriguing lack of observations. Like earthquakes, SSEs are bound to occur along unstable portions of active faults, raising the question of the physical control of the mode of slip (seismic or aseismic) along these sections. Here, we use the numerical implementation of a simple rate-weakening fault model to explain the spontaneous occurrence, the characteristics and the scaling relationship of SSEs and earthquakes. Our unified framework only accounts for the geometrical complexity of fault networks and associated stress perturbations, leading to the emergence of all modes of slip from earthquakes to SSEs without appealing to complex rheologies or mechanisms. Our model helps resolving many of the existing paradoxes between observations and physical models of earthquakes and SSEs and reproduces all episodes of fault slip in nature, including those unexplained yet.

Bio : Dr Harsha Bhat is a CNRS scientist at the Laboratoire de Géologie in Ecole Normale Supérieure in Paris. He received his PhD in mechanics from Harvard University, USA in 2007, and was a post-doctoral associate at University of Southern California and Caltech prior to moving to Paris in 2012. His research interests are related to fracture mechanics, elasto-dynamics, geomechanics and in particular the mechanics of faulting, especially the importance of fault zone geometry, and off-fault damage during earthquakes.

Organized by Prof. Dr Brice Lecampion, GEL
20/04/2018 @ 12:15 room GC B3 30

Composite solutions made with rubberized concrete From experimental testing to seismic performance assessment

Prof. Dr Miguel Castro, Assistant Professor, Civil Engineering Dept, Faculty of Engineering, University of Porto, Portugal

The reuse of solid waste is now a subject of critical importance in developed societies. Scrap tyres are just one example of solid waste demanding special attention. It is estimated that about 300 million scrap tyres reach their end-of-life each year in the European Union. One of the possible ways of using recycled rubber from car tyres is through its application in the development of new construction materials. In this seminar, a research study will be presented that aimed at evaluating the feasibility of using rubberized concrete in composite steel-concrete tubular solutions for seismic resistance. The research comprised an experimental campaign carried out on concrete-filled steel tubular (CFST) elements made with conventional and rubberized concrete, subjected to monotonic and cyclic bending conditions. The test results revealed that the hysteretic flexural behaviour of CFSTs is practically insensitive to the type of concrete. The results were then employed on the calibration of 3D detailed FE models developed in ABAQUS. Parametric studies were performed aiming at i) the characterization of the effects of multi-axial stress states on the behaviour of concrete and steel materials and at ii) the evaluation of the cross-section slenderness limits prescribed in Eurocode 8 and AISC 341 provisions. The results of these studies led to the proposal of an improved procedure for the evaluation of the cross-sectional resistance of CFST elements subjected to combined compression with bending. The presentation will conclude with a comparative study of the seismic performance of composite moment-resisting frame buildings made with CFST elements and conventional steel moment frame buildings. The results obtained indicate that, in addition to contribute to a more sustainable environment, composite lateral loading resisting systems made with rubberized concrete are an attractive solution for structures located in high seismicity regions.

Bio : José Miguel Castro is an Assistant Professor at the Civil Engineering Department of the Faculty of Engineering of the University of Porto. He graduated in civil engineering from the University of Porto in 1994 and concluded an MSc in Structural Steel Design at Imperial College London in 2000. He obtained a PhD in Civil Engineering from Imperial College London in 2006. Miguel is an expert in steel and composite structures subjected to earthquake loading conditions and has been actively involved in several national and European research projects. He is a full member of Technical Committee 13 on Seismic Design of the European Convention for Constructional Steelwork (ECCS) and is also a member of CEN/TEC250/WG2 that is working towards the development of the new version of Eurocode 8, the European seismic code. His current research interests are on the development of novel seismic design methodologies for steel structures as well as on the collapse and seismic risk assessment of new and existing steel buildings.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
27/04/2018 @ 12:15 room GC B3 30

Dynamic Discretization Discovery

Dr Michael Hewitt, Associate Professor, Director, Information Systems and Supply Chain Management Dept, Quinlan School of Business, Loyola University, Chicago, USA

Time-expanded networks are a useful tool from both modeling and computational perspectives. In terms of modeling, they enable a natural method for representing decisions that have both a geographic and temporal component. In terms of computation, they yield stronger integer programming formulations than those that represent time with continuous variables, which in turn require less time to solve. A drawback to the use of time-expanded networks is that they require time to be discretized. While finer discretizations yield more precise representations of time, they also lead to larger optimization models which may then require too much time to solve. However, this trade-off is primarily a function of choosing a discretization in a static and a priori manner. In this talk, we will present a method that generates time expanded networks in an iterative and dynamic fashion in the context of solving an optimization model that prescribe actions in both time and space. We will illustrate the use of this method on two classical problems seen in transportation and logistics: (1) the Service Network Design problem, which can be used to model the routing of goods between cities, and, (2) the Traveling Salesman Problem with Time Windows, which can be used to model the routing of goods within a city.

Bio:
Dr. Hewitt is an Associate Professor in the Information Systems and Supply Chain Management Department in the Quinlan School of Business at Loyola University Chicago, where he also serves as the Director of graduate programs in Supply Chain Management. His research includes developing quantitative models of decisions found in the transportation and supply chain management domains, particularly in freight transportation and home delivery. His work has assisted the decision-making of companies such as Exxon Mobil, Saia Motor Freight, and Yellow Roadway. He has expanded his area of expertise to include workforce planning, including working on multi-disciplinary projects at the intersection of operations management and cognitive psychology. His research has been funded by agencies such as the National Science Foundation, the Material Handling Institute, and the New York State Health Foundation. Before entering the PhD program at Georgia Tech, Dr. Hewitt worked as a software engineer, contributing to the development of software to support consumer set-top boxes and LED signs in mass transit stations.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
04/05/2018 @ 12:15 room GC B3 30

CESS Talk on

Laurent Brochard

Event to be organized by IIC

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
15/05/2018 @ 12:15 room MED 0 1418

MechE Colloquium: Accessing through Keyholes – Continuum Robots at Small Scales

Prof. Jessica Burgner-Kahrs, Faculty of Mechanical Engineering, Leibniz Universität Hannover

Abstract:
Continuum robots are inspired by nature, in particular by elephant trunks, anteater tongues, or tentacles. As they are not composed of discrete joints or rigid links, they differ substantially from conventional robots. Their structure is composed of flexible, elastic, or soft materials such that complex bending and twisting motions can be achieved. Thus, continuum robots can be deployed in tortuous environments and used for dexterous manipulation tasks in constrained environments. The high scalability and miniaturization potential allow for numerous applications, e.g. minimally invasive surgery through natural orifices or in situ inspection of capital goods such as aircraft engines. The presentation will give an overview of continuum robot designs and touch upon fundamentals in kinematic modeling, planning, and control. Open research questions and cross-disciplinary challenges are discussed.

Bio:
Prof. Jessica Burgner-Kahrs is heading the Laboratory for Continuum Robotics at the Leibniz Universität Hannover since November 2015. Prof. Burgner-Kahrs graduated from Universität Karlsruhe (TH), Germany in computer science and got her Ph.D. at Karlsruhe Institute of Technology (KIT), Germany. Before she started at Leibniz Universität Hannover in 2013, she was Research Associate at Vanderbilt University, USA for two years.

Her research focus lies on continuum robotics and in particular on their design, modelling, planning, and control as well as human-robot interaction. In 2015, she was awarded the Heinz Maier-Leibnitz Prize, the Lower Saxony Science Award in the category Young Researcher, and entitles Young Researcher of the Year 2015 in Germany. The Berlin-Brandenburg Academy of Sciences awarded her the Engineering Science Prize in 2016. She was also elected as one of the Top 40 under 40 in the category Science and Society in 2015, 2016, and 2017 by the business magazine Capital.

Organized by MechE Colloquium
18/05/2018 @ 12:15 room GC B3 30

Structures as Sensors: Using Structures to Indirectly Monitor Humans and Surroundings

Prof. Dr Hae Young Noh, Assistant Professor Dept. of Civil & Environmental Engineering and courtesy assistant professor Dept. of Electrical & Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA

This talk introduces “structures as sensors” for the indirect monitoring of cyber-physical-human systems by sensing and analyzing their noisy physical structural responses. Smart structures are designed to sense, understand, and respond to various situations involving the structure itself, the humans within, and the surrounding environment. Traditional direct monitoring approaches using dedicated sensors often result in dense and heterogeneous sensing systems that are difficult to install and maintain in large-scale structures. The conditions of the structure itself, the environment around, and the activities of users within all have a direct impact on the physical responses of the structure. For example, human walking induces building floor vibrations, uneven road surfaces and bridge settlement change vehicle motions, etc.
This talk focuses on my “structures as sensors” approach that utilizes the structure as a sensing medium to indirectly infer multiple types of hidden information relating to the structure (e.g. the users and the surrounding). By using the same set of sensors for multiple types of information, and because of wave propagation characteristics, this approach significantly reduces the number and type of sensors needed to install and maintain. Challenges lie, however, in creating robust inference models for analyzing convoluted noisy structural response data (e.g., a mixture of building responses due to human activities, outside traffic, seismic events). To this end, I developed physics-guided data analytics approaches that combine statistical signal processing and machine learning with physical principles (e.g., wave propagation, human motions, structural dynamics, etc.). Specifically, I present two projects as examples of this approach; 1) Vehicles as Sensors: indirect infrastructure health monitoring through vehicle responses; and 2) Buildings as Sensors: occupant tracking and characterization through footstep-induced building vibrations. I will also present results from the real-world experiments, including our 3-year railway and eldercare center deployments.

Bio: Hae Young Noh is an assistant professor in the Dept. of Civil & Environmental Engineering and a courtesy assistant professor in the Dept. of Electrical & Computer Engineering at Carnegie Mellon University. Her research focuses on indirect sensing and physics-guided data analytics to enable low-cost and non-intrusive monitoring of cyber-physical-human systems. The result of her work has been deployed in a number of real-world applications from trains, to the Amish community, to eldercare centers, to pig farms. She received her Ph.D. and M.S. degrees in Civil and Environmental Engineering and the second M.S. degree in Electrical Engineering at Stanford University. She earned her B.S. degree in Mechanical and Aerospace Engineering at Cornell University. She received a number of awards, including the Google Faculty Research Awards in 2013 and 2016, the Dean’s Early Career Fellowship in 2018, and the National Science Foundation CAREER award in 2017.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
25/05/2018 @ 12:15 room GC B3 30

Cost-effective Steel Seismic Force Resisting Systems for Enhanced Response to Earthquakes

Prof. Dr Robert Tremblay, Département des Génies Civil, Ecole Polytechnique de Montréal, Canada

abstract : This presentation will introduce structural steel seismic force resisting systems that have been proposed to enhance the response of structures to earthquakes. The focus will be on braced frames used for building structures. The eccentrically braced frame system with replaceable ductile links will be introduced as an example where a minor modification can reduce fabrication costs, improve the seismic response and help post-earthquake recovery. Concentrically braced steel frames modified to exhibit self-centering response and eliminate structural damage by using either special brace members, rocking response or a combination thereof are then discussed. Controlled rocking response generally result in reduced seismic induced force demands on the structure and its foundations compared conventional designs. Such reductions can be significant and can be achieved at low cost for short-period, low-rise buildings responding essentially in their fundamental mode, which makes the concept attractive for the seismic retrofit of seismically deficient building structures. Single-storey steel buildings with large foot prints that are used for commercial and light industrial applications or sport facilities represent a large portion of the building stock in Canada. Seismic resistance for these structures is typically obtained using an horizontal roof diaphragm acting with vertical braced frames. Ductile brace fuses and rocking braced frames will be presented as options that can be implemented to enhance the response and reduce construction costs. Lastly, the presentation will discuss structural systems that are being investigated to achieve stable inelastic response for tall braced frames. These will include frames equipped with segmental elastic trusses and frames that are designed to exhibit post-yielding lateral stiffness.

Bio : Robert Tremblay is Professor of Structural Engineering at Polytechnique Montreal, Canada. He received his Bachelor (1978) and Master (1988) degrees from Université Laval and completed his Ph.D. in 1994 at the University of British Columbia in Vancouver. Before undertaking his doctoral studies, Prof. Tremblay worked for 10 years in the industry. He held a 14-year Canadian Research Chair in earthquake engineering between 2003 and 2017. His current research work is mainly directed towards the seismic design and response of steel structures. He is a member of the Standing Committee on Earthquake Design for the National Building Code of Canada, the CSA-S16 Technical Committee on Steel Structures for Buildings, the CSA S6 Technical Sub-Committee on Seismic Design of Bridge Structures, the AISC Task Committee 9 on seismic design of steel structures and the AISC Adhoc Task Group on Non-Building Structures and Industrial Buildings.

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
01/06/2018 @ 08:30 room DIA 004

PhD seminar “From research to publication” 3/4

EPFL Library Teaching team

Take part in the next EPFL Library training seminar for PhDs and get an overview of all steps you will go through from literature search to the publication of your outputs. Gather practical tools and tips to become more efficient and avoid common pitfalls.

Module 3: Smart publishing
Understand how scientific publishing works: choose a publishing model (traditional, Green/Gold Open Access, hybrid), submission, peer-reviewing process and dissemination of the paper. Read some publishers contracts and understand their stakes.
I register for next session on June 1 (8:30-12:30)

Organized by EPFL Library
01/06/2018 @ 12:15 room GC B3 30

CESS Talk on

Event to be organized by IIC

Organized by Prof. Brice Lecampion & Prof. Katrin Beyer
04/06/2018 @ : room Swiss Tech Convention Center

2018 IEEE Data Science Workshop

Keynote speakers Dr. Lisa Amini IBM Research, Dr. Surajit Chaudhuri Microsoft Research, Prof. Volker Markl, Technische Universität Berlin, Prof. Gil McVean Oxford University, Prof. Victoria Stodden UIUC

The 2018 IEEE Data Science Workshop is a new workshop that aims to bring together researchers in academia and industry to share the most recent and exciting advances in data science theory and applications. In particular, the event will gather researchers and practitioners in various academic disciplines of data science, including signal processing, statistics, machine learning, data mining and computer science, along with experts in academic and industrial domains, such as personalized health and medicine, earth and environmental science, applied physics, finance and economics, intelligent manufacturing.
The industrial audience will particularly value workshops geared toward their daily analytics challenges, as well as sessions focusing on IoT and AI applications in an industrial environment.
Case studies will provide an in depth look on how data science can help solve tangible problems encountered by corporations.
The scientific program will include invited plenary talks, as well as regular oral and poster sessions with contributed research papers, and data challenge sessions.

Organized by IEEE SPS,EPFL IC, EPFL STI, and the Swiss Data Science Center
26/06/2018 @ 14:00 room MXF 1

Evaluation of hearing devices in 3D audio environments: which 3D audio reproduction system(s)?

Laurent Simon, University Hospital Zurich

When designing new hearing devices (physical designs or algorithms), the quality of the new designs is evaluated almost exclusively through some sort of intelligibility experiment in limited conditions. This provides a better control but dismiss many of the problems that may occur in real life situations. As an alternative, it is possible to synthesize or reproduce realistic 3D audio environments using different loudspeaker- or headphone-based techniques. This talk will present measurements that were conducted in order to choose the most appropriated 3D audio reproduction system for hearing aids evaluation.

Bio:
Laurent Simon received his PhD in psychoacoustics from the University of Surrey in 2011. From 2011 to 2013, he studied audio source separation at INRIA, Rennes, before working on perceptual evaluation of binaural audio reproduction techniques at LIMSI until 2015. Laurent Simon is now doing a postdoc at the ORL Klinik of the University Hospital Zürich, where he studies the spatial auditory perception of patients using hearing aids, focusing on localization and distance perception.

Organized by Hervé Lissek
27/06/2018 @ 08:00 room STCC 2 52

Tech4Dev 2018: Voices of the Global South | Register Now!
Register for Tech4Dev 2018: Voices of the Global South! The UNESCO Chair in Technologies for Development, hosted by the Cooperation and Development Center-CODEV at the Swiss Federal Institute of Technology in Lausanne invites you to be part of its biennial World Class Event. Early Bird Registration ends of May 25th! Register Now! For more information please visit our website.

Background

The Tech4Dev Conference is the biennial flagship event of the UNESCO Chair in Technologies for Development hosted by the Cooperation & Development Centre (CODEV) at the Ecole Polytechnique Fédérale de Lausanne (EPFL).

The focus of the conference is the application of technology solutions to advance inclusive and economic development in the Global South.

Tech4Dev provides an opportunity to:
- Network across disciplines and fields of technology, to promote the development, deployment, adaptation, and scaling of new solutions for the Global South.
- Reinforce collaboration among diverse stakeholders - academics, engineers, entrepreneurs, policymakers, practitioners, and social scientists - for a holistic approach to addressing challenges in technology innovation and diffusion for development.
- Build capacity among students and young professionals to engage in multidisciplinary problem-solving for social impact.
Core Thematic Areas
- Technologies for Humanitarian Action
- Medical Technologies
- Science and Technology for Disaster Risk Reduction
- Technologies for Sustainable Access to Energy
- ICT for Development
- Technologies for Sustainable Habitat and Cities
Why You Should Attend the Tech4Dev Conferences?
- A unique multidisciplinary platform
- Showcase for cutting-edge research projects in Tech4Dev and case studies from the field
- Participation by 500 experts from over 75 countries
Organized by Cooperation and Development Center-EPFL
22/08/2018 @ 12:00 room RLC B1 520

Noon Talk #4: Publishing preprints

Marc Robinson, professeur au Département d'écologie et d'évolution à l'UNIL
Alain Foehn, doctorant au Laboratoire des constructions hydrauliques à l'EPFL

After a short introduction by Béatrice Marselli, EPFL Library, Marc Robinson, professor at the Department of evolution and ecology at UNIL, will present the benefits from publishing preprints. Alain Foehn, PhD student at the Laboratory of hydraulic constructions at EPFL, will share his experience with submitting a paper to Elsevier.

Introduction slides by Béatrice Marselli
Marc Robinson presentation
Alain Foehn presentation

Organized by EPFL Library
05/10/2018 @ 12:15 room GC B1 10

Engineering the China Zun

Dr Liu Peng, Director at Arup Beijing Office, Bejing, P.R. of China

The structural engineering of China Zun is a unique challenge in many aspects. Located in Beijing, the 528m office tower will be the tallest building in high seismic zones around the world. The enlarged top portion imposes difficulties never seen before in buildings of similar height. The shape and the functions of the building were adjusted many times and digitalized parametric design helped engineers to evaluate the structure performance and provide quantitative feedback in very short time. The high efficient structure is composed of a mega braced frame and a central concrete core. Composite members are widely used to obtain the best balance of seismic performance and cost, thanks to the experiences accumulated in the emerging tall building projects in China in recent 20 years. Although located in a very congested site the overall construction of the tower takes only five years and is expected to finish at the end of 2018.

Bio : Dr. Peng Liu is a director with Arup who leads Arup Beijing office. He has substantial experiences in tall building design, seismic design and China projects. He has been responsible for or involved in structural design of many projects in mainland China and Hong Kong, including Beijing CITIC Tower(“China Zun”) (528m), Beijing CBD Z6 Tower (408m), Beijing China World Tower 3A (330m) and 3B (288m), Beijing Fortune Plaza complex (max 260m), Tianjin Goldin 117 Tower (597m), Tianjin Kerry Center (333m), CCTV New Headquarters, Beijing National Stadium (“Bird’s nest”), Beijing Capital airport terminal 3, Hong Kong ICC (497m) etc. He is also the specialist in design automation and structural optimisation in Arup East Asian region, responsible for the relevant studies for a number of signature Arup projects and providing external value engineering services. He is a member of following professional associations : Institution of Structural Engineers, Hong Kong Institution of Engineers, City leader CTBUH.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Alexandre Alahi
12/10/2018 @ : room CE 1 5

Novel optical devices and methods for applications in quantum information processing, quantum communication and for fundamental quantum experiments

Prof. Dr. Christine Silberhorn, Univ. Paderborn, Paderborn, Germany, https://physik.uni-paderborn.de/silberhorn/

Organized by Dr. Raphaël Butté and Arnaud Magrez
12/10/2018 @ 12:15 room GC B1 10

CESS Seminar: Experimental assessment of the fabric and state parameters of active clays for modelling their hydro-chemo-mechanical behaviour

Prof. Mario Manassero (Politecnico di Torino) is the Vice-President for Europe of the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE) for the term 2017-2021. He obtained his Civil Engineering degree in 1980 at Politecnico di Torino and received his Ph.D. at the same university in 1987. He has been visiting professor at University of Ancona (Italy) from 1988 to 1993, Ghent University (Belgium) in 1996 and at Colorado State University (USA) in 1995. Since 1998, he has been professor of Geotechnical Engineering at Politecnico di Torino.

Abstract. The osmotic, hydraulic and self-healing efficiency of bentonite based barriers (e.g. geosynthetic clay liners) for containment of polluting solutes are governed both by the physico-chemical intrinsic parameters of the bentonite, i.e. the solid phase density (ρ_sk), the total specific surface (S), and the total fixed negative electric surface charge (s), and by the state and fabric parameters able to quantify the soil density and microstructure, i.e. the total (e) and nano (e_n) void ratio, the average number of platelets per tactoid (N_l,AV), the effective electric fixed-charge concentration (), and the Stern fraction (f_Stern). In turn, the fabric parameters seem to be controlled by the effective stress history, ionic valence and related exposure sequence of salt concentrations in the pore solution. A theoretical framework, able to describe the coupled chemical, hydraulic and mechanical behaviour of bentonites, has been set up. In particular, the relationships, which link the aforementioned intrinsic, state and fabric parameters of a given bentonite with its hydraulic conductivity (k), effective diffusion coefficient (), osmotic coefficient (w) and swelling pressure (u_sw) under different stress-histories and solute concentration sequences, are presented. The proposed theoretical framework has been validated through the comparison of its predictions with some of the available experimental results that have been obtained through the use of the last version of an ad hoc equipment able to detect, within a unique time step, all the aforementioned performance parameters, apart the hydraulic conductivity (k) that has been anyway measured by just a further time step carried out always with the same equipment and on the same bentonite sample.

Organized by Profs. Brice Lecampion & Alexandre Alahi
16/10/2018 @ 12:15 room MED 0 1418

MechE Colloquium: Systems analysis of wall turbulence: Characterizing self-sustaining processes

Prof. Beverley J. McKeon, McKeon Group, California Institute of Technology

Abstract:
The financial and environmental cost of turbulence is staggering: manage to quell turbulence in the thin boundary layers on the surface of a commercial airliner and you could almost halve the total aerodynamic drag, dramatically cutting fuel burn, emissions and cost of operation. Yet systems-level tools to model scale interactions or control turbulence remain relatively under-developed. The resolvent analysis for turbulent flow proposed by McKeon & Sharma (J. Fluid Mech, 2010) provides a simple, but rigorous, approach by which to deconstruct the full turbulence field into a linear combination of (interacting) modes. After a brief review of some key results that can be obtained by analysis of the linear resolvent operator concerning the statistical and structural make-up of wall turbulence, I will describe some of our recent progress towards determining how to reconstruct self-sustaining turbulent systems, both natural and synthetic. Implications for both the classical picture of wall turbulence and control of turbulent flows will be discussed.

Bio:
Beverley McKeon is Theodore von Karman Professor of Aeronautics at the Graduate Aerospace Laboratories at Caltech (GALCIT). Her research interests include interdisciplinary approaches to manipulation of boundary layer flows using morphing surfaces, fundamental investigations of wall turbulence at high Reynolds number, the development of resolvent analysis for modeling turbulent flows, and assimilation of experimental data for efficient low-order flow modeling. She was the recipient of a Vannevar Bush Faculty Fellowship from the DoD in 2017, the Presidential Early Career Award (PECASE) in 2009 and an NSF CAREER Award in 2008, and is an APS Fellow and AIAA Associate Fellow. She is the past editor-in-chief of Experimental Thermal and Fluid Science and currently serves as an associate editor of Physical Review Fluids, and on the editorial boards of the AIAA J., Annual Review of Fluid Mechanics and Experiments in Fluids. She is the APS representative and Vice Chair Elect of the US National Committee on Theoretical and Applied Mechanics.

Organized by MechE Colloquium
19/10/2018 @ 12:15 room GC B1 10

Development and Application of Hybrid Simulation for Seismic Testing of Large-scale Structural Systems

Professor Dr Gilberto Mosqueda, Professor of Structural Engineering, University of California, San Diego, USA

Hybrid simulation combining physical and numerical simulations provides a cost-effective means to experimentally examine the performance of large-scale structural systems under extreme loading events. It can be particularly beneficial to investigate the behavior of large scale structures subjected to seismic loads through collapse given that shake table tests pose significant risk to support a collapsing structure. To examine the reliability of the test method, hybrid simulation is first applied to a steel moment frame that has been the subject of previous collapse studies including shake table testing, extensive quasi-static component testing and numerical simulations. These past studies provide the benchmark data for verification and examining sources of errors in hybrid simulation. After developing reliable approaches to the test method, two series of hybrid simulations are presented that aim to trace the system-level seismic response of a four-story steel moment frame building structure through collapse. The experimental substructures include a half-scale 1½-bay by 1½-story physical substructure of a special steel moment-resisting frame and the physical substructure corresponding to the gravity framing system. The hybrid simulation test method is shown to be reliable and can provide insight into experimental behavior of structural subassemblies under realistic seismic loading given that errors are properly mitigated. Other large-scale applications of hybrid simulation will be discussed including testing of seismic isolation bearings in nuclear powerplants.

Bio : Gilberto Mosqueda is a professor in the Department Structural Engineering at the University at California San Diego since 2012. Previously, he was on the faculty at the University at Buffalo since 2004. He received his Ph.D. (2003) from the University of California at Berkeley, M.S (1998) from Massachusetts Institute of Technology, and B.S. (1996) from the University of California at Irvine all in civil engineering. He received the NSF CAREER award in 2008 and is currently on the editorial board for the journal Earthquake Spectra. The focus of his research is in the area of structural and earthquake engineering, particularly on understanding and improving the seismic performance of structural and nonstructural systems under seismic loads. Recent research has examined the seismic response of structural systems under extreme loads including the collapse of steel structures and limit states in seismic isolation system using hybrid simulation. He has over 100 publications in peer reviewed journals and conference proceedings and has led and participated in various reconnaissance mission following earthquakes around the world. Most recently he co-led the team organized by the Earthquake Engineering Research Institute to investigate damage from the 2017 Puebla-Morelos Earthquake in Mexico.

Organized by Prof. Dr Brice Lecampion & Prof. Dr Alexandre Alahi
26/10/2018 @ 12:15 room GC B1 10

Extensions of the hypercube queuing model to analyze emergency services systems inspired by practical applications

Dr. Ana Paula Iannoni, Ecole Centrale Paris

Emergency Service Systems (ESS), such as police, fire, and emergency medical services, have been modeled and studied since long ago. Hypercube queuing models have been proposed and applied to analyze such systems with users in queues and servers spatially distributed over a region. The work of our research group in this area has been oriented to extensions of the classic hypercube model allowing the relaxing of some of its limiting assumptions to be applied to real emergency services. Some of these extensions, that were inspired by practical applications, are: partial backup, multiple dispatching, distinct units and classes of calls, multiple priority classes in queue and cut-off policy. Recently, we have studied an approximation of hypercube model to study large merging ESS such as fire control and emergency medical services that work together with cross-trained personnel and share some of their units (called joint units). In this presentation, I propose to talk about this recent study that is a collaboration with Arthur Swersey and Cheng Hua from Yale University, New Haven.

Bio:
Ana Paula Iannoni has a diploma in production engineering at Federal University of Sao Carlos, Sao Paulo, Brazil. She received her B. S. and Ph. D. in production engineering from Federal University of Sao Carlos. Dr. Iannoni was a visiting Ph.D. student at Belk College of Business, University of North Carolina at Charlotte and held a post-doc at Production Engineering Department, Federal University of Sao Carlos. She is a former post-doc researcher at Laboratoire Genie Industriel, Ecole Centrale Paris, France. Her research interests lie in queuing theory, simulation and probabilistic location problems applied to emergency systems, and operations research applied to logistics and transportation systems.

Organized by Profs. Brice Lecampion & Alexandre Alahi
16/11/2018 @ 12:15 room GC B1 10

Engineering Timber-Concrete Composite Structures

Dr. Luca Sorelli is professor at Université Laval (Quebec) and director of the laboratory on Multiscale Characterization of Construction Materials (MCCM). He has worked at different international research groups, such as, the durability division at IFSTTAR (Paris), the civil engineering department at MIT (Cambridge) and the LCR research center of LafargeHolcim (Saint-Quentin-Fallavier). Dr. Sorelli is member of the industrial consortium CIRCERB on eco-responsible structure. The vision of his research group is to develop efficient material-to-structure approach for fostering structural applications of new composite materials, which can fulfil the needs of today society and address the environmental challenges.

Why not taking advantage of the potentials offered by both timber and concrete for engineering composite structures in terms of material saving, vibrational behavior and environmental imprint? Dr. Sorelli will present recent research advances in Timber-Concrete Composite (TCC), such as: (i) the extension of the dynamic theory of a composite beam to consider the effect of the rotatory inertia on the vibrational modes; (ii) an original multi-scale model for predicting the TCC structural behavior from the connector property; (iii) a novel composite connector made of UHPFRC and steel to guarantee the structural ductility; (iv) the multi-criteria design and laboratory validation of slender floor structures made of Glulam beam or CLT slab with a thin slab of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC). The result discussion will highlight the main features of TCC structures and a new outlook for future applications.

Organized by Prof. Brice Lecampion and Prof. Alexandre Alahi
23/11/2018 @ 12:15 room CM 1 221

Polymer composites in civil engineering applications

Prof. Gerald Pinter, Chair of Materials Science and Testing of Polymers, Department of Polymer Engineering and Science, Montanuniversitaet Leoben, Austria

Polymers are widely used in civil engineering applications, either as primary or as secondary structural components. Two examples are presented in this talk and appropriate design and life assessment methods are discussed.

Thermoplastic Pipes
Fracture mechanics lifetime and safety assessment of thermoplastics pipes is based on the knowledge of material specific creep crack growth (CCG). However, with common test methods the investigation of this failure mechanism is not possible in modern thermoplastic-pipe materials in a feasible time. For an accelerated generation of CCG an extrapolation concept based on fatigue tests with cracked round bar (CRB) specimens was developed and integrated into a lifetime prediction model for pressurized pipes. In that way it is possible to calculate the lifetime of pipe systems under real service conditions in a reasonable time.

Solar thermal façades
Utilizing façades for energy conversion, distribution, and storage is a key criterion for increasing the energy efficiency of buildings. In this regard, the usage of façade-integrated solar thermal collectors is highly interesting. However, high absorber temperatures during collector stagnation often cause a significant heat transfer from the collector to the interior and thus increase the interior thermal load. Whereas latent heat storage is already well established for active and passive cooling and thus for the heat management of buildings, recent numerical simulations also revealed their high potential to effectively prevent overheating of buildings with solar thermal façades. The proof of concept with appropriate polymeric latent heat storage (PCM-polymer compound) as well as a representative solar thermal façade element will be demonstrated.

Bio: Prof. Gerald Pinter is Chair of Materials Science and Testing of Polymers at the Department of Polymer Engineering and Science at the Montanuniversitaet Leoben, Austria and Area Manager of the Polymer Competence Center Leoben GmbH, the leading Austrian Center of Excellence for application oriented research in the field of polymeric materials. He is board member of the European Structural Integrity Society (ESIS-Austria), Carbon Composite Austria (CC Austria) and the European Society of Composite Materials (ESCM). The research of his group deals with the “Reliability of plastics and composites in structural applications” and “Sustainable materials and recycling technologies”.

Organized by Profs. Brice Lecampion & Alexandre Alahi
30/11/2018 @ 12:15 room GC B1 10

Utilization of physics-based simulated earthquake ground motions for performance assessment of tall buildings – validation, collapse safety, and machine learning tools for regional risk evaluation

Dr. Nenad Bijelić, postdoctoral scholar at the Unit of Applied Mechanics, University of Innsbruck, Austria

Limited data on strong earthquakes and their effects on structures poses one of the main challenges of making reliable risk assessments of tall buildings. For instance, while the collapse safety of tall buildings is likely controlled by large magnitude earthquakes with long durations and high low-frequency content, there are few available recorded ground motions to evaluate these issues. The influence of geologic basins on amplifying ground motion effects raises additional questions. Absent recorded motions from past large magnitude earthquakes, physics-based ground motion simulations provide an attractive alternative. This talk will focus on utilization of simulated ground motions for performance assessment of tall buildings with the following overall goals: (1) developing confidence in the use of simulated ground motions through comparative assessments of recorded and simulated motions; (2) identifying important characteristics of extreme ground motions for collapse safety of tall buildings; (3) exploring areas where simulated ground motions provide significant advantages over recorded motions for performance-based engineering. First, we will examine an effort to validate the use of physics-based simulations in engineering applications by using ground motions simulated with Southern California Earthquake Center’s (SCEC) Broadband Platform (BBP). Next, collapse risk of tall buildings in the Los Angeles basin will be investigated by contrasting conventional risk assessments with assessments obtained utilizing the SCEC CyberShake simulations. Finally, we will quantify the influence of basin effects on seismic collapse risk and present machine learning approaches for identification of efficient intensity measures and development of reliable collapse classification algorithms. Opportunities for future work will be discussed.

Bio:
Nenad Bijelić is currently a postdoctoral scholar at the Unit of Applied Mechanics, University of Innsbruck, Austria. He obtained his Ph.D. (2018) and M.S. (2014) from Stanford University, USA, and B.S. (2010) from University of Zagreb, Croatia all in civil engineering. In 2012 he received the Fulbright Science and Technology award to study earthquake engineering in the USA. His research is in the area of structural and earthquake engineering focusing on dynamics of nonlinear systems and application of statistical and machine learning tools. Focus of his recent research was on reliable risk assessment of tall buildings located in sedimentary basins through high-performance computing and utilization of emergent technologies in earthquake simulations. He is a reviewer for Natural Hazards Review and served as a reviewer for the 11^th U.S. National Conference on Earthquake Engineering.

Organized by Profs. Brice Lecampion & Alexandre Alahi
07/12/2018 @ 12:15 room CM 1 221

Relevance of Geotechnical Engineering for the Conservation of the Historic City of Venice

Prof. Paolo Simonini, Department ICEA, University of Padova, Italy

The worldwide-known historic city of Venice continues to preserve a rather precarious equilibrium with the surrounding lagoon, although the margin of security is being eroded at an ever increasing rate. The rate of environmental deterioration is being accelerated by the increasing frequency of the flooding of the historic city – referred as to ‘acqua alta’ (i.e. literally ‘high water’) - caused by the natural eustatic rise of the sea level, by natural subsidence and by a regional man-induced subsidence, the latter particularly important between 1946 and 1970.
From the late ‘60, several geotechnical studies on geotechnical were carried out and, to keep under control the evolution of subsidence, a continuous survey activity was at that time initiated and prosecuted up to nowadays.
But the continuous increase of the annual frequency of the city flooding causing additional environmental damages, induced the Italian Government to start with several projects, the MOSE project - involving the design and construction of movable gates located at the three lagoon inlets, the INSULAE project, namely the artificial elevation of islands, on which the historic buildings are founded, and other smaller projects, such, for instance, improvement of old building foundations, erosion mitigation intervention in the lagoon including the reinforcement of the existing jetties at the inlets, fish farm reopening ect.
Starting from the historic subsidence evolution, the seminar will provide a short overview of some relevant geotechnical issues that have been and have to be solved to realize the interventions to protect Venice and the surrounding lagoon from the increasing environmental deterioration.

SHORT CV

Paolo Simonini, MSc, PhD, Professor of Geotechnical Engineering at the University of Padova, Padova, Italy.

Studies:
1981, Graduation with honors in Civil Engineering (MSc), University of Padova (UNIPD);
1987: Doctoral Degree at the Technical University of Torino in Geotechnical Engineering.

Carrier history:
1987-89: Teaching assistant at the University of Trento;
1990-1998: Research assistant of Geotechnical Engineering at UNIPD;
1998-2004: Associate Professor at UNIPD;
2005: Professor of Geotechnical Engineering at UNIPD.
2009-2012: President of the Civil Engineering Council;
2012-2015: President of the School of Engineering, University of Padova.
2015-2018: President of the Italian Academic Society of Geotechnical Engineering
2016-2019: Co-Founder and Vice-President of the Civil and Industrial Safety Engineering Master Course.
2016-2018: President of the National Committee for Professorship Selection.

Focus on recent research:
Studies on geotechnical engineering for the preservation of historic city of Venice, namely the San Marco Square Project, to protect the most famous island of San Marco against recurrent flooding.

Site testing: Use of CPTU to predict maximum stiffness in soils; Applicability of SCPTU and SDMT to characterize the soils of the Venice Lagoon; CPTU calibration to predicting secondary compressions in sands and silts, MPM numerical modelling of CPTU penetration;

Site monitoring: Use of InSAR to monitor settlements on coastal structures; landslide monitoring and data interpretation, use of optical fibers to monitor subsurface groundwater flows;

Landslide: Evaluation of impact forces on structures realized to protect against rapid landslide and debris flow with MPM.

Studies on erosion processes and instability of leveee and dams in the Venetian Plain.

Some recent expert activities:
Member of the AGI Committee for standards in site investigation practice and of the AGI-AICAP Committee for standards in ground anchors.

Member of Scientific Council of International Research Society Interpraevent. The Research Society works to set up preventive protection against disasters and supports interdisciplinary research to protect our living space against flooding, debris flow, avalanches and mass movements.

Official member of the Material Point Method Community (Univ. Cambridge, UPC Barcelona, TU Delft, TU Hamburg-Harburg, Deltares; Virginia Tech, UC Berkeley).

Member of the Municipal Committee for the preservation of the Chapel of Scrovegni, the most relevant example of Giotto Painting in Italy.

Organized by Profs. Brice Lecampion & Alexandre Alahi
21/12/2018 @ 12:15 room GC B1 10

CESS Seminar: Three-dimensional X-ray tomography for multiscale characterization and fatigue damage investigations of composites for wind turbine blades

Lars P. Mikkelsen obtained his PhD in Solid Mechanics in 1995 at the Technical University of Denmark (DTU). After that, he has been a Carlsberg Clare Hall visiting follow at the Cambridge Center for Micromechanics as well as a visiting scholar at Harvard University. Has since 2001 worked at the current geographic location near Roskilde in Denmark, first as a senior scientist at the Material Research Department at the Risø National Laboratory and latest as an associate professor and head of section for the Composite Mechanics and Structure section at the DTU Wind Energy. Has more than 25 years’ of experience working with numerical modelling and experimental characterization of materials and structures. In the last 10 years, the work has focused on research in composite materials regarding compression strength and fatigue behavior of the load carrying laminates in wind turbine blades. During this, technique such as x-ray computer tomography and commercial finite element codes together with user defined user subroutines is used. Organizes onsite and e-learning courses on the master and PhD-level in those fields in addition to supervision of master and PhD students. Have throughout the years published more than 80 papers of which more than 40 is in international journals. Has two patent applications on strain gauges designs for composite testing.

Key mechanical properties of the load carrying composite laminates in wind turbine blades are the stiffness, fatigue resistance and the compression strength. While the overall design criteria for glass fiber composites mainly are stiffness driven, it tends to be more fatigue and compression strength driven when using carbon fiber or glass/carbon hybrids.
Using lab-source x-ray computer tomography in connection with ex-situ fatigue testing of quasi unidirectional composites, the local fiber failure can be followed. The material investigated is typical non-crimp fabric used in wind turbine blades. The fatigue damage evolutions is studied during tension/tension, tension/compression and compression/compression fatigue. It is found that the location of the tension/tension (R=0.1) and tension/compression (R=-1) fatigue damage are controlled by the bundle architecture, while the compression/compression (R=10) show up as small shear cracks located in the matrix between the fibers. In addition to fatigue damage investigations, the fiber architecture inside the fiber bundle and the fiber bundle architecture is studied. Based on a dictionary based segmentation method, the fiber-architecture inside the fiber bundle is explored.
Three-dimensional X-ray computer tomography large amount of data, typical between 2-50GB from each dataset. During publication, only a small amount of such data set can be shown. Therefore conclusions from such studies can be doubtful, if not the full data-set is made available together with the publication. Strategies for how to do this will be presented at the end of the talk.

Organized by Coordinators: Prof. Brice Lecampion and Prof. Alexandre Alahi
22/02/2019 @ 12:15 room GC B3 30

CESS Seminar: About the Origin of Cities

Prof. André de Palma, ENS Cachan - University Paris-Saclay

Abstract
We provide a barebones framework that uncovers the circumstances which lead either to the emergence of equally-spaced and equally-sized central places or to a hierarchy of central places. We show how these patterns reflect the preferences of agents and the efficiency of transportation and communication technologies. With one population of homogeneous individuals, the economy is characterized by a uniform distribution or by a periodic distribution of central
places having the same size. The interaction between two distinct populations may give rise to a hierarchy of central places with one or several primate cities.

Bio
André de Palma is a specialist in individual (and couple) decision making under risk and uncertainty, industrial organization and operations research. He has widely published in Economics and Transportation Journals. He is the father of Dynamic models in Transportation with Moshe Ben-Akiva, Richard Arnott and Robin Lindsay. He has also introduced Discrete choice models in industrial organization : His book, Anderson, de Palma and Thisse (1992), Discrete Choice Theory of Product Differentiation, MIT Press, is used worldwide in major institutions, and has become a classic.

Organized by Profs. Brice Lecampion and Alexandre Alahi
26/02/2019 @ 12:15 room MED 0 1418

MechE Colloquium: Tools and Processes for Printed Electronic Systems

Prof. Vivek Subramanian, Department of Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland and Department of Electrical Engineering and Computer Sciences, University of California, Berkeley

Abstract:
In recent years, there has been significant interest in the applications of printed electronics in the realization of a range of low-cost, large area, flexible electronic systems such as displays, distributed sensors, and low-cost disposable tags. To make printed electronics a viable technology, however, there is a need for significant innovations across all aspects of these systems, including realization of advanced printable materials, improvements in printing technology, and design and realization of devices and systems that exploit the capabilities of this emerging technology.
In this talk, I will review our progress in advancing the state of the art in printed electronics. I will begin by discussing the physical underpinnings of printing and will discuss how understanding and control of printing-related phenomena allows for substantial advancement in the capabilities of the same. I will additionally discuss advances in printable material systems that enable the realization of high-performance printed structures. In particular, I will discuss the importance of proper material design for use as printable precursors. Finally, I will show how the combination of advanced printed techniques with appropriate materials and proper device design may be used to realize printed devices with unprecedented performance levels, thus helping to usher in the era of printed electronics.

Bio:
Vivek Subramanian received his PhD in electrical engineering from Stanford University in 1998. Since 2000, he has been at the University of California, Berkeley, where he is currently a Professor of Electrical engineering and Computer Sciences. In 2018, Prof. Subramanian moved to École polytechnique fédérale de Lausanne, where he is a Professor of Microengineering.
Dr. Subramanian is a member of the Institute of Electrical and Electronic Engineers (IEEE). In 2002, he was nominated to Technology Review's list of top 100 young innovators (the TR100), and his work at Matrix Semiconductor was nominated to the Scientific American SA50 list for visionary technology. Awards he has received include the Paul Rappaport Award for the best paper in an IEEE EDS journal, the IEEE Device Research Conference and the IMAPS best paper awards, the 2015 IEEE Kiyo Tomiyasu Award, and the outstanding teaching award from the EECS Department at the University of California, Berkeley.

Organized by MechE Colloquium
01/03/2019 @ 12:15 room GC B3 30

CESS Seminar: Liquefaction of fully and nearly saturated granular soils, experimental investigations and theoretical approach

Prof. Waldemar Świdziński, Director of the Institute of Hydro-Engineering, Polish Academy of Sciences in Gdańsk, Geomechanical Department

Abstract
Liquefaction is one of the most spectacular phenomena of soil behaviour during which granular soil changes its properties from solid to liquid-like type. Due to its disastrous character, it has been a subject of investigations carried out by various researchers from many countries over many years. Although the basic factors governing the liquefaction phenomenon are quite well recognised, there are still some gaps requiring further studies and analyses. One of them is related to the degree of saturation of soils, which may be prone to liquefaction. For many years it was believed that one of compulsory conditions for soils to liquefy is full saturation. Recent investigations have shown that it may not be necessarily true. The second aspect, which requires further investigations, regards the content of fines fraction in the granular composition of the soil susceptible to the liquefaction process. Furthermore, the last but not least, a following question should be answered: may some types of rock undergo liquefaction as well? In the course of the presentation, some fundamental issues describing the liquefaction phenomenon, based on the results of experimental investigations carried out in various geotechnical laboratory devices (simple shear, standard, cyclic and true triaxial apparatuses) will be shown and discussed. Moreover, the proposed theoretical description of pore water generation during monotonic and cyclic loading for fully saturated as well as partially saturated granular soils will be presented.

Bio
Professor Waldemar Świdziński has been working at the Institute of Hydro-Engineering, Polish Academy of Sciences in Gdańsk, Geomechanical Department since 1981. At the Institute he obtained his PhD in Soil Mechanics in 1988. After that, he got a Postdoc position in the Geotechnical Laboratory at Delft Technical University, the Netherlands, where he spent over one year. Furthermore, he was awarded D.Sc. at the Technical University of Gdańsk in 2007 and became a Professor of the Institute in the same year. For many years he had been the head of the Geomechanical Department. Since 2016 he is a Director of the Institute. His main scientific interest is focused on mechanics of soil compaction and liquefaction, modeling the response of soil subjected to monotonic or cyclic loadings including earthquakes, stability analyses, dynamic analyses, experimental soil mechanics, as well as large scale modeling of groundwater flow and pollution transport. Prof. Świdziński obtained essential experimental, numerical and practical geotechnical engineering experience. Since 1984 to date, he is an expert for Tailings Storage Facility belonging to KGHM Polska Miedź S.A., one of the largest facilities of this type in the world, being an essential inspiration for many research problems. Throughout the years he has published more than 100 papers, 20 of which in well recognized, peer-review international journals.

Organized by Profs. Brice Lecampion and Alexandre Alahi
08/03/2019 @ 12:15 room GC B3 30

CESS Seminar: STIMTEC – stimulation experiments and their validation in the Reiche Zeche underground laboratory, Freiberg, Germany

Professor Jörg Renner, Professor for Experimental Geophysics at Ruhr-Universität Bochum

The presentation will cover the ongoing research of the STIMTEC underground experiment designed to investigate the permeability enhancement associated with hydrofracturing and activation of shearing as for example targeted in deep geothermal projects. We combine periodic pumping tests, high resolution seismic monitoring, structural analysis and drilling into stimulated volumes in an effort to improve near-real-time monitoring, phenomenological models of stimulation processes, and prognosis strategies. The ongoing experiment is located at the Reiche Zeche underground laboratory below Freiberg in Saxony/Germany at a depth of about 130 m below surface in metamorphic gneisses. A structural analysis of the test volume enclosed by tunnels preceded the experimental program. The installed seismic network consists of 12 broad-band acoustic emission sensors (sensitivity 1-100 kHz) and three 1-component Wilcoxon accelerometers (sensitivity 50 Hz-25 kHz). The stimulation borehole with 63 m length was drilled with 15° northward inclination. Previous investigations suggest a strike-slip regime with the maximum horizontal stress striking N350. Field testing was accompanied by a series of laboratory tests on core samples to estimate fracture toughness and elastic properties of the gneiss. After an extended campaign characterizing the hydraulics of the test volume, ten stimulation tests were performed in the injection borehole during which a total of > 10000 high frequency events were recorded. Each stimulation stage consisted of a frac stage, several refracs, and a subsequent hydraulic testing period. On the basis of the ongoing analyses of test records we are currently deciding on the location of three validation boreholes to be drilled in spring 2019.

Bio
After his dissertation at the Ruhr-Universität Bochum (RUB), Jörg Renner held postdoctoral fellowships and appointments at Massachusetts Institute of Technology with intermittent stints at GFZ Potsdam as guest scientist and at a borehole-service company as senior engineer before he became Professor for Experimental Geophysics at Ruhr-Universität Bochum end of 2001. His major research interests are in two strongly linked topics, subsurface fluid transport and rheology of rocks. He addresses problems from groundwater flow near the surface to resource recovery from the upper crust to melt transport in the Earth's mantle by performing and analyzing field and laboratory experiments.

Organized by Coordinators: Prof. Brice Lecampion and Prof. Alexandre Alahi
11/03/2019 @ 17:15 room SV 1717

Paywall: The Business of Scholarship - Film Screening

Luc Henry, Scientific Advisor, EPFL Presidency, Tobias Philipp, OA Coordinator at SNSF, Béatrice Marselli, Publication Services Coordinator at EPFL Library, Céline Saudou, Coordinator of electronic collection at EPFL Library

The EPFL Open Science Initiative and the EPFL Library present
Paywall: The Business of Scholarship

Everyone on campus is invited to join the conversation about Open Access. To provide an entertaining – however interesting – introduction to the topic, we will screen the documentary movie (duration: 65 minutes), followed by an apéro.

Free movie! Followed by open conversation at the bar. Click on this link for registration (required).

Paywall: The Business of Scholarship is a documentary/advocacy film that dissects the current state of affairs of scholarly publishing. While the director cannot hide its convictions – and never attempts to – it is through the mouth of a number of esteemed experts and long-term Open Access advocates that he exposes the flaws of the current academic publishing system, and provides a glimpse into what the future could look like.

Director Jason Schmitt is a professor at Clarkson University in Potsdam, NY as well as a filmmaker and journalist.Film reviews were published in Nature, Science, New Scientist, Inside Higher Education, and many more. Since the film premiere in September 2018, it was screened in over 350 locations altogether, including in Hawaii, Greenland, Azerbaijan and … Switzerland.

Organized by EPFL Open Science Initiative and Library
15/03/2019 @ 12:15 room GC B3 30

CESS Seminar: Multiscale methods for predicting the long‐term creep deflection of concrete structures

Prof. Luca Sorelli, professor at Université Laval (Quebec), director of the laboratory on Multiscale Characterization of Construction Materials (MCCM)

Abstract
Recent works have shown that the several national codes provide alarming unsatisfactory prediction of the long-term deflection of concrete bridges being monitors in USA. The crux of the problem is to predict long-term (e.g., 30-50 years) deflection from laboratory short-term tests (e.g., over few years, if not months). Can we predict the long-term deflection of concrete structures by laboratory short-term tests?
To answer, this work takes a different approach to characterize concrete creep by explicitly considering the creep mechanisms that are at stake at the microstructure scale. Thanks to the tiny-probed volume, nano- and micro-indentation can quickly access to the long-term creep properties. This talk presents latest results on the effect of water, which allows speculating that the rapid equilibrium between capillary and disjoining forces affects the creep mechanism between the C-S-H sheets at the smaller scale. After modeling the dual creep/relaxation mechanism of creep by viscoelastic theory, the creep compliance function are up-scaled by micromechanics to predict the long-term creep. Finally, the up-scaled creep curve for mortar and concrete is compared against experimental results, the logarithmic basic creep formula of 2010 fib model code and the well-recognized Bazant B4 model.

Bio
Dr. Luca Sorelli is professor at Université Laval (Quebec) and director of the laboratory on Multiscale Characterization of Construction Materials (MCCM). He has worked at different international research groups, such as, the durability division at IFSTTAR (Paris), the civil engineering department at MIT (Cambridge) and the LCR research center of LafargeHolcim (Saint-Quentin-Fallavier). Dr. Sorelli is member of the industrial consortium CIRCERB on eco-responsible structure. The vision of his research group is to develop efficient material-to-structure approach for fostering structural applications of new composite materials, which can fulfil the needs of today society and address the environmental challenges.

Organized by Profs. Brice Lecampion & Alexandre Alahi
22/03/2019 @ 12:15 room GC B3 30

CESS Seminar: Fundamentals of brittle failure at the atomic scale

Dr. Laurent Brochard, researcher in Civil Engineering at Laboratoire Navier (ENPC, CNRS, IFSTTAR)

Abstract
Brittle failure is ubiquitous in civil engineering materials from concrete to rocks and faults. And yet, how brittle failure initiates is still debated. While the failure of pre-cracked bodies is predicted by an energy criterion (fracture mechanics), that of flawless materials is usually given by a stress criterion, and no clear scientific consensus exists about intermediate cases (e.g., notch). In this work, we use atomistic simulation techniques to investigate the elementary mechanisms behind brittle failure. A difficulty, though, is that the process zone size of the studied material must be nanometric to comply with the computational limits of molecular simulations. Very few materials exhibit such a small process zone (e.g., the process zone of rocks is typically 10-100 mm) and the candidate material we study is graphene. We also investigate a fictitious material (2D triangular lattice with harmonic interactions between closest neighbours).
Investigating the failure behaviour of graphene in various configurations, we characterize the transition from the energy criterion of fracture mechanics to the stress criterion. Interestingly, one particular situation exhibits an unexpected result: when the distance between two crack tips approaches the process zone size, the average stress in-between the tips exceeds the strength. While most macroscopic theories of initiation would not expect this behaviour, Leguillon’s criterion does [1]. Leguillon’s criterion is a finite fracture mechanics approach requiring both energy and stress criteria to be fulfilled over an initiation length. The peculiarity of our situation is that energy is the limiting factor since stress is highly concentrated between the tip while only little mechanical energy is available in the material [2].
To further investigate the atomic processes of failure, we consider the athermal limit (0K). Since atomic interactions are conservatives, failure can be viewed as an instability arising when one of the eigenvalues of the hessian matrix becomes negative. And the associated eigenvectors provides a description of the elementary mechanism of failure. Interestingly, failure of flawless materials exhibits infinite failure bands the width of which recalls the process zone size, i.e., a property that one usually gets from a cracked material. The corresponding eigenvalue are highly degenerated, whereas for flawed materials, the eigenvalues have little or no degeneracy and failure involves localized atom moves only.
At non-zero temperature, failure is no more deterministic because of thermal agitation. We conduct an extensive study over many time and length scales and identify a temperature-time-size equivalence that can be formalized by a universal scaling law of strength and toughness which extends Zhurkov’s theory [3] to size effects [4]. Interestingly, the scaling of strength and toughness differ only regarding the scaling in size, and therefore was not previously identified in Zhurkov’s work. One can formally relate this difference to the degeneracy of the negative eigenvalues in the athermal limit. Such scaling law is also of very practical interest to relate failure properties at different length and time scales.

[1] Leguillon, D. (2002). Strength or toughness? A criterion for crack onset at a notch. European Journal of Mechanics, A/Solids, 21(1), 61–72.
[2] Brochard, L., Tejada, I. G., & Sab, K. (2016). From yield to fracture, failure initiation captured by molecular simulation. Journal of the Mechanics and Physics of Solids, 95, 632–646.
[3] Zhurkov, S. N. (1984). Kinetic concept of the strength of solids. International Journal of Fracture, 26(4), 295–307.
[4] Brochard, L., Souguir, S., & Sab, K. (2018). Scaling of brittle failure: strength versus toughness. International Journal of Fracture, 210(1-2), 153–166.

Bio
Laurent Brochard is a researcher in Civil Engineering at Laboratoire Navier (ENPC, CNRS, IFSTTAR) since 2012. He received his M.S. and Ph.D. from Ecole des Ponts ParisTech in 2008 and 2011. He is also engineer from Ecole Polytechnique (France) and from École des Ponts ParisTech (France). His research focuses on multi scale approaches for the study of the physics and mechanics of materials with emphasis on phenomena that have their origin at the molecular scale: adsorption and poromechanics, fracture mechanics and failure initiation, thermo-mechanical couplings. Targeted applications are mostly in geomechanics (CO2 sequestration, nuclear waste storage, unconventional oil and gas, cementitious materials).

Organized by Profs. Brice Lecampion & Alexandre Alahi
27/03/2019 @ 12:15 room BC 420

Open Access across scales – from data to software, hardware and ideas

Pavel Tomancak
The EPFL Open Science initiative invites you to this presentation by Pavel Tomancak, senior group leader at the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Dresden, Germany.

ABSTRACT
Science is a collective endeavor and no matter what, we always stand on the shoulders of giants. Therefore, by definition, sharing everything scientific openly across the scientific community is paramount to progress. This obvious truth has been de-emphasized in the last decades of the 20th century as the scientific competition intensified. The Open Access (OA) movement emerged to partially remedy the situation. Pavel Tomancak will discuss his personal experiences with pushing OA agenda in various areas of scientific process including data, software, hardware, publications and institute operational models. Successes as well as failures will be highlighted, hopefully providing some inspiration for those who would like to try this at home.

The emphasis on open access in Pavel's career resulted in establishment of major resources such as Fiji and OpenSPIM.

Fiji (aka "Fiji Is Just ImageJ") is an open source image processing package based on ImageJ. Its main purpose is to provide a distribution of ImageJ with many bundled plugins. It was first presented to the ImageJ community in 2008. The original paper describing the core software project was published in 2012 and has now gathered over 12,000 citations.

OpenSPIM is an Open Access platform for applying and enhancing Selective Plane Illumination Microscopy (SPIM). As stated on their website, the researchers behind the initiative "hope that OpenSPIM in its radical openness will demonstrate that the benefits brought to science by the Open Source approach apply equally well to hardware." In particular, it is designed to be as accessible as possible:
- detailed, easy-to-follow build instructions
- off-the-shelf components and 3D-printed parts
- Modular and extensible design
- completely open blueprints
- completely Open Source
BIO
Pavel Tomancak studied Molecular Biology and Genetics at the Masaryk University in Brno, Czech Republic. He then did his PhD at the European Molecular Biology Laboratory in the field of Drosophila developmental genetics. During his post-doctoral time at the University of California in Berkeley at the laboratory of Gerald M. Rubin, he established image-based genome scale resources for patterns of gene expression in Drosophila embryos. Since 2005 he leads an independent research group at the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) in Dresden where he became senior research group leader in 2013. His laboratory continues to study patterns of gene expression during development by combining molecular, imaging and image analysis techniques. The group has lead a significant technological development aiming towards more complete quantitative description of gene expression patterns using light sheet microscopy. The Tomancak lab is expanding the systematic analysis of gene expression patterns to other Drosophila tissues and employing the comparative approach in other Drosophilids and invertebrate species.
Organized by Luc Henry
29/03/2019 @ 12:15 room GC B3 30

CESS Seminar: Routing Games in Traffic Networks with Mixed Autonomy

Prof. Ramtin Pedarsani, University of California Santa Barbara

Abstract
In this talk, we propose a macroscopic model for studying routing on networks shared between human-driven and autonomous vehicles that captures the effects of autonomous vehicles forming platoons. We use this to study inefficiency due to selfish routing and bound the Price of Anarchy (PoA), the maximum ratio between total delay experienced by selfish users and the minimum possible total delay. We find these bounds depend on: 1) the degree of the polynomial in the road cost function and 2) the degree of asymmetry, the difference in how human-driven and autonomous traffic affect congestion. We demonstrate that these bounds recover the classical bounds when no asymmetry exists.

In the second part of the talk, we develop a model of road congestion on shared roads based on the fundamental diagram of traffic. We further design optimal routing algorithms when users have varying degrees of altruism. We find that even with arbitrarily small altruism, total latency can be unboundedly better than without altruism, and that the best selfish equilibrium can be unboundedly better than the worst selfish equilibrium. We validate our theoretical results through microscopic traffic simulations and show average latency decrease of a factor of 4 from worst-case selfish equilibrium to the optimal equilibrium when autonomous vehicles are altruistic.

Bio
Ramtin Pedarsani is an assistant professor in the ECE department at UCSB. He obtained his Ph.D. in Electrical Engineering and Computer Sciences from UC Berkeley in 2015. He received his M.Sc. degree at EPFL in 2011 and his B.Sc. degree at the University of Tehran in 2009. His research interests include machine learning, game theory, information and coding theory, and transportation systems. He is the recipient of the best paper award in the IEEE International Conference on Communications (ICC) in 2014.

Organized by Profs. Brice Lecampion & Alexandre Alahi
05/04/2019 @ 12:15 room GC B3 30

CESS Seminar: Utilization of physics-based simulated earthquake ground motions for performance assessment of tall buildings – validation, collapse safety, and machine learning tools for regional risk evaluation

Dr. Nenad Bijelić, postdoctoral scholar at the Unit of Applied Mechanics, University of Innsbruck, Austria

Limited data on strong earthquakes and their effects on structures poses one of the main challenges of making reliable risk assessments of tall buildings. For instance, while the collapse safety of tall buildings is likely controlled by large magnitude earthquakes with long durations and high low-frequency content, there are few available recorded ground motions to evaluate these issues. The influence of geologic basins on amplifying ground motion effects raises additional questions. Absent recorded motions from past large magnitude earthquakes, physics-based ground motion simulations provide an attractive alternative. This talk will focus on utilization of simulated ground motions for performance assessment of tall buildings with the following overall goals: (1) developing confidence in the use of simulated ground motions through comparative assessments of recorded and simulated motions; (2) identifying important characteristics of extreme ground motions for collapse safety of tall buildings; (3) exploring areas where simulated ground motions provide significant advantages over recorded motions for performance-based engineering. First, we will examine an effort to validate the use of physics-based simulations in engineering applications by using ground motions simulated with Southern California Earthquake Center’s (SCEC) Broadband Platform (BBP). Next, collapse risk of tall buildings in the Los Angeles basin will be investigated by contrasting conventional risk assessments with assessments obtained utilizing the SCEC CyberShake simulations. Finally, we will quantify the influence of basin effects on seismic collapse risk and present machine learning approaches for identification of efficient intensity measures and development of reliable collapse classification algorithms. Opportunities for future work will be discussed.

Bio
Nenad Bijelić is currently a postdoctoral scholar at the Unit of Applied Mechanics, University of Innsbruck, Austria. He obtained his Ph.D. (2018) and M.S. (2014) from Stanford University, USA, and B.S. (2010) from University of Zagreb, Croatia all in civil engineering. In 2012 he received the Fulbright Science and Technology award to study earthquake engineering in the USA. His research is in the area of structural and earthquake engineering focusing on dynamics of nonlinear systems and application of statistical and machine learning tools. Focus of his recent research was on reliable risk assessment of tall buildings located in sedimentary basins through high-performance computing and utilization of emergent technologies in earthquake simulations. He is a reviewer for Natural Hazards Review and served as a reviewer for the 11^th U.S. National Conference on Earthquake Engineering.

Organized by Profs. Brice Lecampion and Alexandre Alahi
30/04/2019 @ 15:00 room BC 420

Opportunities for Automating Email Processing

Soya Park

Most people can relate to email overload. The good news is that some of the hassle of dealing with email could be automated away.  We performed a mixed-methods, need-finding study to learn what kind of automated email handling users want, and what kinds of information and computation are needed to make those automations reality. Our results highlight the need for a richer data model for prioritizing messages and more ways for managing attention and leveraging the status of a user’s inbox and schedule. Half of the automation methods we considered are impossible in popular email clients, which means new design directions should be explored.

Soya Park is a PhD candidate in MIT CSAIL advised by David Karger. Her research focuses on helping people manage and automate their information repositories. Her research interests lie at the intersection of end-user programming, information retrieval, and human-computer interaction. Her PhD is supported by a Kwanjeong Fellowship. She won a Cadence’s Women in Technology scholarship.

Organized by DLAB
03/05/2019 @ 12:15 room GC B3 30

CESS Seminar: An MINLP and a continuous-optimization approaches for aircraft conflict avoidance via speed and heading angle deviations

Prof. Marcel Mongeau, Professor in Operations Research at ENAC (École Nationale de l'Aviation Civile) in Toulouse, France

Abstract:
We propose two approaches to address a challenging problem arising in Air Traffic Management, that of keeping at all times a distance between any pair of aircraft throughout their flight trajectory above a threshold value. We address the problem by adjusting both aircraft speeds and heading angles simultaneously. Both the mixed-integer nonlinear programming model and the penalty continuous optimization model we are introducing deal with the complex aircraft separation constraints through reformulations. Numerical results validate the proposed approaches.

Bio:
Marcel Mongeau received his BSc (1985) and MSc (1987) degrees in Mathematics from Universite de Montreal, and his PhD (1991) in Combinatorics & Optimization from the University of Waterloo (Canada). He was then a post-doctoral researcher at CRM (Universite de Montreal), at INRIA (France) and at the University of Edinburgh. From 1994 to 2011, he was at IMT, Universite Paul Sabatier (France), where he received a Habilitation à Diriger des Recherches in 2003. He is currently Professor in Operations Research at ENAC in Toulouse (France). His research interests include Global Optimization, Numerical Optimization, and Operations Research with applications to aeronautics.

Organized by Profs. Brice Lecampion & Alexandre Alahi
07/05/2019 @ 12:15 room GR C0 01

EESS talk on "Decision making: a serious game!"

Dr Alice Aubert, SNSF Ambizione fellow in the Cluster of Decision Analysis, Dept Environmental Social Sciences, EAWAG

received in 2018 a 4-year SNSF Ambizione grant for an interdisciplinary project on citizen involvement in complex decision-making, in particular for wastewater infrastructure. The focus is on gamification and behavioural operational research. Initially trained as an environmental scientist, she carries out the research at Eawag – the Swiss Federal Institute of Aquatic Science and Technology.

Abstract:
Recently, many call for public participation to support environmental decision-making. Methods enabling structured and transparent decision-making when facing complex problems need to evolve. Environmental Multi-Criteria Decision Analysis (MCDA) is such a decision-making method. Urban wastewater management (UWM) is a good example of a complex decision that would benefit from citizens’ participation. The reason is that UWM relies on public investments, and alternative UWM options can induce changes in the daily life of end-users. Knowing the preferences of stakeholders and ideally of many end-users would facilitate decision-making.
So far, applications of environmental MCDA mostly fit the deliberative democracy framework, where selected stakeholders are included in decision-making. However, one could use environmental MCDA in a participatory democracy framework, involving many citizens, as well. However, this raises the following question: How to elicit reliable preferences from many citizens?
Gamification and serious games are nowadays pervasive. Increasingly more people use them to communicate about the complexity of the real world with simplified models. Gamification and serious games trigger psychological factors, which in turn have behavioural impacts, such as enhancing participation, and learning. However, scientifically rigorous evaluations of their actual benefits and possible drawbacks are scarce.
During the talk, I will discuss the gamification of environmental MCDA for online preference elicitation, based on experimental results. The first prototype tested with students produced encouraging results. The online-gamified preference elicitation tool helped participants to learn about UWM, and to construct preferences. The prototype requires improvements, and complementary experimental testing.

Organized by EESS - IIE
10/05/2019 @ 12:15 room GC B3 30

CESS Seminar: Earthquake vulnerability assessment of soil - foundation - structure systems

Prof. Dimitris Pitilakis, Associate Professor, Department of Civil Engineering, Aristotle University of Thessaloniki, Greece

Abstract
Earthquake vulnerability is a major contributor to seismic risk, while vulnerability assessment is an essential tool for the identification and mitigation of earthquake losses. Over the last years, significant research work has been made towards the development of a comprehensive methodology regarding the estimation of the expected earthquake losses and the resilience of man-made structures, while researchers have developed analytical, empirical, judgment-based and hybrid fragility curves covering a wide variety of structural typologies. To date, fragility curves are derived assuming fixed-base conditions, ignoring soil-structure interaction (SSI) and local site effects, yet these effects may play either a beneficial or a detrimental role to the seismic response of the structures. In this context, the influence of (i) SSI and (ii) nonlinear soil behavior on earthquake vulnerability assessment of structures needs further investigation. This lecture is built upon this scientific shortage, discussing efficient approaches to tackle the ever-emerging problem of the earthquake vulnerability assessment of civil engineering soil - foundation - structure systems.

Bio
Dimitris Pitilakis is Associate Professor in the Department of Civil Engineering of the Aristotle University of Thessaloniki, Greece (M.Sc. University of California, Berkeley, Ph.D. in earthquake engineering from Ecole Centrale Paris, France). He is an expert in geotechnical earthquake engineering, with emphasis on soil – foundation – structure interaction, dynamics of foundations and performance-based design. Lately, he has been working on the earthquake vulnerability assessment of soil-foundation-structure systems, in local and in city scale. He is a member of national and international scientific societies on Earthquake Engineering and reviewer of international scientific journals. He has developed software for the simulation of the soil- foundation- structure interaction, with emphasis on nonlinear soil behavior, as well as software for foundation design and analysis. He has significant experience in experimental soil-foundation-structure interaction in small-scale (shaking table and centrifuge) and full-scale (EuroProteas in Euroseistest http://euroseisdb.civil.auth.gr/sfsis) facilities. He is currently in charge of the shaking table facility of the Aristotle University of Thessaloniki, and of the full-scale EuroProteas facility.

Organized by Profs. Brice Lecampion & Alexandre Alahi
31/05/2019 @ 12:15 room GC B3 30

CESS Seminar: Probabilistic Analysis of Bonded Joints in Metallic Structures

Prof. Mina Dawood, Associate Professor, Department of Civil and Environmental Engineering, University of Houston

Abstract:
Bonded repairs of metallic structures, particularly using composite materials, have gained wide research attention in the past decade. However, the debonding strength of bonded joints exhibits a relatively high uncertainty compared to other strength-based limit states in structural applications. This uncertainty is compounded by various factors including the difference between the tensile and shear responses of typical polymeric adhesives, the effect of surface preparation on failure modes and capacities, and the interaction between interface strength and interface toughness. This presentation summarizes the ongoing experimental and analytical research efforts at the University of Houston to help quantify the uncertainty in the strength of bonded joints in metallic structures with an emphasis on the bond between steel and carbon fiber reinforced polymers.

Bio:
Mina Dawood is an Associate Professor in the Department of Civil and Environmental Engineering at the University of Houston where he has been a full-time faculty member since 2009. His research interests lie broadly in the field of implementation of new materials in civil infrastructure applications for both new construction and repair and rehabilitation of existing structures. Dr. Dawood is an Associate Editor of the ASCE Journal of Composites for Construction and a member of the Council of the International Institute of FRP in Construction (IIFC). He has co-authored nearly 50 archival journal publications and a comparable number of conference papers. He has been a PI or Co-PI on research projects funded by the National Science Foundation, US Department of Education, National Cooperative Highway Research Program, Qatar National Research Fund, Texas Department of Transportation, and private industry.

Organized by Profs Brice Lecampion & Alexandre Alahi
02/09/2019 @ 08:30 room EPFL BC (room tbc)

Summer School 'Open Science in Practice' 2019

Various

Eurotech Summer School, EPFL, Lausanne, Switzerland - 2-6 September 2019

"Open" is the new black. Everybody talks about open science. But what does it mean exactly?

Open Access, Open Data, Open Source, reproducible science. Jargon or concrete action?

This summer school is for anyone interested in learning how to improve the quality and impact of research. The course will take place over five days, with a large part of the program dedicated to workshops and tutorials to learn useful tips and tricks that will make your life easier. Instructors will present their experience and expertise on how you can adopt open science tools and best practice to your research more efficient, reproducible, visible and impactful.

We bring together established scientists and early career researchers to provide a stimulating, yet friendly, learning environment. No preliminary knowledge of open science is required!

Registration deadline is Friday 19 July 2019, 17:00 CET

2 ECTS for doctoral students

More information on the course website.

Confirmed speakers include:

Rachael Ainsworth - Radio Astronomer, University of Manchester, UK
Adrien Ball - Senior Machine Learning Engineer, SNIPS, Paris, France
Anita Bröllochs - Head of Outreach, Protocols.io, USA
Fatma Deniz - Postdoctoral Fellow, University of California Berkeley, and Visiting Scientist, Technical University Berlin, Germany
Tim Head - Software Developer, Wild Tree Tech and Skribble
Stephan Heunis - PhD candidate at the Electrical Engineering department of the Eindhoven University of Technology, The Netherlands
Michel Jaccard - Lawyer, Associate at id est avocats, Lausanne, Switzerland
Wenzel Jakob - Professor at the School of Computer and Communication Sciences, EPFL, Switzerland
Galina Limorenko - PhD candidate in the School of Life Sciences, EPFL, Switzerland
Charlotte Mazel-Cabasse - Executive Director of the Digital Humanities Center, UNIL-EPFL, Switzerland
Marc Robinson-Rechavi - Professor of Bioinformatics, UNIL, and Group Leader, Swiss Institute of Bioinformatics, Lausanne, Switzerland
Melanie Röthlisberger - Senior Research and Teaching Associate, English Department, University of Zurich, Switzerland
Sina Rüeger - Postdoctoral Researcher, EPFL, Switzerland
Frédéric Schütz - Statistician, Swiss Institute of Bioinformatics, Lausanne, Switzerland
Malvika Sharan - Computational Biologist, EMBL, Heidelberg, Germany
Bruno Strasser - Professor of History of Science, University of Geneva, Switzerland
Maximilian Strauss - Postdoctoral Researcher, Ludwig-Maximilians Universität München and Max Planck Institute of Biochemistry, Germany
Jon Tennant - Rogue Palaeontologist, Interdisciplinary Research Center (CRI), Paris, France
Charlotte Teresa Weber - Researcher at The Arctic University of Norway in Tromsø, Norway
Martin Vetterli - Professor of Engineering and President at EPFL, Lausanne, Switzerland

Organized by Luc Henry, Scientific Advisor, EPFL Presidency
20/09/2019 @ 14:00 room GC A3 30

Constitutive Modeling of Strain Rate Sensitive Polymeric Gels and Biological Tissues

Prof. Ghatu Subhash, Newton C. Ebaugh Professor, Mechanical and Aerospace Engineering, University of Florida

Abstract:
A comprehensive experimental and analytical modeling effort is carried out to capture the visco-hyperelastic response of soft materials. The commonly used thermodynamic dissipation-based models utilize strain energy density and dynamic viscous dissipation potentials, and have been studied to describe short-time memory responses of soft materials for over two decades. In this study, it is demonstrated that the existing forms of viscous dissipation potential in the literature do not capture strain rate dependence of elastic moduli and Poisson’s ratio, a phenomenon which has been experimentally observed in many soft tissues and polymeric gels. To capture the overall response of these materials, the current work is carried out in two phases: First, a generalized thermodynamic stability criterion for isotropic finite elastic solids is derived using the fundamental balance laws and field equations of continuum mechanics, which is then used to formulate constitutive inequalities for the polynomial forms of hyperelastic constitutive equations. It is shown that the model constants of a hyperelastic constitutive model should fall within a domain called the Region of Stability (ROS) for all three primary deformation modes, i.e., uniaxial compression, uniaxial tension and shear. It is then shown that experimental data from only a particular deformation mode of deformation may not capture the complex behavior of a material under multiaxial state of stress for hyperelastic materials and hence data must be captured from all three deformation modes to obtain a realistic constitutive behavior. Second, a novel generalized viscous dissipation potential form is proposed, which not only captures strain rate sensitivity, but also consists of physically-based model parameters that relate to the material’s strain rate sensitivity behavior. The proposed viscous dissipation potential is combined with standard polynomial-based hyperelastic strain energy density function to define visco-hyperelastic constitutive equation, which is then used to model quasi-static to high strain rate response of soft materials such as hydrogel, ballistic gelatin, human patellar tendon, porcine brain tissue. Finally, challenges of conducting simple shear experiments on hyperelatic materials are highlighted. The robustness of constitutive model for capturing deformations under complex loads such as wedge-indentation and high velocity long-rod impact on a rigid surface are demonstrated.

Bio:
Professor Subhash obtained his PhD from University of California San Diego (UCSD) in 1991 and conducted post-doctoral research at California Institute of Technology (Caltech) during 1992-93. He joined Michigan Technological University in 1993 and then moved to University of Florida in 2007.
His research expertise is in multiaxial dynamic constitutive behavior of materials, processing-microstructure-property-performance relationships in advanced structural ceramics, and experimental solid mechanics. His research efforts have focused on understanding the deformation mechanisms in a range of materials including refractory metals, bearing steels, bulk metallic glasses, ultrahard ceramics, low-density foams, nuclear ceramics, brain tissue, and polymeric gels. In the context of ceramics, his research is focused on experimental and computational investigations on pressure-induced amorphization in icosahedral ceramics. In the field of nuclear engineering, he has developed rapid processing technology to fabricate nuclear fuel and control rod pellets in few minutes compared to the traditional methods which take several hours. For this effort, he has received ‘Significant Contribution Award’ from Materials Science and Technology Division, American Nuclear Society (2014). His contributions in experimental solid mechanics have been recognized by the 2018 ‘Frocht Award’ from Society for Experimental Mechanics(SEM). His current research interests in biomedical engineering include determination of contractile stresses due to cell growth in tissue phantoms and shock-induced cellular degradation in brain tissue. His work on rolling contact fatigue of ultrahard bearings received ‘Best Paper Award’ in the Journal of Engineering Materials and Technology (2017).
Prof. Subhash is a fellow of the ASME and SEM. He serves as an Editor-in-Chief of Mechanics of Materials (an international journal) and as an Associate Editor of the Journal of the American Ceramic Society. He has received numerous recognitions for excellence in teaching, research and professional service, including ‘Technology Innovator Award’ from University of Florida (2016) and Teacher/Scholar of the year (2013), ASME Student Section Advisor Award, Society of Automotive Engineers (SAE) Ralph R. Teetor Educational Award, and American Society for Engineering Education (ASEE) Outstanding New Mechanics Educator. He has graduated 34 PhD students and co-authored 190 peer reviewed journal articles, 80 conference proceedings, and 5 patents. He has co-authored a book on “Mechanics of Materials Laboratory Course” and is finalizing another book on “Dynamic Response of Ceramics”. His inventions have received international attention from major TV networks (Fox, CBS and 40 other local TV channels), radio stations (including NPR) and articles by Reuters and ASEE Morning Bell. He has also appeared in a PBS documentary in 2017 (Secrets of Spanish Florida) while discussing the impact response of ‘Coquina’, a material with which the oldest fort in the United States, the ‘Castillo de San Marcos’ was built in St. Augustine, Florida.

Organized by Profs Brice Lecampion & Alexandre Alahi
27/09/2019 @ 12:15 room GC B3 31

Microstructure sensitive strain-based modelling of fatigue life for high-performing steel structures

Prof. Heikki Remes, Aalto University, School of Engineering, Finland

Abstract:
A smooth weld geometry and only small imperfections are achievable using advanced manufacturing methods. And when crack-like imperfections are eliminated, increased fatigue life is expected because of the longer macro-crack initiation period. The modelling of this period is a challenge for the fatigue assessment of high-performing structures since conventional approaches only consider total fatigue life without distinction between crack initiation and propagation periods. To overcome this challenge, this presentation introduces a new microstructure sensitive strain-based fatigue life model. The model uses a cumulative fatigue damage model for the representative volume element (RVE), the size of which is defined from grain size statistics. In this way, the approach can model an arbitrary geometry shape and include the effect of material microstructure. By repeating the fatigue damage calculations for successive RVE steps, the model is also capable of modelling the fatigue damage process from the initial geometry up to the final fracture. Thus, the fatigue crack initiation, short crack growth and long propagation behavior are all considered as a continuous process in the same model. The introduced model is applied to various weld shapes, and the results are compared with experiments and existing local approaches.

Bio:
Heikki Remes graduated as Doctor of Science in 2008 from Helsinki University of Technology. Since 2014, he works as a Professor in Marine Technology at Aalto University, School of Engineering. He has special expertise in theoretical modelling and experimental testing of high-performing steel and marine structures. His research focus is on light and efficient structures that utilize high strength materials and modern manufacturing technology for challenging marine environment. He has been involved in several national and international research projects that aim for fundamental understanding of fatigue and fracture, as well as tackling practical challenges in the analysis production of high-performing structures. His research covers characterization and analysis methods for complex structures from crystal behavior to continuum modelling. He has published approximately 100 scientific journal and conference papers. He is a member in International Ship and Offshore Structures Congress (ISSC) and International Institute of Welding (IIW).

Organized by Profs Brice Lecampion & Alexandre Alahi
11/10/2019 @ 12:15 room GC B3 31

Ride-hailing, travel behaviour and sustainable mobility: Insights from a social welfare maximisation approach

Professor Alejandro Tirachini, Associate Professor of Civil Engineering, Universidad de Chile and Visiting Professor,Technische Universität München, Germany

Abstract
A discussion of the sustainability and travel behaviour impacts of ride-hailing (ridesourcing platforms such as Uber, Didi and Ola) is provided, based on current evidence from both developed and developing countries. The effects of ride-hailing on personal well-being, vehicle-kilometres travelled (VKT) and traffic externalities such as congestion are analysed. Then, a social welfare maximisation problem is developed, in order to determine the optimal number of vehicles and the optimal fare of a ride-hailing service. The solution is compared with the one that maximises private profit only. External costs of traffic are included into the social welfare framework. The optimal solution depends on two colliding forces: (i) users waiting time, that pushes to increase driver supply and (ii) the existence of negative traffic externalities, that pushes to reduce driver supply and increase fares. The problem is numerically solved including scenarios with conventional and automated cars for peak and off-peak traffic conditions.

Bio
Alejandro Tirachini (MSc UChile, PhD USydney) is Associate Professor of Civil Engineering at Universidad de Chile and Visiting Professor at Technische Universität München, Germany. His main research interests are the planning of public transport systems and the study of emerging mobility technologies. He has made contributions in the areas of optimal design of urban bus lines, estimation of crowding externalities in public transport in multiple cities, multimodal transport pricing, bus operations and congestion modelling, travel time variability modelling and the sustainability of ride-hailing. Apart from the research topic of this talk, currently he is working on analysing the social and traffic effects of a platform (app) for shared rides and the optimal design of automated public transport services in urban areas.

Organized by Profs Brice Lecampion & Alexandre Alahi
16/10/2019 @ 12:15 room GC B1 10

Management and Control of Complex Transportation Systems—a Multi Agent System Approach

Prof. Monty Abbas, Virginia Tech

Abstract:
Motivated by the need to manage a complex and evolving intelligent transportation system in a collaborative framework, we describe five components of multi-agent modeling paradigm with several implementation examples from the VT-SCORES research lab at Virginia Tech. The research components discussed range from driver behavior, car-following models, adaptive control, connected vehicles, and variable speed limit applications. We will show examples of extracting driver behavior from large datasets, modeling evolving system behavior with intelligent agents, integration of state estimation and communication frameworks in a connected vehicles environment, and the ramifications of neglecting learning in modeling. The presented agent-based framework is intermodal, and can incorporate performance characteristics and needs of different users (cars, trucks, busses, pedestrians, and bikes). We will also address emergency vehicles current and future applications and the impact of path-based priority tunnels provided for emergency vehicles in each application. The presentation will also touch on the latest innovations at the VT-SCORES lab and how it can help address evolving and complex transportation problems.

Bio :
Monty Abbas is a Professor in the Transportation Infrastructure and Systems Engineering at Virginia Tech. He holds a Doctor of Philosophy in Civil Engineering from Purdue University (2001). Dr. Abbas developed Purdue Real-Time Offset Transitioning Algorithm for Coordinating Traffic Signals (PRO-TRACTS) during his Ph.D. studies at Purdue University, bridging the gap between adaptive control systems and closed-loop systems. He has since developed and implemented several algorithms and systems in his areas of interest, including the Platoon Identification and Accommodation system (PIA), the Pattern Identification Logic for Offset Tuning (PILOT 05), the Supervisory Control Intelligent Adaptive Module (SCIAM), the Cabinet-in-the-loop (CabITL) simulation platform, the Intelligent Multi Objective Control Algorithms (I-MOCA), the Traffic Responsive Iterative Urban-Control Model for Pattern-matching and Hypercube Optimal Parameters Setup (TRIUMPH OPS), the Multi Attribute Decision-making Optimizer for Next-generation Network-upgrade and Assessment (MADONNA), the Safety and Mobility Agent-based Reinforcement-learning Traffic Simulation Add-on Module (SMART SAM), and the Broad Area-wide and Distance-wise Agent-based Signal-optimization System (BADASS). He was also one of the key developers of the dilemma zone protection Detection Control System (D-CS) that was selected as one of the seven top research innovations and findings in the state of Texas for the year 2002. He is a recipient of the Dean’s Award for Excellence in Service, ICAT Creativity and Innovation Day Process Award for the Traffic SONATA project, Best Paper Award, Western Decision Sciences Institute (WDSI) 2018 Conference, Oak Ridge National Lab Associated Universities (ORAU) Ralf E. Powe Junior Faculty Enhancement Award and the G. V. Loganathan Faculty Achievement Award for Excellence in Civil Engineering Education. He is also a recipient of the TTI/Trinity New Researcher Award for his significant contributions to the field of Intelligent Transportation Systems and Traffic Operations.

Organized by Profs. Brice Lecampion & Alexandre Alahi
25/10/2019 @ 12:15 room GC B3 31

Some Recent Advances and Perspectives in Catastrophe Risk Engineering for Multiple Natural Hazards

Dr Carmine Galasso, Associate Professor of Catastrophe Risk Engineering in the University College London (UCL), UK

Abstract:
Probabilistic catastrophe (CAT) risk models are becoming increasingly popular tools for estimating potential loss due to natural hazards, including earthquakes, windstorms, and floods. Such models incorporate detailed databases and scientific understanding of the highly complex physical phenomena of natural hazards and engineering expertise about how infrastructure, buildings, and their contents respond to those hazards.
This talk will present some recent advances in CAT modelling for earthquake and wind, namely: 1) the use of physics-based and stochastic ground-motion simulations for seismic hazard and risk modelling; 2) the development of a real-time CAT modelling framework for designing engineering applications of earthquake early warning; 3) the development of computational tools (e.g., advanced simulations, machine-learning techniques) for modelling risk to offshore wind energy; 4) the proposal of a probabilistic framework to assess wind-seismic interaction in typical structural details (i.e., connections) of tall steel buildings.
The talk will finally introduce and discuss some perspectives in CAT modelling for cascading and multiple hazards at different spatial scales (from a single asset to portfolio of buildings), with special focus on developing countries. In fact, developing countries are disproportionately affected by natural hazards and lack in coping capacities. CAT modelling for developing countries presents specific challenges in terms of quantity and quality of the available input data. Specifically, this talk will present some highlights of a number of current UCL projects on multi-hazard risk and resilience assessment of community-based infrastructure (e.g., schools, hospitals, heritage assets) in the Philippines, Indonesia, and China.

Bio:
Dr Carmine Galasso is an Associate Professor of Catastrophe Risk Engineering in the University College London (UCL)'s Department of Civil, Environmental & Geomatic Engineering (CEGE), UK, and a part-time Associate Professor of Structural Engineering at the Scuola Universitaria Superiore (IUSS) Pavia, Italy, in the Centro di Formazione e Ricerca per la Mitigazione del Rischio Sismico (ROSE School). Prior to joining UCL, Carmine has worked as a Catastrophe Risk Modeler at Applied Insurance Research (AIR) Worldwide, San Francisco, USA; and as a Postdoctoral Research Associate in the Department of Civil and Environmental Engineering, Performance-based Earthquake Engineering Laboratory, at the University of California, Irvine, USA. Carmine earned his PhD in Earthquake Risk at the Università degli Studi di Napoli Federico II, Italy, in January 2011.

Carmine’s research focuses on the development and application of probabilistic and statistical methods and tools for catastrophe risk modelling and disaster risk reduction. He is investigating risks to building portfolios and infrastructure exposed to multiple natural hazards, including earthquakes, strong wind, and flooding, with special emphasis on developing countries. He has authored >150 peer-reviewed papers and is/has been the PI on grants totaling £2M in the last three years. He is a key co-I of the newly funded £19.6 million Global Challenges Research Fund (GCRF) Urban Disaster Risk Hub, where he chairs the Risk Modelling Technical Activity Group. His research is funded by the UK Research Councils, the European Commission (Horizon 2020), the British Council, the Chinese International Centre for Collaborative Research on Disaster Risk Reduction (ICCR-DRR), the China Scholarship Council (CSC), the (Mexican) Consejo Nacional de Ciencia y Tecnología (CONACYT), the World Bank and its Global Facility for Disaster Reduction and Recovery (GFDRR), the Motorola Solution Foundation, and the Willis Research Network.

Organized by Profs. Brice Lecampion & Alexandre Alahi
08/11/2019 @ 12:15 room GC B3 31

CESS Seminar: Soil sorptive potential: unitary definition of matric potential

Professor Ning Lu, Colorado School of Mines, Colorado, USA

Abstract:
Despite the widely accepted notion that matric suction is the most fundamental variable for describing soil–water interactions in soil under unsaturated conditions, it is unable to describe several basic soil properties and behaviors such as pore-water pressure, soil water density, and phase changes of soil water. A variable with greater explanatory power, sorptive potential, is conceptualized as the origin of matric suction or matric potential and pore-water pressure. The soil sorptive potential is the sum of the locally varying electromagnetic potentials comprising van der Waals attraction, electrical double-layer repulsion, and surface and cation hydration. Local thermodynamic energy equilibrium dictates that the sorptive potential is always transformed or equal to matric potential minus the pressure potential within a representative elementary volume of matric potential. Limited verification was demonstrated by reducing the sorptive potential to the two well-established concepts of disjoining pressure and osmotic swelling pressure. Soil sorptive potential can be experimentally determined by the soil water retention curve. A parametric study was conducted to illustrate how soil and pore-fluid properties affect sorptive and pressure potentials, indicating that the pore-water pressure under unsaturated conditions can be as high as 0.6 GPa. Such locally high pore-water pressure is induced by the sorptive potential and provides an explanation for phenomena such as abnormally high soil water density, supercooling, and decreased cavitation observed in fine-grained soils.

Bio:
Ning Lu is professor of civil and environmental engineering at Colorado School of Mines (CSM) and the director of the joint CSM/US Geological Survey Geotechnical Research Laboratory in Golden, CO. He is a recipient of the ASCE 2007 Norman Medal, of the ASCE 2010 Croes Medal, of the ASCE 2017 Ralph B. Peck Award, and of the ASCE 2017 Maurice Biot Medal, as well as a fellow of ASCE, Engineering Mechanics Institute, and Geological Society of America. His primary research interests are flow and stress laws in multiphase porous media, rainfall-induced instability of natural and engineered slopes, geologic hazards, energy storage in porous media, and subsurface nuclear waste isolation. He is the senior author of the widely used textbook Unsaturated Soil Mechanics (John Wiley and Sons, 2004) and the textbook Hillslope Hydrology and Stability (Cambridge University Press, 2013).

Organized by Profs Brice Lecampion & Alexandre Alahi
14/11/2019 @ 09:30 room RLC A1 230

Publishers' license agreements : Welcome to hell!

EPFL Library teaching and publishing support team
Signing a contract with a publisher is supposed to be a rewarding step: your work is getting published! However, the understanding of a contract is less enjoyable, between very specialized terms and ambiguous sentences.
At the end of the workshop, you will be able to:
- Identify the key elements of a contract
- Understand the rights you keep and the ones you waive when you sign a contract
- Communicate with a publisher if you are willing to negotiate
15/11/2019 @ 12:15 room GC B3 31

CESS Seminar: Fracture propagation in brittle or embrittled materials as a standard dissipative process

Prof. Alberto Salvadori, DIMI, University of Brescia, Italy

Abstract:
Recent publications framed the problem of three-dimensional quasi-static crack propagation in brittle materials into the theory of standard dissipative processes [1, 2]. Variational formulations, stated therein, characterize the three-dimensional crack front quasi-static velocity as the minimizer of constrained quadratic functionals. An implicit in time crack tracking algorithm, that computationally handles the constraint via a penalty method was developed and implemented in [3]. Although the theoretical setting is sound, the derived crack tracking methods suffered from a major drawback that limited the interest in the method to its theoretical content. Speciﬁcally, the need of still currently unavailable accurate approximations for weight functions made the approach of minor interest from a numerical standpoint. Such a drawback was overcome in [4], where a viscous regularization of the fracture propagation in brittle materials as a standard dissipative process was formulated. Rate-dependency provided a simple and accurate approximation of the crack front velocity, thus allowing to formulate effective crack tracking algorithms. That idea is further developed here to model hydraulic fracture processes [5]. Although limited to a penny shaped crack benchmark, the novel set of differential equations that are here proposed are capable to model the evolution of the lag and of the crack advancing in a straightforward way. The formulation can be easily extended to account for fractures pressurized by gas or other substances.

[1] A. Salvadori. A plasticity framework for (linear elastic) fracture mechanics. J Mech Phys Sol. (2008)
[2] A. Salvadori and F. Fantoni. Minimum theorems in 3D incremental linear elastic fracture mechanics. Int J Frac (2013)
[3] A. Salvadori and F. Fantoni. Fracture propagation in brittle materials as a standard dissipative process: general theorems and crack tracking algorithms. J Mech Phys Sol. (2016)
[4] A. Salvadori, P.A. Wawrzynek, and F. Fantoni. Fracture propagation in brittle materials as a stan dard dissipative process: Effective crack tracking algorithms based on a viscous regularization J Mech Phys Sol. (2019)
[5] E. Detournay. Mechanics of hydraulic fractures. Ann. Rev. Fluid Mech. (2016)

Bio:
Prof. Alberto Salvadori received his M.S. in Civil Engineering from the University of Brescia in 1995 and Ph.D. degrees in Engineering Science from Politecnico di Milano, in 2000. At present, he is Associate Professor at the University of Brescia. He has been Research Assistant Professor at the University of Notre Dame, USA from Jan. 2015 to June 2017. He was also recipient of a Marie-Curie IEF fellowship, that he spent at the Technical University of Eindhoven (The Netherlands). He founded the Multiscale Mechanics and Multiphysics of Materials Lab and is currently Director of the CeSiA (Centro di Studio e Ricerca di Sismologia applicata e dinamica strutturale - Applied Seismology and Structural Dynamics Research Center) at the University of Brescia. Professor Salvadori's research is focused on the multiscale and multiphysics modeling in the green and white economy, as well as on understanding of failure in continua. He is particularly interested in Mechanobiology, energy-storage materials, (computational) homogenization, diffusion and migration of species in solids and in the induced fracturing processes (especially for Li-ion batteries modeling, Hydrogen Embrittlement in metals, Environmentally assisted cracking, Solid Oxide Fuel Cells, Hydraulic fracturing and gas/oil shale extraction), variationally modeled in two- and three-dimensions via standard dissipative systems and approximated via ad-hoc numerical schemes.

Organized by Profs Brice Lecampion & Alexandre Alahi
22/11/2019 @ 12:15 room GC B3 31

CESS Seminar - Recruiting structural optimization to the seismic design process

Dr. Oren Lavan, Associate Professor, Technion Israel Institute of Technology

Abstract:
Over the past three decades, there has been a significant shift in the approach to structural design under dynamic loadings. Many new technologies associated with passive energy dissipation and control have been introduced and have reached a considerable level of maturity. Furthermore, the concept of performance-based design and financial loss considerations have gained prominence. While all of this represents a major step forward, as a consequence, the design process itself has become increasingly complex.
The aim of this talk is to discuss the potential role of structural optimization in the seismic design process. This will be done while presenting ongoing research in which the presenter has been involved. The research is focused on various optimal design methodologies using various types of energy dissipation devices. Particular attention is given to the importance of a meaningful optimization problem formulation, the value expected from utilizing optimization, the importance of tailoring an appropriate optimization algorithm for a given problem, and the potential of using optimization in practical design.

Bio:
Dr. Oren Lavan is an Associate Professor in the Faculty of Civil and Environmental Engineering at the Technion – Israel Institute of Technology. He received his Ph.D. in Civil Engineering from the Technion in 2006, and was a Visiting Research Scientist (2005-2007) at the Department of Civil, Structural and Environmental Engineering, University at Buffalo – The State University of New York. He spent a sabbatical as a Visiting Associate Professor at the Disaster Prevention Research Institute at Kyoto University (2014). Dr. Lavan teaches and conducts research in structural dynamics, structural optimization, earthquake engineering, structural control, progressive collapse prediction and computational mechanics. He has published extensively in the area of structural engineering and mechanics, including more than forty five peer-reviewed articles in premier journals in the field.

Organized by Profs. Brice Lecampion & Alexandre Alahi
26/11/2019 @ 18:30 room CM 1 121

Quantum light correlations for data processing

Dr. Anna Pogrebna

The EPFL Photonics Chapter (EPC) is very pleased to announce and cordially invite you to our monthly ‘Pizza-Optics-Beer’ (POB) seminar on November 26th, at 18:30 in the room CM 1121.

This month we will have the pleasure to host Anna Pogrebna, Post-doctoral Researcher in the Laboratory of Quantum Nano-Optics (LQNO), with the presentation entitled:

"Quantum light correlations for data processing”

For organizational purposes (if you want to eat pizza!), please confirm your participation using this Doodle.

Don’t hesitate to extend the invitation to any postdoc and colleague!

Hope to see you there,
The team of the EPFL Photonics Chapter

Abstract:

While the information industry based on Moore’s law hits its development limit, fundamentally new principles for information processing and data storage need to be discovered and implemented. One promising technology is a quantum computing, that could spur the development of new breakthroughs in science. I would like to present the quantum optic experiments we are performing in our lab. Just recently we have demonstrated that the sub-picosecond dynamics of quantum phonons can be measured at room temperature. I will show the most recent results and discuss the future of the data storage technology in general.

Organized by EPFL Photonics Chapter
29/11/2019 @ 12:15 room GC B3 31

CESS Seminar: How moving cracks in brittle solids choose their path

Prof. Jay Fineberg, the Racah Institute of Physics, the Hebrew University of Jerusalem

Abstract:
While we have an excellent fundamental understanding of the dynamics and structure of cracks propagating in brittle solids, we do not fully understand how the path of a moving crack is determined. Here we experimentally study cracks that are propagating between 10-95% of their limiting velocity within a brittle material. We deflect these cracks by either allowing them to interact with sparsely implanted defects or driving them to undergo an intrinsic oscillatory instability in defect-free media. By dense measurements of the strain fields surrounding the crack tips via high speed imaging, we determine what governs a crack’s direction when it is strongly deflected. We reveal that the paths selected by these rapid and strongly perturbed cracks are entirely governed by the direction of maximum energy density and not by the oft-assumed principle of local symmetry. This fundamentally important result may potentially be utilized to either direct or guide running cracks.

Bio:
Pr. Jay Fineberg is professor at The Racah Institute of Physics, The Hebrew University of Jerusalem. Pr. Jay Fineberg’s laboratory has a variety of different research interests. Each of these projects is interesting in itself, fundamentally important, an intrinsically nonlinear process. Some of these, in broad strokes, are: (i) the physics of dynamic (rapid) fracture in brittle materials, (ii) the pattern formation and interactions of nonlinear waves, and (iii) the physics of the onset of frictional motion and laboratory modeling of earthquakes. Prof. Fineberg has published over 100 research articles in the leading journals in the sciences and Physics. 16 of his papers have been published in Nature or Science magazines and about 40 in the Physical Review Letters.

Organized by Prof. Brice Lecampion & Prof. Alexandre Alahi
06/12/2019 @ 12:15 room GC B3 31

CESS Seminar: Assessing the Role of Immigration Policy for Foreign Students: the Case of Campus France

Prof. Michel Beine, University of Luxembourg

Abstract:
This paper studies the intended and unintended effects of a specific policy conducted by the French Government around 2006 aiming at boosting the number of foreign students admitted in French universities. The Campus France program aimed at facilitating the application process of foreign candidates from some particular countries and applying in specific universities. We develop a small theoretical model that allows for the existence of capacity constraints in order to analyse the potential effects of such a policy in terms of student inflows and in terms of selection. Using a Diff-in-Diff-in-Diff approach, we test the impact of Campus France on the magnitude of inflows. We find that the Campus France policy led to a global increase of inflows of foreign students around 8%. The increase is concentrated on universities outside the top 150 of the Shanghai Ranking. We also use the CF policy as a way to test the potential crowding-out effects on native students while taking care of the usual endogeneity concerns. We find some evidence in favour of crowding-in effects, either on native students or on foreign students coming through the traditional channel.
Joint paper with Lionel Ragot (Univ Paris X).

Bio:
Michel Beine has been a professor of economics at the University of Luxembourg for more than 10 years and is a research fellow of IZA (Bonn), CES-Ifo (Munich), IRES (Louvain) and CREAM (London). His current research focuses on the economic issues related to international migration, such as brain drain, international mobility of students, climate change and migration and determinants of international migration. He has published more than 50 papers in academic journals, such as Economic Journal, Journal of Development Economics, European Economic Review, Review of Urban and Regional Economics, Canadian Journal of Economics or Scandinavian Journal of Economics or the Journal of Economic Geography. His work has received more than 7500 citations with a h-index of 39 (Google scholar). He is currently the coordinator of the PRIDE MINLAB doctoral program on topics involving migration, labour and inequality. He has been acting as an adviser of several international institutions such as the World bank, the European Commission, Industry Canada, the Walloon Region in Belgium or the Banque de France.

Organized by Prof. Brice Lecampion & Prof. Alexandre Alahi
10/02/2020 @ 09:30 room UNIL Génopode, Auditorium 10

Lausanne Genomics Days 2020

Prof. Martin Jinek Dr. Robertas Ursache (Prof. Niko Geldner lab) Dr. Lotte Spel (Prof. Fabio Martinon lab) Prof Detlev Arendt Prof. Anne Roulin Prof. Stefan Ameres Dr. Flora Brozzi (Prof. Romano Regazzi lab) Dr. Rodrigo Siqueira Reis (Prof. Yves Poirier lab) Lina Worpenberg (Prof. Jean Yves Roignant lab) Prof. Colin Hill Dr. Kirsten Ellegaard (Prof. Philipp Engel lab) Paddy Gibson (Prof. Jan-Willem Veening lab) Dr. Guillem Salazar Guiral Prof. Tamir Tuller Dr. Anneke Brümmer (Prof. Sven Bergman group) Dr. Cedric Gobet (Prof. Felix Naef lab) Prof. David Gatfield

Lausanne Genomics Days 2020 is an annual event sponsored by the University of Lausanne and the Conférence Universitaire de Suisse Occidentale (CUSO).

This 2-day event will bring to Lausanne internationally renowned investigators to present and discuss the newest developments in genomics and genomic technologies and their impact on biological research. The format of the event has been updated in 2020, introducing presentations from UNIL laboratories, the objective being to share, stimulate the usage of, and promote the development of cutting edge genomics methods for the benefit of the whole UNIL and EPFL community.

Organized by Dr. Julien Marquis, UNIL Prof. Julia Santiago Cuellar, UNIL Prof. Philipp Engel, UNIL Prof. Tanja Schwander, UNIL Prof. Sven Bergmann, UNIL
28/02/2020 @ 12:15 room GC B3 30

CESS Seminar: Building with mushrooms

Prof. Lars De Laet, Department of Architectural Engineering, Vrije Universiteit Brussels (Belgium)

Abstract:
The construction industry is the largest consumer of natural resources worldwide and, moreover, responsible for the largest waste flows in Europe. The research conducted by professor Lars De Laet and his colleagues from the VUB Architectural Engineering research group aims to contribute to reducing the construction industry's environmental footprint. During his lecture, Lars will present how they work towards these objectives by focusing on new design methodologies, by developing efficient structural systems and by investigating new biomaterials based on fungi.

Bio:
Lars De Laet is Associate Professor at the Department of Architectural Engineering at the Vrije Universiteit Brussel, Belgium, where he was appointed in October 2013 as professor to conduct research in the field of architectural and structural design of resource efficient structures.

Being educated as an architectural engineer, Lars develops with his team lightweight structures, biological building materials and computer-assisted design methods for sustainable architecture and infrastructure. They develop computational tools for structural design and form finding, and focus on full-scale prototyping employing new (bio)materials, digital and robotic fabrication technologies and large-scale experimental testing.

Lars is involved in national and European research projects. He was co-chair of the European COST-Action on ‘Novel Structural Skins’ and is a member of various international associations, such as the International Association for Shell and Spatial Structures (IASS) and TensiNet. In addition, Lars has been vice-chair of the board of directors of the VUB, where he is currently a member of the university council. Lars has been elected in 2019 as a member of the Young Academy, part of the Royal Flemish Academy of Belgium for Science and the Arts.

Organized by Prof. Brice Lecampion (GEL) & Prof. Alexandre Alahi (VITA)
06/03/2020 @ 12:00 room GC B3 30

"Planning of Underground Space"

Antonia Cornaro, MA Urban Planning (1996), studied communications, social sciences (BA) and Urban Planning (MA) at New York University. She has over 20 years of working experience as an urban and transport planner from the public and private sector in New York City, London, Vienna and Zurich, having worked for NYC Department of City Planning, WSP, and the Austrian Institute of Regional Planning. In her current work as Expert and Business Developer for Amberg Engineering, an international Swiss-headquartered firm specializing in underground infrastructure design and management, she focuses on Underground Space with the aim to increase mobility, livability and resilience of urban areas. This is also central to her work as Co-Chair of ITACUS[1]. Passionate about cities, global and sustainable development, Antonia has presented and published extensively on this subject. Together with Han Admiraal she has published the book "Underground spaces unveiled: planning and creating the cities of the future"[2]. As part time lecturer for the spring semester 2020 at ETHZ she holds a semester lecture on the planning of underground space, offered to Master students in Civil Engineering and Spatial Planning[3]. [1] the International Tunnel and Underground Space Association's Committee on Underground Space, http://ita-aites.org/ [2] more info: www.thinkdeep.net [3] https://tunnel.ethz.ch/en/

short abstract
•Underground space is a major strategic asset of cities worldwide
•In ensuring our development efforts happen in a sustainable way, we need to plan and optimise the underground development
•That way underground space can help achieve several of the 17 Sustainable development goals as defined by the U.N.
•It can also make our cities more resilient and able to withstand shocks and stresses facing us

Organized by Prof. Brice Lecampion et Prof. Alexandre Alahi
01/04/2020 @ 09:30 room RLC A1 230

Smart Publishing

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:

• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Know and protect your rights as an author according to EPFL’s policy
• Ensure your compliance towards EPFL and funders Open Access policy

Organized by EPFL Library
19/10/2020 @ 00:01 room

Open Access Week 2020

As every year, the EPFL Library is pleased to contribute to the international scholarly communication event Open Access Week.

This year, the Library's Publishing Support team is proud to share new concrete tools to help EPFL researchers and the scientific community in their publishing related activities and their Open Access issues. Discover the Publishing Support Fast Guides: 6 guides, which will give you basic and advanced information about Open Access, scientific publishing, copyright, citation, etc.

Do not hesitate to contact the Library's Publish Support team at publishsupport@epfl.ch ! Find all information about the Library Publishing Support services on https://go.epfl.ch/publishing-support

Organized by EPFL Library
27/10/2020 @ 12:15 room ZOOM

EESS talk on "Flow and Transport in the Natural Environment and Agroecosystems: Advances and Applications in Soil, Water, Energy and Food Systems"

Dr Christophe Darnault, Associate professor, Department of Environmental Engineering and Earth Sciences, College of Engineering, Computing and Applied Sciences, Clemson University (USA)

Abstract:
Understanding flow and transport processes in the natural environment and agroecosystems is critical for the sustainable exploitation and management of natural resources —soil, water, forests, and fossil fuels, the development of effective remediation procedures, and the protection of the human and ecosystem health. Our research on the soil and water conservation in agricultural and forestry systems investigates the impacts of water reuse and prescribed fires practices on the surface and subsurface processes —hydrology and soil erosion, and water quality within this landscape. We studied the spatial distribution and morphometry of closed depressions change over time in a wastewater spray irrigated karst landscape with bedrock fractures, and modeled the groundwater flow and nitrate transport in the karst aquifer resulting from the recycling and reuse of wastewater by irrigation of agriculture and forestry lands for enhanced groundwater recharge of a karst aquifer. Our research on post-fire effects on hydrological and geochemical processes in soil from forest of the Southeastern United States established the soil physico-chemical and hydraulic properties of unburned and burned soils and how these properties relate to infiltration and water repellency phenomena as well as sorption behaviors of polar and nonpolar compounds. The release of emerging contaminants, such as engineered nanomaterials, into the environment; the prevalence of microbial pathogens (Cryptosporidium parvum and Toxoplasma gondii) in the soil and water systems; and the discharge of radionuclides (uranium) during storage, handling, and disposal of nuclear materials in groundwater are inevitable. To study the fate and transport of these contaminants in the subsurface, we have investigated their mobility under different hydrodynamic and biogeochemical conditions found in the environment. We have demonstrated the critical role that preferential flow; transient water content, velocity, and chemistry, gas-water and solid interfaces; system heterogeneities; plants and microbes; and their interactions and feedback have in the flow and contaminants behavior. Mobilization of crude oil is essential for the exploitation of petroleum reservoirs. We have explored the ability of nanoparticles (silica nanoparticles) to improve the efficiency of the chemical-enhanced oil recovery process that uses surfactant flooding by examining interfacial and rheological properties of multiphase systems and sandstone-crude oil-nanofluid systems. Our research results will contribute to the development and validation of flow, fate, and transport models of contaminants from pore scale to watershed scale for management and protection of soil and water resources, petroleum reservoirs, public health, ecosystem sustainability, risk assessment, and life-cycle analysis.

Short biography:
Christophe Darnault is Associate Professor at the Department of Environmental Engineering and Earth Sciences at Clemson University. He is the Chair of the South Carolina Section of the American Society of Agricultural and Biological Engineers. He serves as Associate Editor for Frontiers in Environmental Science – Soil Processes, Frontiers in Earth Science, section Soil Processes, and served as Associate Editor for the Journal of Hydrology (Elsevier). He has research and teaching experience at Rensselaer Polytechnic Institute and University of Illinois at Chicago. He was also a visiting scholar at Yale University. He received his Ph.D. in Environmental and Water Resources Engineering from Cornell University, and his combined M.S. & B.S. degree (Diplôme d’Ingénieur) in Agricultural, Environmental, and Biological Engineering from the Institut Supérieur d'Agriculture, Lille, France (1995). Dr. Darnault’s teaching and research interests are in the fields of environmental health and engineering/bioengineering, agricultural and biological engineering, hydrological sciences, hydraulic engineering, and soil and water resources engineering and management.

Organized by EESS - IIE
17/11/2020 @ 10:00 room Online

Coffee Lecture #03: Unpaywall: find Open Access content easily

EPFL Library
- Watch the podcast on YouTube
- Presentation available here
Coffee lectures are 15-minutes sessions where practical information (tools, tips) about various topics (research data, information search, copyright) is presented. Grab your cup of coffee (or tea) and join us!

For this coffee lecture, the learning objective is:

- Discover how to search for Open Access versions of research papers
Organized by EPFL Library
18/11/2020 @ 09:30 room Online

Smart Publishing - online course in two parts

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:

Part I, November 18, 9.30am-11.30pm
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders Open Access policy

Part II, November 20, 10.30am-11.30pm
• Know and protect your rights as an author according to EPFL’s policy

Organized by EPFL Library
18/11/2020 @ 10:00 room Online

Smart Publishing - online course in two parts

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:

Part I, May 19, 10am-12pm:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders Open Access policy

Part II, May 20, 11am-12pm:
• Know and protect your rights as an author according to EPFL’s policy

Organized by EPFL Library
15/06/2021 @ 09:30 room Online

Smart Publishing - course in two parts

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:

Part I, June 15, 09:30 am - 11:30 am:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders Open Access policy

Part II, June 16, 10:30 am - 11:30 am:
• Know and protect your rights as an author according to EPFL’s policy

Organized by EPFL Library
08/07/2021 @ 14:00 room

Open the Door to Your Publications

Beatrice Marselli (STI Liaison, EPFL Library)
Is it open access compatible to have all my publications available on ArXiv? Do you want to publish open access but cannot find any suitable journals in your field? Do your open access publications cost you a significant amount of money that can be invested somewhere else? Are all these colours of open access more confusing than helpful? Are funders’ OA requirements limiting your possibilities to publish? Do you find open access too complex to navigate in? You have no idea where to turn for help and support?

Open Access is a complex area to navigate in and there are many open questions. During this webinar, you will deep dive into open access publishing to get accustomed to a handful of information, tools, and practices that will enable you to master open access in no time. You will learn :
- What open access is and why it is a topic for a seminar
- How you can make your paper, your book or any other publication open
- When and how to plan for open access
- Understand your rights as an author
- Bust common myths of open access
- What is required by EPFL and by funders
- What financial and non-financial support is available for you
The presentation will be followed up by discussing the current challenges of the open access domain and hidden opportunities to open your publications to the wider public.
Organized by Miriam Braskova (STI Open Science Coordinator)
25/10/2021 @ 12:00 room EPFL Campus

Open Access Week 2021

EPFL Library Publish Support Team

In the frame of the international event Open Access Week 2021 (October 25-31), the EPFL Library invites you to join daily events on site and online to celebrate Open Access.

PROGRAM

Monday, Oct. 25 | 12PM-1PM
Stand on EPFL campus (replaced by a Zoom Q&A if COVID regulations strengthened)
OPEN ACCESS DAY
Stop by the Library’s booth at the Méridienne to talk about Open Access
Join the Library's Publishing Support team to kick off Open Access Week and its program of events and ask all your questions about Open Access and publications.

Tuesday, Oct. 26 | 12PM-1PM
Zoom Q&A | https://epfl.zoom.us/j/65357825180
OPEN ACCESS COMPLIANCE
Online demo of the tool Open Access Compliance Check Tool
Join this online event to discover the new Open Access Compliance Check Tool (OACCT) that will guide you in deciding where and how to publish your research in agreement with funders’ and institutional Open Access policies. We're making the road to compliance easier for you.

Wednesday, Oct. 27 | 12PM-1PM
Stand on EPFL campus (replaced by a Zoom Q&A if COVID regulations strengthened)
CREATIVE COMMONS LICENSE
Stop by the Library’s booth on the Esplanade to learn how to choose an open license
You are not sure what licenses are better for publishing your article, code or dataset? How to assign them? What they really allow? Come at the Esplanade to talk open licenses with the Library.

Thursday, Oct. 28 | 12PM-1PM
Zoom Q&A | https://epfl.zoom.us/j/65357825180
OPEN EDUCATIONAL RESOURCES
Join to learn and discuss about OER
Have you ever heard about Open Educational Resources (OER)? Join this online event to learn more and consider how it could apply for your future teaching and training activities.

Friday, Oct. 29 | 12PM-1PM
Zoom Q&A | https://epfl.zoom.us/j/65357825180
ORCID
Online demo of ORCID and the EPFL integration
What is an ORCID id? Why would you need one and how can you use it efficiently? These and other questions will be answered during this online demo by the Publish Support team.

_______________

Do not hesitate to contact the Library Publish Support team at publishsupport@epfl.ch !
Find all information about our services on https://go.epfl.ch/publishing-support.

Organized by EPFL Library
03/11/2021 @ 09:30 room tbc

Smart Publishing - course in two parts

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:

Part I, June 15, 09:30 am - 11:30 am:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders Open Access policy

Part II, June 16, 10:30 am - 11:30 am:
• Know and protect your rights as an author according to EPFL’s policy

Organized by EPFL Library
09/11/2021 @ 12:15 room

EESS talk on "Rational Design and Process Evaluation of Aqueous-phase Advanced Oxidation Processes"

Dr Daisuke Minakata, Associate Professor, Department of Civil, Environmental, and Geospatial Engineering, Michigan Tech University (USA) and EAWAG Visiting Professor

Abstract:
The identification of trace organic contaminants in natural waterways and during water and wastewater treatment processes has raised public concerns about the uncertain adverse effects to human health and ecosystems. Advanced oxidation and reduction processes that produce highly reactive radicals such as hydroxyl radicals and solvated electrons at room temperature and atmospheric pressure are attractive and promising methods that can destroy a wide variety of reduced and oxidized forms of organic contaminants. Reactive radical species rapidly reacts with water constituents and target contaminants to initiate a series of radical-involved chain reactions that lead to various intermediates and transformation byproducts. Although a number of experiments and kinetic models have revealed the major reaction pathways for some contaminants, the fate of the transformation byproducts has not yet been elucidated.
In this talk, I will present the fundamentals science of advanced oxidation processes and process rational with applications. I will also cover research projects on advanced oxidation and reduction processes I have conducted in the last 20 years.

Short biography:
Dr. Minakata is an associate professor in Environmental Engineering at Michigan Tech. Dr. Minakata earned Ph.D. degree in Environmental Engineering at Georgia Institute of Technology in 2010 and M.S. and B.S. from Kyoto University in Japan. After he earned Ph.D., he worked as a research engineer at the Brook Byer Institute of Sustainable Systems at Georgia Tech for 3.5 years and in 2013 Dr. Minakata joined CEE department at Michigan Tech. Since 2020, he has been promoted to associate professor. In 2021-2022, Dr. Minakata is spending his sabbatical at Eawag working on ozonation and chemical oxidation processes with Professor Urs von Gunten.

Organized by EESS - IIE
07/12/2021 @ 12:15 room

EESS talk on "The chemical composition of the interface of (some) atmospheric particles: A molecular view"

Dr Michel Rossi, Emeritus Senior Scientist, Group Ludwig, EPFL

Abstract:
A flowing gas experiment is used to “interrogate” the gas-solid interface of specific atmospheric particles using reactive probe gases that interact to various extents with surface functional groups making up the interface.
For instance, a basic probe gas such as trimethylamine may interact with surface acidic functional groups such as carboxylic acids or acidic OH groups in a neutralization reaction. We will first explain the advantages and disadvantages of the used method based on molecular beam sampling mass spectrometry and subsequently present three examples that describe applications of the method to atmospheric chemistry: (a) the interface of amorphous carbon generated from incomplete combustion/oxidation processes or biomass burning has a wealth of surface functional groups revealing both its provenance as well as past atmospheric processing. More often than not the interface has both acidic and basic as well as oxidizing and reducing properties side-by-side;
(b) The atmospheric fate of semivolatile organic compounds that are partially oxidized is subject to the presence of secondary organic aerosols and atmospheric mineral dust particles. We will undertake a brief tour of the heterogeneous interaction of three partially oxidized semivolatile compounds with two proxies of mineral dust particles (Kaolinite, Arizona Test Dust) in terms of adsorption and desorption kinetics. We will highlight the relationship between organic structure and abundance of surface functional groups of the mineral dust proxy; (c) the interfacial composition of an atmospheric particle greatly controls the role it plays in oxidative stress on living organisms in terms of supporting Reactive Oxygen Species (ROS) through interfacial reactions in the presence of atmospheric oxygen. Laboratory experiments using antioxidants in solution correlate with the abundance of redox-cycling surface functional groups. It turns out that the interface acts as a redox catalyst in order to accelerate surface oxidation in the presence of excess atmospheric oxygen.

Short biography:
PhD in physical chemistry (University of Basel, 1975). postdoctoral fellow at Stanford Research Institute (SRI International, 1976-78); Swiss National Science Foundation fellowship (1979); rose through the ranks of Stanford Research Institute to end up as program manager/senior scientist in the Chemical Kinetics Department/Physical Sciences Division (1991); adjoint scientifique and chargé de cours at EPFL/DGR, Laboratoire de Pollution Atmosphérique et Sol (LPAS), in charge of the heterogeneous atmospheric chemistry program (1991-2008); senior scientist at PSI in the Laboratory of Atmospheric Chemistry (LAC/ENE) (2009- 2019); guest scientist at EPFL since 2017 maintaining a level of scientific activity in the GR-Lud/IIE Department to date.

Organized by EESS - IIE
10/12/2021 @ 12:15 room GC B1 10

The Croation Centre for Earthquake Engineering - from oblivion to essential need

Prof. Josip Atalić, Associate Professor, University of Zagreb, Croatia

The Republic of Croatia is among the most earthquake-prone countries in Europe, yet the activities related to assessment of potential earthquake risk and its reduction can be characterized as individual and insufficient. The last paragraph of a paper published just before the earthquake in Zagreb gives perhaps the best pre-earthquake perspective (oblivion phase):
‘’It can be concluded that the present level of awareness about our own exposure and vulnerability to earthquakes in Croatia is not sufficiently developed to serve as a basis for compelling efforts to foster institutionalized seismic risk assessment, mitigation and preparedness activities. In fact, it seems that the relatively low probability of occurrence of strong earthquakes, when compared to natural and other disaster hazards, contributes to a pervasive ignorance of the fact that earthquakes constitute an unacceptable risk (officially). It is therefore essential to act without delay as, unlike some other countries, we still have time to react before another potentially disastrous earthquake strikes in Croatia.’’

Short Bio :
Josip Atalić is the Associate Professor in the Department of Engineering Mechanics of Faculty of Civil Engineering University of Zagreb. His areas of research are earthquake engineering, historical structures, numerical modelling, seismic risk etc. Josip participated in several research projects, published over 50 scientific papers, he is a peer reviewer for national and international journals and participated in over 150 (led over 50) professional work projects (structural designs). He is the leader of the team of experts for National Risk Assessment in Republic of Croatia - Seismic Risk, risk management capability assessment and national strategy in cooperation with the National Protection and Rescue Directorate (NPRD) and Ministry of Construction and Physical Planning of Republic of Croatia (2014-2021). He participates in Study on Seismic Risk Mitigation in the City of Zagreb in collaboration with the Zagreb City Office of Emergency Management from 2013-2021 (leader in 2016, 2017 and 2020). Josip is a part of Croatian Civil Protection MUSAR team, and he is a member of Thematic Working Group for the Security in National Development Strategy by 2030. After the earthquakes in Croatia in 2020, Josip led the organization of damage assessments and reconstruction cost assessment (for Government and World Bank), he is author of two books/guidelines for reconstruction process and participated in numerous strategic activities on the state level. He is leader and one of the founders of Croatian Centre for Earthquake Engineering.

Organized by Prof. Dr Katrin Beyer
10/12/2021 @ 12:45 room GC B1 10

Building damage caused by devastating earthquakes in Croatia in 2020

Prof. Mario Uroš, Associate Professor, University of Zagreb, Croatia

The paper will present the basic characteristics of the earthquakes that hit Croatia in 2020 from a structural engineering point of view. Characteristic damage to typical buildings in the affected regions will be shown depending on the magnitude of the earthquake. Numerous examples will provide an overview of the causes of damage to structural and non-structural elements. The impact of earthquakes of different magnitudes on the response of buildings will be compared.
In the paper, the mechanisms of collapse of masonry buildings depending on the existence of diaphragms and their connection to the walls will be described. Also, observed extension of damage will be compared to that expected damage level for earthquakes of this magnitude.
Finally, conclusions will be given about the causes of the damage and the measures that need to be taken to prevent them in the future. Special attention will be given to the load bearing capacity and ductility of masonry buildings, their ability to dissipate energy and the failure mechanisms that are crucial for damage of buildings.
Short Bio :
Mario Uroš was born in 1982 in Dubrovnik. He studied at the Faculty of Civil Engineering in Zagreb, where he graduated in 2006 in the field of structural engineering. Now, he works at the Faculty of Civil Engineering, University of Zagreb as an Associate Professor at the Department of Engineering Mechanics, Chair for Statics, Dynamics and Stability of Structures. He is actively involved in teaching of the university undergraduate and graduate programs at the in courses Mechanics II and Theory of Stability.
In his scientific work he works in the wider field of numerical modeling, dynamics and stability of structures and earthquake engineering. He participates in the many scientific project in his field of research as a participant or leader. He is a member of the organizing and scientific committee of several scientific and professional international conferences and author of many relevant scientific and professional papers.
He was involved in the implementation of European projects MATILDA for damage assessment and emergency measures after earthquakes and Interreg READINESS project in which he performs numerical calculations for buildings of strategic interest in the City of Dubrovnik and Split-Dalmatia County in case of a possible earthquake, in cooperation with the Faculty of Civil Engineering and the Faculty of Science. As a member of the working group of the Faculty of Civil Engineering, which was the main contractor in cooperation with DUZS and MGIPU during 2018, he worked on the preparation of the Updated Disaster Risk Assessment for the Republic of Croatia - earthquake risk assessment. He is a member of the team for the preparation of the Earthquake Remediation Study, which has been conducted for the City of Zagreb since 2012, and in 2018 he was the leader of the team. He was a member of the Croatian team for post-earthquake damage assessment, mobilized through Civil Protection of the Ministry of the Interior, on the mission in Albania after the earthquake in 2019. He is currently the head of the Establishment Research Project of the Croatian Science Foundation "New vulnerability models of typical buildings in urban areas: applications in seismic risk assessment and target retrofit methodology"
He is a member of the subcommittee HZN/TO 548/PO 8, Construction Eurocodes; Eurocode 8, Design of seismic resistance of structures in the Croatian Standards Institute. He is a member of the editorial board of the scientific journal Građevinar and is a reviewer for several scientific journals. Since 2011 he has been a member of the Croatian Chamber of Civil Engineers. He has been one of the coordinators of rapid damage assessments of buildings by civil engineers after the earthquakes in Zagreb in March 2020 and Petrinja in December 2020 and a series of necessary community relief activities. He has won several awards, including the Medal of the City of Zagreb and the award of the Croatian Chamber of Civil Engineers "Kolos" in 2020 for his contribution to post-earthquake activities.

Organized by Prof. Dr Katrin Beyer
01/03/2022 @ 12:15 room GC B1 10

EESS talk on "Spatial processes shape biodiversity patterns in river networks"

Dr Luca Carraro, Postdoctoral researcher, Department of Aquatic Ecology, EAWAG

Abstract:
Freshwater environments are particularly rich in biodiversity, hosting about 10% of the known animal species, despite occupying only 2% of the global water surface. However, global change is posing serious threats to biodiversity, with effects on freshwater environments that are reportedly more severe than is the case for terrestrial or marine habitats. This calls for the development of adequate tools for freshwater biodiversity assessment at high spatiotemporal resolution, which must be based on an appropriate description of riverine landscapes, their connectivity structure, and the hydrological drivers that affect local abiotic conditions and dispersal processes. In this talk, I will present a suite of modelling approaches to study spatial ecohydrological processes in river networks, and specifically: i) The generation of virtual analogues of river networks (so-called Optimal Channel Networks) that share the same topological and scaling features of real rivers; ii) The relationship between riverine connectivity patterns and metrics defining stability and persistence of a metapopulation; iii) A meta-ecosystem perspective on the spatial distribution of riverine communities; iv) A hydrology-based model for transport of environmental DNA (eDNA, i.e., molecular traces of organisms sampled from stream water) that allows assessment of highly resolved riverine biodiversity patterns. All of these approaches are linked by a substantial unity of methodologies, which ultimately shows the crucial role exerted by hydrological processes in shaping ecological communities in river networks.

Short biography:
After a B.Sc. and M.Sc. in Civil and Hydraulic Engineering at the University of Padua (Italy), Luca Carraro obtained a Ph.D. in Civil and Environmental Engineering at EPFL in 2018. There, he worked at the interface of hydrology, ecology and epidemiology, especially focusing on the epidemiological modelling of a disease (proliferative kidney disease) lethal to salmonid fish. Subsequently, he moved to Eawag (Dübendorf, Switzerland) for a postdoctoral fellowship at the Department of Aquatic Ecology (jointly funded by the University of Zurich), where he has been mostly focusing on the development of environmental DNA transport models in rivers. As of July 2022, he will start an SNF Ambizione fellowship at the University of Zurich, where he will expand his research coupling hydrological and ecological models to enhance the assessment of riverine biodiversity patterns.

Organized by EESS - IIE
07/03/2022 @ 18:00 room SG 1212

Do Not Carry Your Flag Too Low / ARCHIZOOM

Tiago Borges, Teresa Cheung, Silvia Groaz, la-clique, Trojans

Actions from Matrix Feminist Design Co-operative

Opening Monday 7 March, 6 p.m.

An exhibition about the inclusiveness of our buildings and common spaces, showing the archive of the radical 1980s feminist architecture practice Matrix. This work explored issues about community and the built environment, and traced the implications of feminist theory and critique on architecture and urban design.

The exhibition will also host the DRAG(UE) teaching unit, the reconstructed furniture of Berta Rahm's pavilion by ANNEXE, as well as workshops for children organized by the Science Promotion Service at EPFL.

Curated by Tiago P. Borges, Teresa Cheung, Silvia Groaz and the collectives la-clique and Trojans.

Organized by Archizoom
Tiago Borges, Teresa Cheung, Silvia Groaz, la-clique, Trojans
07/03/2022 @ 18:00 room SG 1212

OPENING : DO NOT CARRY YOUR FLAG TOO LOW

Tiago P. Borges, Teresa Cheung, Silvia Groaz, la-clique, Trojans

Do Not Carry Your Flag Too Low
Actions from Matrix Feminist Design Co-operative

Opening, Monday 7 March 2022, 6 p.m.
Archizoom, SG building, EPFL

Tiago P. Borges, Teresa Cheung, Silvia Groaz, the collectives la-clique and Trojans will inaugurate the Spring semester with an opening lecture of the exhibition Do Not Carry Your Flag Too Low, which they are curating.

The exhibition addresses the subject of inclusiveness of our buildings and common spaces, showing the archive of the radical 1980s feminist architecture practice Matrix. This work explored issues about community and the built environment, and traced the implications of feminist theory and critique on architecture and urban design.

la-clique is an independent platform for exchange and experimentation around architecture at different scales. It questions traditional design methods by cultivating modes of action based on plural intelligence. In resonance with the practices documented in the Matrix archive, the collective explores the act of construction as an integral part of the design process. Standard elements from the world of the construction site, such as fences, tools, pedestals and trellises are reinterpreted, transforming the exhibition space into a space for collective action.

Trojans Collective is a design collective based in Geneva. They have both an experimental and commercial practice based on three axes of work: space, graphic, and multimedia production. Trojans Collective uses design as a tool to critically reflect on contemporary subjects. They work on a process-based method rather than a final goal, they have a strong interest in systems and developing situated projects, mixing their set of skills and backgrounds to push their design further. They are Jessica Maria Nassif, Jeanne Pasquet, Netillo Rojas and Helena Bosch Vidal.

Organized by Archizoom
01/04/2022 @ 12:15 room GC B3 30

CESS Seminar Series - Probabilistic modeling of fatigue resistance for welded joints

Prof. Davide Leonetti, Eindhoven University of Technology

Abstract
The design of civil infrastructures subjected to fatigue loading should satisfy a predetermined safety level, usually expressed in terms of structural reliability. A sound probabilistic model of the fatigue resistance is required for this purpose. A better, i.e. more reliable, modeling of the fatigue resistance allows reducing the uncertainty, especially those related to the threshold, which has economic implications for bridge infrastructures.
This presentation concerns the probabilistic modeling for the fatigue resistance for welded joints in bridges using fatigue resistance curves and based on a fracture mechanics derivation. The fatigue resistance curves relate the load level, i.e. the stress range, to the number of cycles to failure, whereas fracture mechanics enables modeling the macrostructural fatigue damage consisting of the stable cycle-by-cycle propagation of cracks. Two types of cyclic loading are considered: (1) constant amplitude (CA) loading, which is applied in the majority of laboratory tests carried out in the past to characterize the fatigue strength of the material and of structural components and (2) variable amplitude (VA) loading, the type of loading that structural components in bridges experience in service where the threshold phenomena are relevant.

Biography
Davide Leonetti was born on 16-12-1989 in Caserta, Italy. He studied Mechanical Engineering for Design and Production at the “Federico II” University of Naples. In 2015 he graduated within the RaMeG (Railway Mechanics Group) on a thesis about the strength analysis of railway switch maneuvering systems for high-speed railway turnouts for train speeds up to 350km/h.
He got his Ph.D. at Eindhoven University of Technology with a study on the formulation and the use of advanced probabilistic fatigue resistance models for welded joints using both stress-life curves and linear elastic fracture mechanics.
Since 2020 he is employed at Eindhoven University of Technology as an assistant professor in Steel Structures and Structural Health Monitoring. His current research projects concern further investigation of fatigue crack initiation and growth in steel bridges as well as the use of Artificial intelligence for inspection and structural health monitoring of civil infrastructures.

Organized by Prof. Brice Lecampion (GEL) and Prof. Alexandre Alahi (VITA)
28/04/2022 @ 09:00 room MED 0 1418

Smart Publishing

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders' Open Access policy
• Know and protect your rights as an author according to EPFL’s policy
• Get to understand what a publishing contract entails.

Organized by EPFL Library
06/05/2022 @ 12:15 room GC B3 30

CESS Seminar - Structural Health Monitoring of Concrete Infrastructure Employing a Holistic Stress Wave-based Approach

Prof. Thomas Schumacher, Associate Professor in Civil Engineering at Portland State University

Abstract
The goal of structural health monitoring (SHM) is to use sensors and instrumentation to gather quantitative data from a structural system in order to infer on its performance and condition changes, and thus enable an owner to make informed maintenance and repair decisions. To this end, acoustic emission monitoring has been proposed as a passive technique to capture fracture processes within a structure. Recently, active ultrasonic stress wave monitoring has been evaluated, offering high sensitivity to minute and slowly varying changes in a structure such as variations in internal stress and temperature, or development of micro-cracking due to aging and degradation. Both techniques can be performed with the same instrumentation and are fundamentally based on the same physics, which is wave motion in solids. Each technique can provide important insights into processes occurring within a structure. In this seminar, a combined approach that takes advantage of the strengths of both techniques is discussed that offers new opportunities for SHM of concrete infrastructure. A general introduction and the motivation for SHM are discussed first, followed by some select experiments and field tests the presenter has performed over the last 15 years, highlighting the complementary nature of these two techniques. Opportunities for applications and further research conclude the seminar.

Biography
Thomas Schumacher is currently an Invited Professor at the MCS Laboratory at EPFL-ENAC and an Associate Professor in Civil Engineering at Portland State University. After earning his undergraduate degree in Civil Engineering at the Berner Fachhochschule, Switzerland in 2000, he worked as a structural and project engineer for a consulting firm for five years. He left design practice in 2004 to expand his education abroad and earned M.S. and PhD Degrees from Oregon State University in 2006 and 2010, respectively. Schumacher is a licensed professional engineer (PE) in the State of Delaware and an active member of the American Concrete Institute (ACI); he currently serves as the Chair of ACI Committee 444–Structural Health Monitoring. His primary research interests are in the area of non-destructive evaluation (NDE) of civil infrastructure with a focus on concrete structures. In particular, he is interested in stress wave and vibration-based methods such as acoustic emission and ultrasonic monitoring and impulse response testing, respectively. He has also been collaborating with faculty at the University of Delaware to develop a novel distributed carbon nanotube-based sensor that can be integrated with structural composites to form a self-sensing reinforcement to repair and rehabilitate concrete as well as steel structures. Additionally, he is interested in video-based techniques to monitor structural motion. Schumacher’s ultimate goal is to integrate quantitative information from NDE measurements into systems management tools allowing agencies to make informed maintenance and repair decisions.

Organized by Prof. Brice Lecampion (GEL) & Prof. Alexandre Alahi (VITA)
13/05/2022 @ 12:15 room GC B3 30

CESS Seminar - Learned Models for Physical Simulation and Design

Dr Kimberly Stachenfeld, Research Scientist at DeepMind

Abstract

Simulation is important for countless applications in science and engineering, and there has been increasing interest in using machine learning to produce learned simulators to produce simulations more efficiently than classical simulators, distill dynamics into a differentiable model, or learn simulators from real world data. In the first part of our talk, I will describe our recent work on training learned models for efficient turbulence simulation. Turbulent fluid dynamics are chaotic and therefore hard to predict, and classical simulators typically require expertise to produce and take a long time to run. We found that learned CNN-based simulators can learn to efficiently capture diverse types of turbulent dynamics at low resolutions, and that they capture the dynamics of a high-resolution classical solver more accurately than a classical solver run at the same low resolution. We also provide recommendations for producing stable rollouts in learned models, and improving generalization to out-of-distribution states. In the second part of the talk, I will discuss our recent work using learned simulators for inverse design. In this work, we combine Graph Neural Network (GNN) learned simulators [Sanchez-Gonzalez et al 2020, Pfaff et al 2021] with gradient-based optimization in order to optimize designs in a variety of complex physics tasks. These include challenges designing objects in 2D and 3D to direct fluids in complex ways, as well as optimizing the shape of an airfoil. We find that the learned model can support design optimization across 100s of timesteps, and that the learned models can in some cases permit designs that lead to dynamics apparently quite different from the training data.

Biography
Kimberly Stachenfeld is a Research Scientist at DeepMind. Her research focuses on building structured deep learning models of complex systems. She is particularly interested in learned simulation and graph neural networks. She also works on problems in Computational Neuroscience, where she models graph-based learning and reasoning in humans and animals. She received her Ph.D. in Computational Neuroscience from Princeton University in 2018, and her B.A./B.S. in Mathematics/Chemical and Biological Engineering from Tufts University in 2013.

Organized by Prof. Brice Lecampion (GEL) & Prof. Alexandre Alahi (VITA)
13/05/2022 @ 15:00 room

PolyDoc Careers Seminar: Engineering in Film

Christopher Batty, Derek Bradley

The PolyDoc Careers Seminar aims to expose students and postdoctoral researchers to a variety of jobs for which a science or engineering degree is highly valuable. Speakers provide personal perspective about their work, which would not be accessible otherwise, and questions are highly encouraged. The EPFL community at bachelor, master, doctoral, and postdoctoral levels are all equally encouraged to attend.

Zoom link: https://go.epfl.ch/engineeringinfilm

Speaker 1 – Professor Christopher Batty (University of Waterloo, Canada)

Christopher Batty received his PhD in computer science from the University of British Columbia in 2010, and was a Banting Postdoctoral Fellow at Columbia University from 2011-2013. He is now an Associate Professor in the David R. Cheriton School of Computer Science at the University of Waterloo, where he directs the Computational Motion Group. His research is focused on developing physics-based fluid simulation techniques for computer graphics and computational physics applications. He has worked with major visual effects studios and software companies in the film industry, including collaborative research for Side Effects’ Houdini (FLIP fluid solver) and consulting for Weta Digital. Prior to his academic career, he developed physics-based animation software at former Canadian visual effects studio Frantic Films from 2003-2005, and contributed to films such as Scooby-Doo 2, Cursed, and Superman Returns.

https://cs.uwaterloo.ca/~c2batty/

Speaker 2 – Derek Bradley, PhD (DisneyResearch|Studios, Zürich, Switzerland)

Derek Bradley has a PhD in computer science and is now a Director of Research & Development at DisneyResearch|Studios in Zürich, Switzerland, where he leads the Digital Humans research team. He is interested in various problems that involve creating digital humans, including digital scanning, facial performance capture, facial animation, and visual effects for films. His team has been creating high quality digital humans for over a decade, and his work has driven the visual effects in over 30 Hollywood feature films and TV shows, including blockbusters like Avengers, Aladdin, and The Jungle Book. He has over two dozen patents for computer graphics technology that he developed. In 2019, he won a Sci-Tech Oscar for the Medusa Performance Capture System.

http://zurich.disneyresearch.com/derekbradley/

Organized by PolyDoc
03/06/2022 @ 12:15 room GC B3 30

CESS Seminar - Column base connections: Research, design, and a look to the future

Prof. Amit Kanvinde, University of California, Davis

Abstract
Column base connections are arguably the most important connections in steel buildings, transferring loads from the entire structure into the foundation. At the interface of steel and concrete, these connections are complex in terms of behavior, design, as well as structural interactions with the building frame. The lecture will present our current understanding of these connections based on numerous studies, with an emphasis on AISC-funded studies conducted over the last 15 years. Exposed, slab-overtopped, and embedded connections will be discussed, addressing their response (strength, failure modes, stiffness, and deformation characteristics). Implications for design of the connections as well as the building will be presented. Prospective developments in base connection design will be foreshadowed, including a revision of the AISC Design Guide One, and the use of dissipative base connections in seismic design.

Bio
Amit Kanvinde is a professor in the department of civil and environmental engineering at the University of California, Davis. His research is focused on the seismic response of steel structures and connections. He is the recipient of the 2022 T.R. Higgins Lectureship Award from AISC (on the topic of base connections), and has previously received AISC’s Special Achievement Award (2017) and various awards from ASCE, including the Walter Huber Research Prize (2016), the State of the Art of Civil Engineering Award (2018), and the Norman Medal (2008). He is the co-author of the column base plate example (for Steel Moment Frames) in the SEAOC Seismic Design Manual, and is the lead author of the next edition of AISC's Design Guide One on column base connections. His research is cited in numerous standards, and he currently serves on the AISC Connection Prequalification Review Panel, which approves the AISC 358 standard on prequalified moment frame connections.

Organized by Prof. Brice Lecampion (GEL) and Prof. Alexandre Alahi (VITA)
05/06/2022 @ : room

Microcomb 2022 Conference

Microcomb2022 brings together academic and industry leaders across Europe to present latest developments in optical frequency combs and applications of ultra-fast digital signal processing. A poster session is included for PhD and Postdocs.

The conference will take place from June 5 to 9, 2022 in the scenic alpine setting of Saanen, Switzerland at the HUUS Hotel. Registration is open, and please see the conference website: https://microcomb2022.epfl.ch/

Organized by Laboratory of Photonics and Quantum Measurements
01/09/2022 @ 09:00 room Zoom

Smart Publishing

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders' Open Access policy
• Know and protect your rights as an author according to EPFL’s policy
• Get to understand what a publishing contract entails.

Organized by EPFL Library
11/10/2022 @ 11:00 room GC A3 30

CESS Seminar Series - Digital footprints for Mobility Analysis in Public Transport: from Descriptive to Predictive analytics

Dr Latifa Oukhellou, Research Director, Université Gustave Eiffel (France)

Abstract
The last few decades have seen a faster development of digital systems for observing the mobility of people. Various sensing systems such as radio communication, Wi-Fi, Bluetooth, validation of smart cards, mobile phones, and road traffic monitoring systems have enabled researchers and practitioners to acquire large amounts of data, which generally refer to individual and collective trajectories. The mobility data can be further enriched with side information, such as text corpora from social media, survey data, and weather information.
These massive data, temporally and spatially structured, are not necessarily designed to analyze mobility. Still, they can benefit from advanced machine learning and data mining methods, providing decision aid tools and contributing to the development of safer, cleaner, and more efficient transportation systems.
The seminar will be the opportunity to present a synthesis of the research work on smart card data collected on the urban transport network of two cities in France (Rennes and Paris). This presentation will first focus on descriptive methods based on unsupervised learning (clustering), highlighting mobility patterns and transport system usage. The second part will focus on predictive analytics in a supervised learning framework to predict quantities of interest, such as transit network ridership or load passengers in a metro line. The implementation of these methods faces challenges related to the incompleteness, heterogeneity, and strong temporal and spatial correlation within the data, and their high dimensionality or volume.

Biography
Latifa Oukhellou is currently Research Director at Université Gustave Eiffel, France, and the head of the GRETTIA Laboratory (Transportation Engineering and Computer Science Laboratory). Prior to joining Univ Eiffel, she was an Assistant Professor at the University of Paris-Est Créteil. She founded the Data and Mobility Group at the GRETTIA Laboratory in 2011. Her research interests include data mining, machine learning, and information fusion applied to diagnosis problems and to spatio-temporal data mining for identifying driving behavior, analyzing urban mobility or monitoring energy, and water smart grids. She is involved in several research projects in the field of intelligent transportation systems or urban computing for smart cities. She has authored or coauthored over 150 papers in international scientific journals and conference proceedings in the area of data mining, machine learning and transportation science.

Organized by Prof. Alexandre Alahi, Head of VITA lab, EPFL
14/10/2022 @ 17:30 room ELA 1

Spectral properties of extended systems from Koopmans-compliant functionals

Riccardo De Gennaro's PhD public defense.

Thesis director: Nicola Marzari
THEOS - Laboratory of Theory and Simulation of Materials
21/10/2022 @ 12:15 room GC B3 30

CESS seminar series: Damage Identification in Structural Components using Vibrations aided with Physics-informed Neural Networks

Dr Saeid Hedayatrasa, Ghent University (UGent-MMS), Belgium

Abstract
High-performance composite materials have been increasingly used for manufacturing structural components in different industries e.g. aerospace, automotive and wind energy. Given their layered multi-material design, efficient inspection techniques are indispensable for reliable identification of production defects and in-service damage. In this presentation, performance of different techniques in inspection of aircraft composite panels will be compared. Furthermore, detection and quantification of damage through full-field scanning laser Doppler vibrometry and sparse array Guided Wave tomography will be presented. The limitations of the techniques and the potential of Physics-informed Neural Networks for more efficient identification of damage will be discussed and the approach will be examined based on simulation data with added noise.

Biography
Saeid Hedayatrasa is a senior postdoctoral research fellow at the Mechanics of Materials and Structures research group of Ghent University (UGent-MMS) in Belgium. After getting a Master’s degree in Mechanical Engineering and a few years of industrial and post-master research work in Iran, he completed his PhD in Mechanical and Manufacturing Engineering in October 2016 at the University of South Australia. He was employed by the University of South Australia until July 2017 as a research and teaching assistant, after which he joined Ghent University as a postdoctoral researcher. He has computational and experimental background in design optimization and characterization of acoustic meta-materials and composites. More specifically, his research focus has been on analysis of vibrations, elastic wave propagation and heat wave diffusion in advanced materials, and their synergic (vibro-thermal) interaction for non-destructive testing (NDT) and structural health monitoring (SHM). He is currently a visiting researcher at IMOS lab (EPFL) for a research collaboration on developing physics-informed deep learning algorithms for damage quantification through vibrational measurement data.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof . Dusan Licina (HOBEL) and Prof. Alain Nussbaumer (RESSLab)
25/10/2022 @ 12:15 room GC B1 10

EESS talk on "Interplay of biotic and abiotic controls of catchment dynamics"

Dr Sara Bonetti, Tenure Track Assistant professor, Laboratory of Catchment Hydrology and Geomorphology (CHANGE), ALPOLE-Sion

Abstract:
Catchments are natural integrators of a number of ecohydrological and geomorphological processes and providers of key ecosystem services. Yet, in light of the complex interactions of multiple biotic and abiotic processes acting at different spatio-temporal scales, our ability to describe catchment dynamics is still limited. This is particularly evident when climatic and anthropogenic disturbances affect the natural evolution of a landscape. Among the multiple factors shaping the development and functioning of a watershed, vegetation plays a key role in the regulation of water infiltration and overland flow, with repercussions on soil erosional process as well as carbon and nutrient fluxes. Here, I will discuss the role of soil, vegetation attributes, climatic conditions, and their spatial arrangement in shaping ecohydrological fluxes and erosional processes at different scales. I will focus on the contrasting features of natural and intensively managed landscapes to discuss efforts and opportunities in the analysis of anthropogenic disturbances and their impacts on water, carbon, and sediment fluxes. Progress on this front is paramount to foresee the consequences of climate and land use change, devise optimal land management strategies, and avoid critical transitions to unsustainable conditions.

Short biography:
Sara Bonetti joined EPFL in September 2022 as a tenure track assistant professor in Catchment Hydrology and Geomorphology. Before joining EPFL, she was an assistant professor at the Soil Physics and Land Management Group at Wageningen University (the Netherlands). She received a BSc degree in 2009 and a MSc degree in 2011 in Civil Engineering, both from the University of Padova (Italy). From 2012 to 2014 she was a research assistant, first at Duke University (USA) and then at the University of Padova (Italy). In 2018, she obtained her PhD in Civil and Environmental Engineering from Duke University, with a doctoral dissertation on the analysis and modelling of landscape evolution and soil erosion. From August 2018 to July 2020, she was a postdoctoral associate at the Soil and Terrestrial Environmental Physics group at ETH Zurich (Switzerland) and, from March 2020 to September 2021, she worked as a research fellow at the Institute for Sustainable Resources at University College London (UK). Her work focuses on the development of quantitative tools for the description of coupled ecohydrological and geomorphological processes in natural and managed ecosystems.

Organized by EESS - IIE
03/11/2022 @ 12:15 room GC B3 31

CESS seminar: Urban Trajectory Analytics: Emerging Trends and AI-based Applications

Prof. Hwasoo Yeo, Korea Advanced Institute of Science and Technology

Abstract
Recent progress in sensing and data processing techniques has enabled full-scale trajectory data acquisition, which will provide new perspectives to transportation engineers. Urban trajectory analytics provide rich and new information which have not been provided by the traditional sensors, and can deal with diverse problems from microscopic level such as pedestrian-vehicle risk analysis to macroscopic dynamic route choice predictions. This talk will introduce the concept of urban trajectory analytics, data acquisition, data analysis and processing trends and will provide overview on the AI-based applications including urban trajectory prediction and generation, and area-based traffic signal control.

Short Bio
Prof. Hwasoo Yeo was born in Seoul, South Korea, in 1972. He received the B.S. degree in civil engineering from Seoul National University, Seoul, in 1996, and the M.S. and Ph.D. degrees in civil and environmental engineering from the University of California at Berkeley, Berkeley, CA, USA, in 2008. He is currently a Professor with the Department of Civil and Environmental Engineering, KAIST. His current research interests include AI mobility, traffic flow and traffic operations, and intelligent transportation systems.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
08/11/2022 @ 12:00 room MED 0 1418

MechE Colloquium: Flow, transport and mixing limited processes in confined media

Prof. Pietro de Anna, Institute of Earth Sciences (ISTE), University of Lausanne (UNIL)

Abstract: Natural soils are host to a high density and diversity of substances, suspensions and microorganisms, and even deep-earth porous rocks provide a habitat for active microbial communities. In these environments, transport by disordered flows is relevant for a broad range of natural and engineered processes, from biochemical cycling to remineralization, bioremediation and filtration. A key property of most porous systems is the underlying heterogeneity that may occur due to non-uniformity in size or shape of the constitutive grains. Such physical heterogeneity controls transport and mixing of solutes driving geo-chemical kinetics and colloidal/bacterial deposition and filtration. The complexity that rises from the coupling of such microscopic processes makes predictions based on rates measured under homogenized, well-mixed, conditions different by orders of magnitudes from field observations. We use numerical methods and laboratory experiments (based on micro fluidics and time-lapse video-microscopy) to investigate microscopic processes (as flow, mixing, microbial transport and growth) that take place within the confined space of heterogeneously distributed pores. While observing these microscopic processes, we also monitor their macroscopic consequences, including deposition profiles, breakthrough curves, reaction kinetics and biomass growth. Based on such multi-scale observations, we build new theoretical models, that we feed with measured parameters, to unravel the link between microscopic-scale processes and their macroscopic consequences.

Biography: I am physicist, I got a Master from the University of Florence (Italy) in Statistical Mechanics and a PhD in Earth Sciences from the University of Rennes 1 (France), where I studied mixing and reactions in porous media. While I was a postdoctoral fellow at MIT (Boston, U.S.), I learned microfluidics and video-microscopy that I use to develop novel experiments for porous media investigation. Since 2015 I am a professor at the Institute of Earth Sciences (ISTE) of the University of Lausanne (UNIL). I am interested in the physics of flow and mixing-driven processes in confined micro-structures, like filters or soil, with particular attention to their coupling with biological activities. In my group we combine theoretical/numerical approaches to microfluidics experiments to visualize and quantify small scale processes in confined flows in the spirit of modelling their larger scale consequences (upscaling) on reactive transport and filtration phenomena.

Organized by MechE Colloquium
11/11/2022 @ 12:15 room GC B3 30

CESS Seminar - Fracture Mechanics of Faults with Rate-and-State Friction: from slow to fast slip

Prof. Dmitry I. Garagash, Dalhousie University (Halifax, Canada)

Abstract
Numerical simulations show that propagation of slip transients on a fault governed by rate-and-state-dependent friction resembles a fracture whose near tip region is characterized by a large stress departure from the steady-state sliding strength. This observation holds for both slow-aseismic and fast-earthquake-like slip fronts. In this work, we develop a near fracture tip solution that describes the unsteady dynamics and allows to obtain a closed-form expression for the fracture energy $G_c$, associated with overcoming strength-excursion away from the frictional steady-state, as a function of the fracture front speed $v_r$. This allows us to apply the ‘small scale yielding’ concept of fracture mechanics to model rate-state slip transients as singular cracks characterized by the simplified, steady-state frictional resistance in the bulk of the fracture, and by a stress singularity at the fracture tip defined in terms of $G_c(v_r)$ [Garagash, PTRS 2021]. As a result, we develop an analytical equation of motion to study slip driven by a combination of uniform background stress and of a localized disturbance of the fault strength characterized by the net Coulomb force $\Delta T$. The framework can be used to study and forecast run-out of aseismic and seismic slip on faults under either natural (e.g. plate tectonics) or/and anthropogenic (e.g. fluid injection) forcing. For the case of a fluid injection into the subsurface in a fault's proximity, $\Delta T$ becomes a proxy for the injected fluid volume. We show in the case of ongoing fluid injection, that the propagation speed of an aseismic fault slip transient scales with the fluid injection rate. And, once the injection is stopped, the long-term, maximum slip run-out distance on the fault scales with the square of the injected fluid volume. We show that under typical injection scenarios, aseismic slip fronts far outrun the pore pressure diffusion fronts, thus, potentially explaining the triggering of distant seismicity on hydraulically stimulated faults.

Bio
Dr. Dmitry I. Garagash is Professor of Civil and Resource Engineering at Dalhousie University in Halifax, Canada. He received his BS and MSc in Applied Mathematics and Mechanics from Moscow State University and PhD in Geological Engineering from the University of Minnesota. In his research, Dr. Garagash applies mechanics and physics principles to problems in Earth and environmental sciences and geo-energy engineering. He studies hydraulic fracture propagation as pertains to the stimulation of hydrocarbon reservoirs, geological sequestration of liquid waste, and associated fault slip transients and induced seismicity. His other research interests are in the broader physics of the earthquake source, from nucleation to fully developed dynamic rupture, and the underlying constitutive behavior of fault gouge at slow and fast slip.

Organized by Prof. Alex Alahi (VITA), Prof. Olga Fink (IMOS), Prof. Dusan Licina (HOBEL) and Prof. Alain Nussbaumer (RESSLab)
18/11/2022 @ 12:15 room GC B3 30

Rehabilitation of cultural heritage buildings: some contributions and so many open issues

Prof. Daniel V Oliveira, Associate Professor University of Minho, Portugal

Abstract
The conservation and rehabilitation of cultural heritage buildings is a collective social responsibility that is strictly linked to its regular use and promote actively the economic well-being, cultural identity, and quality of life of the population. These tasks pose complex challenges to engineers, but also allow the development of materials, technologies and methodologies towards the suitable safeguard of the built heritage.
The Seminar will show results from recently concluded projects and challenges ahead, ranging from advanced preventive conservation methodologies, seismic protection of earthen constructions based on TRM composites, use of natural fibers for TRM reinforcement, and vernacular constructions.

Bio
Daniel V. Oliveira is currently Associate Professor at the University of Minho. His main research interests are related to the experimental and numerical analysis of traditional and heritage masonry structures, earthquake engineering, repair and strengthening of masonry, earthen construction, vernacular stone heritage, risk analysis, and durability.
Daniel Oliveira has been involved in more than 40 research projects in the field of masonry, funded on a competitive basis. He is the author of more than 300 technical and scientific publications about masonry, holding currently a Scopus h-index of 40. He worked in 5 RILEM committees dealing with the performance of masonry and earthen constructions.
Daniel Oliveira is Deputy Coordinator of the international Master course in Structural Analysis of Monuments and Historical Constructions, coordinated by the University of Minho and funded by the European Commission, award winner of the “EU Prize for Cultural Heritage / Europa Nostra Awards 2017”.
From 2017 to 2019, Daniel Oliveira was the President of the School Council of the School of Engineering, University of Minho, the body in charge of the government and strategic decisions of the School of Engineering.
26/01/2023 @ 13:30 room Online

Smart Publishing

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage? In this workshop, we will address the publication process in the current context:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders' Open Access policy
• Know and protect your rights as an author according to EPFL’s policy
• Get to understand what a publishing contract entails.

Organized by EPFL Library
22/02/2023 @ 12:15 room GC B1 10

CESS seminars: Multiscale Control of Urban Traffic Networks

Prof. Xuegang (Jeff) Ban, University of Washington (USA)

Abstract
Urban traffic system is multiscale in both spatial and temporal domains. Traffic at each scale has its own behavior and dynamics, while interacting with traffic at other scales. In this research, we propose a general multiscale modeling and control framework for urban traffic, motivated by connected and automated vehicles (CAVs). We propose several key concepts for multiscale modeling such as the state consistency between the two scales to establish the stability of the control scheme, as well as a model predictive control (MPC) based solution method. We will share some results of applying the multiscale control method to the Downtown Seattle network, including an MFD-based perimeter control scheme and some thoughts on how it may be integrated into the multiscale framework.

Bio
Dr. Xuegang (Jeff) Ban is the William and Marilyn Conner Endowed Professor with the Department of Civil and Environmental Engineering of the University of Washington. He received his B.S. and M.S. in Automotive Engineering from Tsinghua University, and his M.S. in Computer Sciences and Ph.D. in Civil Engineering (Transportation) from the University of Wisconsin at Madison. His research interests are in Transportation Network System Modeling and Simulation, and Urban Traffic Modeling and Control. His recent work focuses on applying optimization, control, and ML/AI methods to the understanding and modeling of emerging technologies/systems in transportation such as CAVs and New Mobility Services. Dr. Ban is an Associate Editor of Transportation Research Part C, IEEE Transactions on Intelligent Transportation Systems, and Journal of Intelligent Transportation Systems, and serves on the editorial board of Transportation Research Part B. He received the 2011 CAREER Award from the National Science Foundation (NSF), and the New Faculty Award from the Council of University Transportation Centers (CUTC) and the American Road & Transportation Builders Association (ARTBA) in 2012.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
07/03/2023 @ 16:00 room

MechE Colloquium: Haptics, Physical Processes, and Emerging Technologies

Prof. Yon Visell, RE Touch Lab, College of Engineering, Department of Mechanical Engineering, University of California, Santa Barbara (UCSB)

Abstract: I will describe ongoing research from my lab exploring intersecting physical processes, material technologies, and capabilities of both engineered and biological systems. Much of our research concerns human haptic abilities, which are central to human abilities to physically interact with their surroundings. I will describe insights about human haptics that we have derived from empirical and theoretical studies of mechanics. I will also describe recent research projects that exploit physical processes and material attributes in the engineering of technologies, devices, and systems for haptics, sensing, and robotics.

Biography: Yon Visell is Associate Professor at the University of California, Santa Barbara, where he is appointed in the Biological Engineering Program, Department of Mechanical Engineering, Department of Electrical and Computer Engineering (by courtesy), and Media Arts and Technology Program (by courtesy). His academic interests include haptics, soft robotics, emerging material technologies, extended reality, and intelligent systems. He received the Ph.D. in Electrical and Computer Engineering from McGill University, and completed a postdoc at the Institute for Intelligent Systems and Robotics Sorbonne University. His prior degrees are in physics. Prior to his PhD studies, Visell spent several years in industry, including a role developing DSP algorithms for Ableton Live. Through several European organizations, including the experimental studio that he co-founded, he developed technological artworks that exhibited at prominent cultural institutions around the world. Dr. Visell has published more than 85 scientific works. His lab has received a half-dozen awards and many more honorable mentions for work presented at prominent academic conferences. Visell received a Google Faculty Research Award in 2016, a Hellman Family Foundation Faculty Fellowship in 2017, and a US National Science Foundation CAREER award in 2018. Visell served as General Co-Chair of the 2022 and 2024 IEEE Haptics Symposium.

Organized by MechE Colloquium
10/03/2023 @ 12:15 room GC B3 30

CESS seminar - Dynamic rupture behavior and friction evolution revealed by laboratory experiments using ultra high-speed digital image correlation

Prof. Vito Rubino, École Centrale de Nantes

Abstract
Shear cracks along interfaces are relevant to a broad class of engineering and geophysics applications, ranging from the failure of composite materials and bonded joints to earthquakes and landslides. Characterizing the rheology of interfaces and faults is of paramount importance to improve our understanding of frictional ruptures, as friction controls key processes of rupture nucleation, propagation, and arrest and influences various rupture outcomes, for example how damaging earthquakes can be. In this presentation, I will discuss recent advances in the characterization of rupture behavior and friction evolution using our newly developed imaging technique, based on digital image correlation (DIC) coupled with ultrahigh speed photography. One of the highlights of this new approach is its ability to experimentally capture the full-field evolution of particle velocities and strains of spontaneously propagating dynamic ruptures at a level of detail that until recently was possible to achieve only with numerical simulations. Dynamic imaging of stresses enables us to decode the nature of friction by tracking its evolution and studying its dependence on slip, slip velocity and their history. The measured friction behavior allows us to challenge existing friction laws and formulate new ones. This approach gives a new perspective on the study of friction and provides important insights into earthquake and rupture physics.

Short bio
Vito Rubino is Associate Professor at École Centrale de Nantes, France, since September 2022. His research interests focus on experimental and computational mechanics to study fracture and friction phenomena. Dr Rubino received his undergraduate degree from Politecnico di Torino, Italy, while holding a research assistant position at Imperial College London on his final year. He obtained his Ph.D. from the University of Cambridge in 2008. After a brief experience in industry on R&D with Airbus UK, in 2011 he started his postdoctoral studies at the California Institute of Technology (Caltech), in the Department of Aerospace (GALCIT). He then became Research Scientist at Caltech in 2015. He recently earned a NeXT Talent award at Centrale Nantes.

Organized by Prof. Olga Fink (IMOS EPFL), Prof. Alex Elahi (VITA EPFL), Prof. Alain Nussbaumer (RESSLab EPFL) and Prof. Dusan Licina (HOBEL EPFL)
14/03/2023 @ 12:15 room GR A1 402

EESS talk on "Towards educated decision-making on water resources in the face of uncertainty of climate projections"

Prof. Paolo Reggiani, Department of Civil Engineering, University of Siegen

Abstract:
Ongoing global warming requires to periodically revisit and validate adaptation strategies in water resources planning and management to address resource scarcity challenges in the not-to-distant future. This concerns especially the agricultural sector, which in many parts of the world is heavily dependent on freshwater for irrigation, but can be extended to related areas like renewable energy. The main challenge in proposing mitigating actions lies in the uncertainty of climate projections, especially the non-stationarity of the change process. Continuing to assume stationarity or applying simple trend extrapolation to project current states into the future is not to be considered satisfactory and is therefore entrusted to Earth-system model ensembles, which are generated across international model inter-comparison projects (e.g. CMIP5 and CMIP6).
Decision-making in water resources planning can be supported by stochastic optimization approaches, like for instance stochastic-dynamic programming (SDP), which take uncertain temperature, precipitation or surface runoff signals as input to optimize the management of reservoirs or irrigation systems managed through a set operational rules and/or chosen best cropping practices. A sharp and calibrated specification of the uncertainty affecting climate forcing variables through a predictive probability density or approximated via appropriately derived ensembles constitutes the most important prerequisite for reaching optimal decisions. The ensemble spread provided by multiple raw Earth-system model outputs, which is often interpreted as representing true climate uncertainty, requires further processing to obtain a useful predictive density through Bayesian conditioning on observations, under the assumption of weakly stationary processes.
Through an application to rainfall and seasonal temperature over Northern Italy, we show the difference between the probability distributions derived directly from the projection ensembles and those derived after conditioning raw projections on observations. These distributions, directly or in the form of derived ensembles, will be the basis for rationally implementing any further decision-making process.

Short biography:
P. Reggiani holds of the Chair of Water Resources Management and Climate Impact Research at the University of Siegen, Germany. P. Reggiani graduated in Environmental Engineering at the University of Trento, Italy, in 1994. He completed his Ph.D. at the University of Western Australia. Between 1999 and 2000 P. Reggiani worked at CSIRO Land and Water, where he developed modeling approaches to assess dryland salinity in Australia. After his return to Europe in late 2000 he worked as “Marie Curie Fellow” at the soil science lab LTHE in Grenoble, France. In 2002 he took up an appointment as researcher and scientific consultant at the Dutch Institute Deltares. In 2014 he was appointed Full Professor at the University of Sieger. During his career, P. Reggiani worked in various applied scientific and consulting projects in Asia, Africa and Europe. Am important focal point of his scientific work has been the interface between numerical weather prediction and hydrological forecasting, including the area of forecasting uncertainty, as well as operational water management in data-poor areas. P. Reggiani has published more than 50 papers in different areas of hydrology, climate change impacts on water resources, flood forecasting, channel hydraulics and soil science. He also acted as coordinator for several projects, among which the EU FP5 R&D initiative “European Flood Forecasting System (EFFS)”. P. Reggiani partakes in several scientific boards on water resources issues. He is part of the standing Committee on Hydrological Services (Sercom-HYD) at the World Meteorological Organization.

Organized by EESS - IIE
14/03/2023 @ 15:00 room RLC A1 230

monOApoly game session

EPFL Library

As a researcher, do you know how not to get lost in the quest to publish an Open Access article? Discover monOApoly: a new board game about Open Access.

The EPFL Library has developed monOApoly, a new board game which aims to engage researchers with the main concepts of Open Access publishing. Through the use of playful learning, researchers will explore the different ways – the “colors” of Open Access - to achieve the compliance to institutional and funders’ policies. As the game reflects as closely as possible the reality of scientific publishing landscape, players will discover their options to get financial support to publish Open Access (transformative agreements, funders’ support and dedicated library funds), as well as the conditions to deposit articles in their institutional repositories.

Organized by EPFL Library
17/03/2023 @ 12:15 room GC B1 10

CESS seminar series: Fluid effects in frictional faulting

Prof. Nadia Lapusta, Caltech University (USA)

Abstract
The main effect of fluids on frictional faulting is typically expressed through an effective normal stress equal to the fault-normal stress minus the pore fluid pressure. The fault frictional resistance is then given by the product of the effective normal stress and fault friction coefficient. Within this framework, several processes can spontaneously evolve the pore fluid pressure, including thermal pressurization of fluids induced by rapid shear heating, inelastic dilatancy/compaction of the shearing layer, and poroelastic effects that couple pore fluid pressure with bulk deformation. We will focus on two examples illustrating the potential dominance of these effects in earthquake source processes. First, we will show that dynamic weakening due to thermal pressurization may explain the low-heat, low-stress operation of mature continental plate-boundary faults, with the corresponding models reproducing observations of radiated energy and relative paucity of small earthquake events on such faults. Second, we will discuss how the combined effects of poroelasticity and dilatancy significantly affect the response of a fault to fluid injection. Finally, we will show some recent experimental evidence that faults with the same effective stress display different patterns of slip, with stabilizing effects of higher pore fluid pressure. Modeling one of these experiments indicates that the stabilizing effect is not due to dilatancy, for example, but is likely due to changes in friction properties, raising a possibility that the effective stress concept may not be universally applicable. These examples highlight the need to consider fluid effects in modeling fault slip as well as the importance of determining realistic thermo-hydro-mechanical properties of fault zones.

Bio
Nadia Lapusta received her undergraduate degree in Mechanics and Applied Mathematics from Taras Shevchenko National University of Kyiv in Ukraine. She continued her education at Harvard University, receiving her S.M. and Ph.D. degrees in Engineering Sciences in 1996 and 2001, respectively. Since 2002, she has been a faculty at the California Institute of Technology, most recently as Hanson Professor of Mechanical Engineering and Geophysics. She is a co-Director of the NSF I-UCRC Center on Geomechanics and Mitigation of Geohazards (GMG) at Caltech, a co-Leader of the Fault and Rock Mechanics at the Southern California Earthquake Center (SCEC), and an AGU Fellow. Professor Lapusta's interdisciplinary research group works in the areas of computational mechanics of geomaterials, earthquake source processes, fundamentals of friction and fracture, and solid-fluid interactions.

Organized by Prof. Olga Fink (IMOS-EPFL), Prof. Alexandre Elahi (VITA-EPFL), Prof. Dusan Licina (HOBEL-EPFL), Prof. Alain Nussbaumer (RESSLab-EPFL)
30/03/2023 @ 16:15 room MED 2 2423

MEchanics GAthering –MEGA- Seminar: Constrained Efficient Global Optimization of Expensive Black-box Functions

Wenjie Xu (LA3, EPFL)

Abstract:
Optimizing the performance of unknown black-box systems with unmodeled constraints is a ubiquitous problem in science and engineering. In this talk, I will present the CONFIG algorithm, a simple and provably efficient constrained global optimization algorithm to solve it. We also demonstrate the effectiveness of CONFIG algorithm in the applications. It is first applied to a set of artificial numerical benchmark problems to corroborate its effectiveness. It is then applied to a classical constrained steady-state optimization problem of a continuous stirred-tank reactor. Simulation results show that our CONFIG algorithm can achieve performance competitive with the popular CEI algorithm, which has no known optimality guarantee. As such, the CONFIG algorithm offers a new tool, with both a global optimality guarantee and competitive empirical performance, to optimize the performance for a black-box system with soft unmodeled constraints. Last, but not least, the open-source code is available as a python package to facilitate future applications.

Biography:
Wenjie Xu is a Ph.D. candidate in Electrical Engineering with the Automatic Control Laboratory, EPFL, and a guest Ph.D. student with the Urban Energy Systems Laboratory at Empa. He is jointly supervised by Prof. Colin Jones at EPFL and Dr. Bratislav Svetozarevic from Empa. He received MPhil degree from The Chinese University of Hong Kong in 2020 and B.E. degree from Tsinghua University in 2018. His research interests include data-driven optimization, controller tuning, intelligent transportation, and smart energy systems, with research results published in IEEE journals (T-ITS, T-NNLS), ACM conferences (MobiHoc, BuildSys) and control conferences (ACC, IFAC). He received the ASME Energy Systems Technical Committee Best Paper Award at the 2022 American Control Conference.

Organized by MEGA.Seminar Organizing Committee
31/03/2023 @ 12:15 room GC B1 10

CESS seminar - Generating Semantic Building Information Over Time and Space Using Visual Data

Dr Iro Armeni, Postdoctoral Researcher ETH-Zurich

Abstract
Many construction and operation processes, such as those related to sustainable construction and circular economy, require information on the state of the building (spatial), as well as on how it became what it is today (temporal). State-of-the-art approaches attempt to acquire spatial and temporal building information using easily obtainable visual data and Computer Vision algorithms. However most of them examine a static version of our world when for many real-world applications we require a spatiotemporal interpretation of it. The examined change, especially in the 3D domain, is usually constrained to small spatial (e.g., that of a room) and temporal (e.g., that of a few minutes or seconds) scales, and mainly relates to relocation (movement of humans and objects). Considering the lifecycle stages of the built environment, from construction to operation and end-of-use, consisting elements undergo changes that extend beyond relocation and relate to differences in the elements’ geometry, appearance (e.g., floors before and after carpet is added), and topology (e.g., walls begin as a group of studs and gradually change into the final wall structure that users see). To address this, I am employing the challenging setup of construction sites (new or under renovation) as the grounds for developing computer vision methods that are able to work even in the most drastic of changes. The first step is to register 3D point clouds of the same space captured over time since they are almost never aligned in the same coordinate system. In this talk I will present a benchmark and dataset for automatic partial and multi-way registration of the data regardless at which point in time they were captured. This is a very challenging scenario for computer vision algorithms due to the drastic changes in geometry, appearance, and topology that take place over time, as well as the repetitive structure of these scenes. I demonstrate the need for new algorithms that can handle such challenging scenes and drastic changes, as well as the relevance of the dataset.

Short biography
Iro Armeni is a PostDoctoral Researcher at ETH Zurich and an incoming Assistant Professor at Stanford University (Sept. ’23), conducting interdisciplinary research between Architecture, Civil Engineering, and Visual Machine Perception. Her area of focus is on automated semantic and operational understanding of buildings throughout their life cycle using visual data. She completed her PhD at Stanford University on August 2020, Civil and Environmental Engineering Department, with a PhD minor at the Computer Science Department. Prior to enrolling in the PhD program, Iro received an MSc in Computer Science (Ionian University-2013), an MEng in Architecture and Digital Design (University of Tokyo-2011), and a Diploma in Architectural Engineering (National Technical University of Athens-2009). She is the recipient of the ETHZ Postdoctoral Fellowship, the Google PhD Fellowship on Machine Perception, and the Japanese Government (MEXT) scholarship. Iro has worked as an architect and consultant for both the private and public sector.

Organized by Prof. Olga Fink (IMOS), Prof. Alex Elahi (VITA), Prof. Dusan Licina (HOBEL) and Prof. Alain Nussbaumer (RESSLab)
21/04/2023 @ 12:15 room GC B3 30

CESS seminar - Seismic protection in subduction environments

Prof. Juan Carlos de la Llera, Pontificia Universidad Catolica de Chile (PUC)

Abstract
Seismic protection is already a mature field in earthquake engineering. Despite their already proved great benefits in reducing the building response, the different technologies have not achieved a level of penetration in construction practice consistent with these benefits. Indeed, the different technologies are still seen by some people in the profession with skepticism, and are sometimes resisted by investors in practice. However, very active subduction environments like the one in the Pacific margin of Chile, are particularly adequate for the use of such technologies, given the large magnitude, frequency, and duration of the ground motions generated over very vast regions of the country. This talk will summarize the innovation trajectory we have traveled in developing and introducing different seismic protection technologies in Chile and elsewhere, and discusses some of the most significant challenges and shortcomings we have encountered in this process. We will touch upon some relevant research gaps in this field, but also the gaps observed in current practice in the country and seismic codes, which may also carry over to other places in the world. It will also introduce some newer ideas in seismic isolation and energy dissipation techniques, keeping in mind a general audience, not only specialists in the field. Toward the end of the presentation, research ideas for the integration of seismic protection in networks under the framework of earthquake risk and resilience evaluation will be presented. The audience will get a reasonably good understanding of the status of seismic protection in Chile, the basic mechanics of the implemented systems, some basic knowledge on the characteristics of subduction ground motions, and the types of challenges I foresee in the future in the field of seismic protection.

Short biography
Juan Carlos de la Llera is currently a visiting professor during the spring semester at EESD, EPFL. He is a professor in Civil Engineering at Pontificia Universidad Catolica de Chile (PUC) since 1995, M.Sc., and Ph.D. from UC Berkeley (’94). He is also the former 12-year dean of the Faculty of Engineering at PUC, and has a long trajectory as a researcher in the fields of nonlinear structural dynamics, earthquake performance, seismic protection, and earthquake risk and resilience analysis. He has been the founder of several companies that belong to the university, two of them in seismic protection, and over the years have supported many technology-based entrepreneurial activities in the country. He led the national strategy for National Disaster Resilience (2016) that led to the national Public Technological Institute in Resilience, Itrend. His trajectory shows many research and professional awards, and recently his work as an innovative dean in engineering has also been recognized with the highest honors by the Instituto de Ingenieros and the Colegio de Ingenieros. Currently, he is also a member of the Chilean and Pan-American Academy of Engineering.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL) and Prof. Alain Nussbaumer (RESSLab)
28/04/2023 @ 12:15 room GC B3 30

CESS seminar series - Technological Challenges for Deep-Water Steel Pipeline Construction

Prof. Spyros A. Karamanos, University of Thessaly, Volos (Greece)

Abstract
The construction of steel hydrocarbon pipelines in deep sea is a technological challenge. Recent scientific and engineering advancements allow for the design and installation of pipelines at depths that exceed 2,000 meters. The present lecture is motivated by the recent developments on natural gas exploitation and production in East Mediterranean. In that region, major gas pipelines are designed for installation in water depths that reach 3,000 meters, to transmit the produced natural gas to the European market.

The first part of the lecture presents the basic parameters of offshore pipeline structural design and the corresponding limit states from a holistic point-of-view, from line pipe production at the pipe mill to the installation process in deep water. The second part of the lecture summarizes recent state-of-the-art research at the University of Thessaly on two topics related to the structural integrity of offshore pipelines, namely: (a) the effect of line pipe manufacturing process on the collapse strength of deep offshore pipelines, and (b) the structural performance of bi-material pipes (also called “lined pipes”), a rather new, very efficient solution for mitigating internal corrosion of the pipeline.

Short bio
Spyros A. Karamanos is Professor of Computational Structural Mechanics in Mechanical Engineering, at the University of Thessaly, Volos, Greece. During 2016-2019, he was Professor and Chair of Structural Engineering, The University of Edinburgh, Scotland, UK, in parallel to his professorship in Greece.
He received his five-year Diploma in Civil Engineering from the National Technical University of Athens, Greece, in 1989 with highest honors, and his M.Sc. (1991) and Ph.D. (1993) degrees in Structural Engineering & Mechanics, from The University of Texas at Austin, USA.
His research and professional interests include Structural Mechanics, Numerical Methods and Finite Elements, Structural Stability, Inelastic Behavior, Analysis and Design of Metal Structures against Fatigue, Earthquake Engineering and Structural Dynamics. He specializes in structural mechanics and integrity of energy infrastructure systems, focusing on buckling and fatigue of pipelines and offshore structures, mainly tubular components and systems, using computational and experimental methods. His research has been funded primarily by European research projects, with the participation of European steel and pipeline industry, also directly by industrial partners. He has published more than 85 papers in refereed journals and more than 170 papers in conference proceedings.

Organized by Prof. Olga Fink (IMOS-EPFL), Prof. Alexandre Elahi (VITA-EPFL), Prof. Dusan Licina (HOBEL-EPFL) and Prof. Alain Nussbaumer (RESSLab-EPFL)
05/05/2023 @ 12:15 room GC B3 30

CESS seminar series - Advanced Testing and Digital Twinning of Large-scale Thin-walled Composite Structures

Prof. Xiao Chen, Technical University of Denmark

Abstract
With a length of over 120 m, composite wind turbine blades are among the largest single components in the world which are primarily made of fiber polymer composite materials. Working in harsh environments and under complex loading, such large-scale, thin-walled composite structures must maintain their structural integrity and reliability over 25 years service life with minimum maintenance. This challenges the wind energy industry in many ways as the time to market is crucial and yet the prototype certification is extremely expensive and time-consuming. In this seminar, the latest research and innovation in advanced structural testing and high-performance modeling techniques of large-scale thin-walled composite blade structures will be presented. Particular focus will be placed on full-scale and subcomponent structural testing under realistic static and fatigue loads, novel computer-vision-based damage inspection and structural health monitoring techniques, and advanced finite element modeling techniques that can predict complex fracture and damage phenomena in full-scale wind turbine blade structures and their critical structural details – not only accurately but also efficiently. The simulation efficiency and calculation speed are greatly escalated to an unparalleled level by several recently developed key enabling technologies which will achieve high-fidelity and high-speed digital twinning of such large-scale thin-walled composite structures.

Short bio
Dr. Chen is Associate Professor at Department of Wind and Energy Systems at Technical University of Denmark (DTU). He received his doctoral degree in structural engineering in 2011 from Nagoya University in Japan and worked as a postdoctoral research fellow in the National Wind Energy Center at the University of Houston, Texas, USA. From 2013, he was an assistant professor and then associate professor at the Chinese Academy of Sciences in Beijing before he joined DTU in 2017, where he is the team leader of composite structures. Dr. Chen is a member of several international scientific and technical committees such as the International Ship and Offshore Structures Congress, Villum Center for Advanced Structural and Material Testing, International Conference on Composite Structures, and International Conference on Mechanics of Composites. He is the Principe Investigator of several research projects funded by Innovation Fond of Denmark, the Danish Energy Agency, the European Commission, The Villum Foundation, Danish Energy Technology Development and Demonstration Program and the National Science Foundation of China. He has published more than 30 research articles in the field of advanced testing and high-performance modeling of composite blades with a focus on structural damage, fracture and digitalization using Industry 4.0 technologies.

Organized by Prof. Olga Fink (IMOS-EPFL), Prof. Alexandre Elahi (VITA-EPFL), Prof. Dusan Licina (HOBEL-EPFL) and Prof. Alain Nussbaumer (RESSLab-EPFL)
08/05/2023 @ 12:00 room SV 1717

Discover OMERO

Céline Gagnieux, Constam Lab -
Tanes Imamura de Lima, Auwerx Lab -
Nicolas Chiaruttini, BIOP

Store your imaging data in a secure reproducible manner using the EPFL OMERO server.
Discover functionality and see use cases from early adopters.

Organized by Romain Guiet, BIOP
Rémy Dornier, BIOP
Arne Seitz, BIOP
12/05/2023 @ 12:15 room GC B3 30

CESS Seminar : Damage signatures and imaging of crustal fault zones

Prof. Tom Mitchell, UCL

Abstract
Crustal fault zones (FZ) have been studied by field geologists, seismologists and experimentalists for decades, and are mapped directly at the surface, and inferred from geophysics at depth. In a FZ, fault slip is commonly hosted in a narrow fault core, surrounded by a fracture damage zone of variable size up to 100s of metres in width. This damage is accrued by a combination of quasistatic and coesismic processes. With increasing displacement and fault maturity, FZs increase both size and complexity, due to overprinting of incremental damage. Fracture damage in FZs imparts a fundamental control on earthquakes.
Firstly, FZs rocks are generally more permeable than intact rocks, and hence play a key role in the migration of crustal fluids. Damaged rocks have reduced elastic moduli, cohesion and yield strength resulting in reduced elastic wave velocity, causing attenuation and potentially non-linear wave propagation effects during ruptures. The amount and spatial variation of these reductions can directly modify rupture dynamics, leading to the generation of slip pulses that can accelerate the transition to supershear rupture. Significant reductions of velocity within a FZ results in the structures trapping seismic waves that can continuously perturb stresses on the fault during earthquakes. At the same time, these low velocity zones can be used to infer damage structure at depth. Finally, the dynamic generation of damage as the rupture propagates can itself influence the dynamics of rupture propagation; by increasing energy dissipation, modulating the rupture velocity and modifying the size of the earthquake, changing the efficiency of weakening mechanisms such as thermal pressurisation of pore fluids, and even generating additional seismic waves. All of these effects imply that a feedback exists between the damage imparted immediately after rupture propagation, at the early stages of fault slip, and the effects of that damage on subsequent ruptures dynamics.
To complicate matters, with increased pressure and temperature at depth, the structure, mechanical, and hydraulic characteristics of a FZ are subject to constant change (e.g. healing and/or sealing) during the seismic cycle as the fault evolves. This can complicate interpreting geophysical data when some damage can heal rapidly, and be subsequently invisible to many geophysical techniques. Additionally, the structure and physical properties of damage depends not only on fault maturity, but also on the scale of observation and the types of techniques used to map and infer fault structure at depth. As techniques and technology improve, we are quantifying FZ structure and damage in the field and laboratory from the kilometre to metre scale, down to the nano-scale, and combining this with advances in seismic event location and high resolution tomography we have increasingly better ideas of how these structures evolve with depth. This presentation addresses the state-of-the-art of our understanding of FZ structure, and reflects on how we image and interpret fault structures at the surface and below.

Short bio
Tom Mitchell is a professor of earthquake geology and rock physics. He did his phd in Liverpool, postdoc fellowship in Japan/Hiroshima, Bochum/Germany, INGV/Rome, and been at UCL for the last 9 years. He uses a combination of laboratory, fieldwork and theoretical approaches in order to understand how rock and ice fractures, deforms and slides by friction. He works on a range of topics studying the deformation of geomaterials, from earthquakes/fault damage, fault friction, fluid flow/ geothermal, landslide mechanics (earth, moon and mars), ice fracture and a variety of other applied areas.

Sandwiches are offered at the end of the seminar

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL) and Prof. Alain Nussbaumer (RESSLab)
19/05/2023 @ 11:00 room HBL 0 21A

First joint Smart Living Lab and IIC seminar : Exposing the Brain: The cognitive impacts of indoor air pollution

Prof. Jeffrey Siegel, University of Toronto Canada

Abstract
Poor indoor air is often our largest environmental health risk, yet known chronic health consequences accumulate over a lifetime of exposure in different buildings, limiting public interest, investment, and regulatory action. Even with current increased focus on indoor air quality because of the pandemic, it is likely that the attention will diminish over time, as it has with other indoor hazards. However, exposures to indoor contaminants also negatively influence cognitive function and high-level decision making. These influences, although currently poorly understood, offer a sustained model for indoor air improvement with the costs for such improvements covered by the economic benefits from cognitive function improvements in environments such as schools and office buildings. This presentation discusses the current state of research on cognitive function impacts including research on carbon dioxide, volatile organic compounds, and emissions from essential oil diffusers with a particular focus on understanding the fundamental connections between indoor exposures and neurocognitive processes

Short bio
Jeffrey Siegel, Ph.D., is Professor of Civil and Mineral Engineering at the University of Toronto and is a Bahen/Tanenbaum Chair in Civil Engineering. He holds joint appointments at the Dalla Lana School of Public Health and the Department of Physical & Environmental Sciences. He has an M.S. and Ph.D. in Mechanical Engineering from the University of California, Berkeley as well as a B.Sc. from Swarthmore College. He is internationally recognized for his work on indoor air quality generally and air cleaning specifically and is a fellow of ASHRAE and a member of the Academy of Fellows of the International Society for Indoor Air and Climate (ISIAQ). His research interests include healthy and sustainable buildings, filtration and air cleaning, ventilation and indoor air quality in residential and commercial buildings, control of indoor particulate matter, and the impact of building systems on indoor microbiology and chemistry. He has published over 100 peer-reviewed journal articles on indoor air quality and related subjects and has been active in disseminating information about filtration and ventilation solutions for COVID-19.

Sandwiches offered at the end of the seminar.

Zoom link provided on demand at adeline.guelat@epfl.ch

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLAB)
22/05/2023 @ 14:00 room BC 420

EPFL shapes Open Science | Open Access: Which Way Forward?
The Open Science office launches the first event of its new series "EPFL Shapes Open Science":

Open Access: Which Way Forward?

An interactive event to address the current issues in Open Access academic publishing and rethink together the way we share our work to the world, organized in collaboration with the EPFL library.

Registration here

*********************************
Open access to knowledge should be the norm, and this starts with publications. Implementing this has proven difficult though, due to several factors.
At the moment, in research, the key to success lies in which journal one publishes in. Journal names have become a replacement for the quality of our work, leading us to prioritize their reputation over their commitment to open access.

Can we trust the content of an article because it's published in a prestigious journal though? And if we genuinely value sharing the knowledge we produce, should we leave it to external entities to control its dissemination? Who exactly owns our publications, and how much does this entire system cost us?

Come to this event to find out, join the discussion and share your voice!

Program:
- Introduction by VPA Jan Hesthaven.
- Short documentary explaining the current state of Open Access in Switzerland and exposing three scenarios for the future.
- Vote from the audience for one of the three Open Access Scenarios.
- Roundtable discussion tackling these three possible ways forward and what they entail for researchers, moderated by Mirko Bischofberger and starring:
  - Katrin Beyer, ENAC Professor and Associate Dean for Digitalization and Open Science
  - Bob West, IC Professor
  - Abdullah Talayhan, IC PhD student
  - Gilles Dubochet, Head of Open Science
  - Claudio Aspesi, External Consultant and Expert Analyst in academic publishing
- Second round of votes from the audience.
- Conclusive remarks by VPA Jan Hesthaven.
Organized by VPA- Open Science
13/06/2023 @ 14:00 room CO 015

Workshop on Copyright & Second Publication Right

CCdigitallaw (Competence Center in Digital Law)
Within the project Regulatory Framework financed by swissuniversities, CCdigitallaw (Competence Center in Digital Law) is proposing a workshop on the topic of Copyright & Second Publication Right.

The workshop is addressed to all researchers in Switzerland who are curious to learn more about the possibilities of the second publications (the green road of Open Access).

The workshop will cover the following topics:
- When is a work protected by copyright and for how long?
- Who is the author and who the right holder?
- What are Creative Commons Licenses?
- What is the role of the 5 Swiss Collecting Societies?
- Open Access and Second Publication Right: what is currently possible and in what directions are current discussions going?
This workshop is hold in English, free of charge and followed by an aperitif!

Registration

This workshop is organized on EPFL campus with the support of EPFL Library. Find more information about the other workshops organized by CCdigitallaw in Switzerland.
Organized by EPFL Library
07/07/2023 @ 11:00 room Room GC B1 10

CESS Seminar : Magma propagation by diking: geophysical observations and mechanical models of the pathways followed by fluid-filled cracks

Prof Eleonora Rivalta (University of Bologna)

Abstract
Magma propagates in brittle elastic rocks by diking, which is a form of hydraulic fracturing. Dikes are voluminous (>10^5 m^3) magma-filled cracks oriented roughly perpendicular to the least compressive elastic stress axis, driven by their buoyancy pressure or by external stress gradients such as those induced by the flanks of a volcano. Prof Eleonora Rivalta will illustrate high-quality geophysical observations of recent dikes, focusing on deformation and seismicity. Next, she will illustrate the models her students and herself have developed over the years, first in 2D and, more recently, in 3D, as well as their strategy to forecast future magma pathways and the opening location of future eruptive fissures.

Short Bio
Eleonora Rivalta is a senior scientist at the German Research Centre for Geosciences in Potsdam and an Associate Professor at the University of Bologna in Italy. She graduated from the University of Bologna (both a Master's and PhD in Physics). She did post-docs at the University of Hamburg and in Bologna and spent a long research stay in Stanford with Paul Segall. Next, she worked as a lecturer at the University of Leeds, UK. Finally, she moved back to Germany where she started her ERC Starting Grant group on the physics of magma propagation. Her main interests are the mechanics of magma propagation by diking, especially modelling the influence of crustal heterogeneities and the external stress field on the expected magma trajectories, and simulating the expected geophysical observations.

Sandwiches will be provided at the end of the seminar

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
16/07/2023 @ 12:00 room BC 01

Switzerland's Image and Data Analysis School (ZIDAS) 2023

an amazing group of instructors (locally sourced through SwissBIAS, and across europe)

We are happy to repeat the success of last year's ZIDAS and open the doors of the Ecole Polytechnique Fédérale de Lausanne to a fresh new batch of candidates.

25 candidates will join our amazing group of instructors (locally sourced through SwissBIAS, and across europe), and tool developers in order to work on their own data for 5 days.

Hands-on sessions will be dedicated to well established open source tools with an emphasis on macro language coding for creating reproducible workflows

Programming knowledge is not required, but an eagerness to learn is welcome! What is important is your biological question and a motivating cover letter to get your application noticed.

Important dates:
Course runs from July 16th (Yes, Sunday) to July 21st 2023.
Registration is open until 2022-04-01. You will be informed of your participation on 2022-04-17

Organized by EPFL
ETHZ
FMI
UniBasel
19/09/2023 @ 11:00 room HBL0 21A

Joint Smart Living Lab and IIC seminar : The effect of air quality on sleep and cognitive performances

Assoc. Prof. Pawel Wargocki (DTU)

Abstract
High indoor air quality and comfortable temperatures are prerequisites for good work, learning and undisturbed sleep

The Civil Engineering Institute and the Human-Oriented Built Environment Lab (HOBEL) of EPFL ENAC invite Pawel Wargocki, Associate Professor at the Technical University of Denmark (DTU) to introduce his research on Indoor Air Quality.

In the last 25 years, numerous research studies have documented the importance of improved air quality and comfortable temperatures on work performance and learning. Studies have been carried out both in the laboratories and in actual buildings, in different climates and regions of the world. They are consistent and document small but relevant effects on cognitive performance. Subsequent economic calculations show that even a few percent change in performance will be justified in terms of investments to improve the conditions indoors.

Last 10 years have additionally documented the effects of thermal conditions and indoor air quality on sleep with the potential consequences for the next day performance. The picture is clear – maintain good conditions indoors is a prerequisite for high life quality and should not be compromised. The challenge is to develop the solutions that on the one hand improve conditions indoors and on the other have no impact on CO2 emission. Present lecture will summarize the evidence and discuss the future challenges concerning the achievement of high indoor environmental quality.

Short bio
Assoc. Prof. Pawel Wargocki (54) graduated from the Warsaw University of Technology in 1990. He received his Ph.D. from the Technical University of Denmark in 1998, where he has been teaching and performing research ever since. He has >25 years of experience in research on human requirements in indoor environments. He is best known for his seminal work, demonstrating that poor indoor environmental quality affects office work and learning performance. Other work influenced the requirements for ventilation and air cleaning. Recent research includes studies on emissions from humans, sleep quality, and performance of green buildings and gas-phase air cleaning and air quality in aircraft.

He has collaborated with leading research institutions, universities, and industrial partners worldwide, including the National University of Singapore, Jiaotong University in Shanghai, Syracuse Center of Excellence, United Technologies, Velux, and Google. He stayed as a guest professor at Pufendorf Institute at Lund University, Waseda University, and the National University of Singapore. He was President and long-standing board member of the International Society of Indoor Air Quality and Climate (ISIAQ), Vice President of Indoor Air 2008, and Chair of ASHRAE committees. He was a President of the Academy of Indoor Air Sciences. He has received several awards for his work, including the Rockwool Award for Young Researchers, ASHRAE Ralph Nevins Award, Environmental Health Award, Distinguished Service Award, ISIAQ’s Yaglou Award, and Best Paper Awards in Indoor Air. He published extensively.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
22/09/2023 @ 10:00 room SV 2715

Open Access Q&A session

EPFL Library Publishing Support team

Do you want to know more about the Open Access alternatives you have when publishing your article?
Are you interested in exploring the Gold Open Access financial support options available for EPFL authors?

The EPFL Library Publishing Support team will be available for the SV community to answer all your questions.
Free, and without registration entrance.

Anyone who would like to know more about Open Access is welcome at the SV building, room SV 2715.
Come at your convenience between 10.00 and 11.00.

A second session is scheduled on October 10^th, between 10.00 and 11.00.

Organized by EPFL Library
06/10/2023 @ 12:15 room GC B1 10

CESS Seminar : From Concept to Completion : The Journey of Carbon Fiber Reinforced Polymers in Bridge Construction

Prof. Urs Meier (EMPA)

Abstract
In the early 1980s, a small group of researchers began exploring the potential of fiber-reinforced polymers (FRP) for use in bridge construction. Most of them focused on glass, some on aramid, and few, like at Empa, on carbon fibers. In Switzerland, KWF, now known as Innosuisse, supported two Empa projects: the development of parallel wire tendons made of unidirectional carbon fiber reinforced polymers (CFRP), and a post-strengthening concept for steel reinforced concrete bridges using thin unidirectional CFRP strips. However, significant obstacles arose, such as the transfer of high longitudinal stresses into anchorage systems and concrete structures.

Nevertheless, full-scale CFRP pilot applications in bridge construction succeeded in the 1990s. The CFRP post-strengthening technique quickly became a state-of-the-art solution worldwide and a commercial success. CFRP tendons as stay or post-tensioning cables in early sponsored projects proved to be very reliable and technically successful. Nevertheless, there were no follow-up projects. Despite the successes of the pilot projects, building authorities were slow to acknowledge the outstanding properties of CFRP tendons, including corrosion resistance, outstanding fatigue properties, and lightweight for tendons.
In 2021, a large network arch railway bridge near Stuttgart, with all hangers made of CFRP tendons, broke the ice. Researchers and engineers demonstrated that the CFRP solution is not only more economic but also much more sustainable. Further large bridges of this type are already under construction. New visions continue to emerge, such as the possibility of producing structural CFRP components from CO₂ captured from the air. Ultimately, the progress and continued development of CFRP technology are paving the way for a more sustainable and efficient future in bridge construction.

Short bio
Urs Meier has held various positions at the Swiss Federal Laboratories for Materials Science and Technology (Empa). In 1989, he was promoted to the rank of Managing Director of Empa in Dübendorf, a position that he held until his retirement. Additionally, he has been a professor at the Swiss Federal Institute of Technology (ETH) in Zurich. Throughout his career, he has made significant contributions to the application of carbon-fiber-reinforced polymers (CFRP) in civil engineering, earning worldwide recognition for his pioneering research. Notably, his work on post-strengthening civil structures with CFRP laminates and the application of CFRP stay-and post-tensioning cables has had a significant impact on the field. Currently, he serves as a technology consultant for the application of CFRP in bridge construction at Empa.

Sandwiches offered after the seminar

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
06/10/2023 @ 13:30 room GC B1 10

CESS Seminar : Frictional sliding : The effect of interfacial heterogeneities

Dr. Elsa Bayart, ENS Lyon

Abstract:
What happens at the interface between two solid bodies in contact when they start sliding? This problem has important implications to various fields such as engineering, where the challenge is to control friction, or earthquake dynamics, where prediction of earthquakes occurrence and magnitude is crucial.

A frictional interface is composed of an ensemble of discrete contacts that resist to shear. Sliding motion is mediated by the propagation of an interfacial rupture, breaking the micro-contacts, that has been shown to be a true shear crack. Through laboratory experiments, we study how interfacial disorder affects the onset of sliding of two solid bodies in contact. We show that disorder can drastically modify the macroscopic dynamics of the interface via the modification of the fracture initiation or propagation processes. The impact of our results on earthquakes dynamics will be discussed.

Short bio
Dr. Elsa Bayart received her M.S. in Physics from the University of Paris 6, and her Ph.D. from the Ecole Normale Supérieure, Paris, with Prof. Mokhtar Adda-Bedia and Prof. Arezki Boudaoud, where she focused on the description of geometrically frustrated elastic systems using tools from statistical physics. After receiving a postdoctoral fellowship from the Lady Davis Trust, she conducted research at the Hebrew University of Jerusalem under the supervision of Prof. Jay Fineberg on the onset of frictional sliding, based on original experiments allowing the tracking and characterization of interfacial fractures. Since 2017, she is a CNRS researcher and a member of the Physics Laboratory of ENS Lyon (France). She conducts research in solid mechanics related to geophysical challenges. She is particularly interested in the dynamics of frictional systems, with the aim of studying the mechanics of seismic faults in the laboratory, as well as the mechanical behavior of granular suspensions under large deformation.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
10/10/2023 @ 10:00 room SV 2615

Open Access Q&A session

EPFL Library Publishing Support team

Do you want to know more about the Open Access alternatives you have when publishing your article?
Are you interested in exploring the Gold Open Access financial support options available for EPFL authors?

The EPFL Library Publishing Support team will be available for the SV community to answer all your questions.
Free, and without registration entrance.

Anyone who would like to know more about Open Access is welcome at the SV building, room SV 2615.
Come at your convenience between 10.00 and 11.00.

Organized by EPFL Library
12/10/2023 @ 11:00 room GC B3 31

CESS Seminar : Context-Aware Assortment Optimization in Platform-Based Urban Mobility - Prof. Maknoon and Tactical planning for dynamic transportation problems - Prof. Pisinger

Prof. Yousef Maknoon (TU Delft) and Prof. David Pisinger (DTU)

Abstracts
Context-Aware Assortment Optimization in Platform-Based Urban Mobility - Prof. Yousef Maknoon
This study delves into the role of context effects in assortment optimization for platform-based urban mobility services, challenging the assumptions of classical Random Utility Maximization (RUM) models. We employ the Random Regret Minimization (RRM) model and introduce a novel 'Marginal Decoy Policy' specifically designed to capture behavioral anomalies arising from context effects. Through comparative analyses with established models such as Multinomial Logit (MNL) and Generalized Random Regret Minimization (G-RRM), we demonstrate the efficacy of our approach. The findings elucidate new strategies for dynamic service menu optimization, significantly enhancing customer satisfaction and retention by taking context effects into account.

Tactical planning for dynamic transportation problems - Prof. David Pisinger (DTU)
We consider the tactical planning aspect of a dynamic transportation problem with a time horizon of several days. Some tasks are known beforehand, while others arrive dynamically. The tactical planning is to schedule the known tasks, such that we minimize the overall driving distance while ensuring short service times for the dynamic tasks.

Without tactical planning, the known tasks would be spread throughout the whole area as they are scheduled based on a first-come-first-serve principle. In this study, we partition the area into disjoint slices covering the full plane and then assign the slicesto individual work days. Computational results are reported showing around a 10% reduction in driving distance when using tactical planning, while still being resilient to the dynamic tasks. Furthermore, we show that up to 70% of the drivers can have a non-changing work day, without a significant increase in driving distance.

Short bios
Prof. Yousef Maknoon is a faculty member at the Faculty of Technology, Policy, and Management (TPM) at TU Delft. He is also the director of Orbit Lab, a research group specializing in Operations Research and Behavioral Informatics in Transportation. His research takes a multidisciplinary approach, firmly rooted in operations research, to tackle emerging challenges in the transport and logistics domain. In recent years, his primary focus has been on the design and operational strategies for on-demand and instant logistics services, driving the evolution of this dynamic field.

Prof. David Pisinger, is professor in operations research at Technical University of Denmark (DTU). His research interests include Maritime optimization, Vehicle Routing, Railway optimization, Energy models, and Wind Farm Layout. He has been leading several research projects in maritime logistics, railway optimization, and packing and loading. David received the Hedorfs Fonds prize for Transport Research 2013, the Glower-Klingman Prize 2019, and he was one of the finalists for the Franz Edelman Prize 2019. Over the years he has supervised more than 30 PhD students. Many of these have received international awards, like the VeRoLog dissertation prize, TSL dissertation prize, EURO doctoral disseration award. Having a background in Knapsack Problems, David Pisinger can be recognized by the fact that he always carries a backpack.

Sandwiches offered after the seminar

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
27/10/2023 @ 12:15 room GC B1 10

CESS Seminar : A phase-field model for fracture and its applications in geoscience

Prof. Keita Yoshioka - Montanuniversität Leoben

Abstract:
Fracturing is applied to stimulate wells in hydrocarbon and geothermal energy production. In well stimulation operations, fractures are deliberately created, but they are something to avoid or to be controlled in underground energy and CO2 storage or nuclear waste disposal. This shift in the focus prompts us to study not only propagation but also nucleation of fractures. And subsequently we need simulation capabilities for both propagation and nucleation.

In this presentation, Pr. Keita Yoshioka will briefly go over a phase-field model, which has witnessed contagious popularity originated from the mechanics community to the geo-community. Part of this success is because of its ability to capture complex fracture behaviors, including nucleation and propagation along complex unknown path in 2 and 3 dimensions without the need for ad-hoc criteria and geometric restrictions on crack path. He will then focus on its applications and necessary adaptations for hydraulic fracturing with some comparative examples. Finally, he will close his talk with some application examples in complex hydraulic fracturing.

Short bio
Dr. Yoshioka received his Bachelor of Science in Resources and Environmental Engineering from Waseda University, Japan in 2003 and PhD in Petroleum Engineering from Texas A&M University in 2007.

He then joined Chevron's geomechanics teams in Houston. He conducted internal consulting and corporate researches on various geomechanical problems for more than 10 years including a short term assignment in Chevron's geothermal operation in Indonesia.

In 2017, he moved to Germany and started working on an open source code development project at the Helmholtz Centre for Environmental Research focusing on computational fracture mechanics.

Since 2022, he has been professor for geo-energy production engineering at Montanuniversität Leoben.

Sandwiches offered after the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
31/10/2023 @ 11:00 room BC 04

The role of Instruction-tuned Models as Annotators: Exploring Label Variation

Flor Miriam Plaza-del-Arco is a Postdoctoral Research Fellow at the MilaNLP group at Bocconi University (Italy).
Her research interests mainly focus on Natural Language Processing, particularly in hate speech detection, emotion analysis, early web risk prediction, and large language models evaluation.

The zero-shot learning capabilities of large language models (LLMs) make them ideal for text classification without annotation or supervised training.

any studies have shown impressive results across multiple tasks. While tasks, data, and results differ widely, their similarities to human annotation can aid us in tackling new tasks with minimal expenses. The ultimate promise of LLMs is that their language capability lets them generalize to any text classification task. What if the answer is not to wait for one model to rule them all, but to treat their variation similar to the disagreement among human annotators? Not as individual flaws, but as specializations we can exploit.

In this talk, we will explore the potential of state-of-the-art instruction-tuned models to serve as "annotators" across various established NLP tasks, including sentiment classification, age and gender prediction, topic classification, and hate speech detection. We will answer two fundamental questions: Do we continue to require human annotators, and do the variations in human labeling also manifest in LLMs? Additionally, we will discuss the tradeoffs between speed, accuracy, cost, and bias when it comes to aggregated model labeling versus human annotation

Organized by Antoine Bosselut, Natural Language Processing (NLP) lab, EPFL.
03/11/2023 @ 12:15 room CM 1 106

Hydrological innovation for the climate emergency

Prof. Lindsay Beevers

Abstract:
Natural hazards such as floods and droughts are set to intensify in the future as a direct result of the climate emergency - in terms of magnitude as well as frequency. These changes play out against a backdrop of increasing global urbanisation and as such poses challenges to the way we live in and manage our cities in the future. Alongside the race to net zero and climate mitigation – we need to adapt to the changing climate and increase our resilience. For this we need hydrological innovations in order to characterise and quantify hazards – now and in the future. This talk will explore how recent research innovation can be used to support decision making, taking some examples of recent research at the University of Edinburgh.

Short bio
Lindsay Beevers is Professor of Environmental Engineering and Head of Research Institute at the University of Edinburgh. Her research is focused on the future evolution of hydro-hazards (floods and droughts) as a result of climate change; and the implication these may have on society and the environment. She has over 20 years’ experience in industry and academia working on river basins across the globe.

Sandwiches offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
08/11/2023 @ 12:00 room CE 0 94.1

Hybrid Workshop on Open Education

EPFL promotes the unrestricted sharing of research findings by its scholars, aligning with its commitment to Open Science. Within the Center for Digital Education, we are of the opinion that Open Education has the potential to contribute significantly to Open Science. Through (video) lectures and (interactive) exercises, we can effectively disseminate the insights gained from scientific research, enabling researchers to acquire the skills and knowledge needed to utilise open data sets and tools. Furthermore, we are confident that, given the current technological landscape, a substantial portion of our educational activities can easily extend beyond traditional classroom settings with minimal additional effort. This is why we advocate for the accessibility of publicly funded education to the broader public.

This hybrid workshop will demonstrate Open Education and open a discussion on how you can open up your teaching materials, including videos, quizzes, slides, and other resources, by licensing them under Creative Commons. We will cover legal and technical considerations, using third-party materials, quality management and maintenance of open resources, and adopting interoperable formats, among other topics.

We encourage you to bring your own course materials - start with your MOODLE page, or your mediaspace.epfl.ch channel - to discover the difference between viewing rights and copyrights, what to consider when selecting a CC license, etc.
14/11/2023 @ 11:00 room BC 04

What’s In My Big Data? Connecting Between Data and Models Behavior

Yanai Elazar is a postdoctoral researcher on the AllenNLP team at AI2, and the University of Washington, and a Rothschild Fellow. He did his PhD (2022) in Computer Science in the NLP lab at Bar-Ilan University.

Yanai Elazar is visiting from the University of Washington to present his most recent work: "What’s In My Big Data? Connecting Between Data and Models Behavior".

Summary of the talk:
Large text corpora are the backbone of language models. However, we have a limited understanding of the content of these corpora, including general statistics, quality, social factors, and inclusion of evaluation data (contamination).
In this work, we introduce What's In My Big Data? (WIMBD), a platform and a set of 16 high-level analyses that allow us to reveal and compare the contents of large text corpora. WIMBD builds on two basic capabilities---count and search---at scale, which allows us to analyze more than 35 terabytes on a standard compute node.
We apply WIMBD to 10 different corpora used to train popular language models, including C4, The Pile, and RedPajama. Our analysis uncovers several surprising and previously undocumented findings about these corpora, including the high prevalence of duplicate, synthetic, and low-quality content, personally identifiable information, toxic language, and benchmark contamination. For instance, we find that about 50% of the documents in RedPajama and LAION-2B-en are duplicates. In addition, several datasets used for benchmarking models trained on such corpora are contaminated with respect to important benchmarks, including the Winograd Schema Challenge and parts of GLUE and SuperGLUE.
We then discuss follow-up research projects we did using WIMBD, studying different model behaviors originating from the data.

Organized by Antoine Bosselut, NLP lab
17/11/2023 @ 12:00 room

CESS Seminar : Reuse and repurpose applications for end-of-life large scale wind turbine blades

Prof. Robert Böhm (HTWK Leipzig)

Abstract
In order to establish a circular economy in accordance with the EU's "Green Deal", closed material cycles must be established in lightweight engineering for components made of fibre reinforced polymers (FRR), such as wind turbine rotor blades or aircraft components. This is accompanied by the demand for reuse of the FRP, for which various approaches are proposed, including reuse, repair, refurbish, remanufacture, repurpose or recycling (R6 strategy). While numerous recycling processes have been scientifically and technologically investigated in recent years, relevant questions regarding the reuse or repair of large FRP structures remain largely unanswered. The presentation discusses first approaches to overcome the current deficits. Relevant topics include: (i) how can end-of-life (EoL) structures be dismantled ?, (ii) what are the properties of FRPs when they reach the EoL phase and how should damage within the structures be handled ?, and (iii) what challenges have to be tackled during reuse / repurpose conception ? The presentation will also show several interesting examples.

Short bio
Prof. Böhm received his Diploma in Civil Engineering from TU Dresden (Germany) in 2001 and his PhD in Composite Material Science in 2008 (TU Dresden, Institute of Lightweight Engineering and Polymer Technology). After a Post-Doc period, he habilitated in 2017 on damage tolerant design of composite structures. Since 2020 he is Full Professor for Composite Lightweight Engineering at HTWK Leipzig, Germany. He is Executive Board Member of the Lightweight Alliance Saxony and Member of several national and international research clusters. He received the IAAM Award “Advancement of Materials” from the International Association of Advanced Materials (Sweden) in 2020 and the Dresden Excellence Award by the City of Dresden and the TU Dresden in 2017. Prof. Böhm works on multifunctional composites, experimental diagnostics of composites, modelling and simulation of composites with the focus on damage, and on the development of conventional and renewable, resource-efficient composite materials.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
21/11/2023 @ 11:00 room BC 04

NLP seminar: Retrieving Texts based on Abstract Descriptions

Shauli Ravfogel (Bar-Ilan University)

Shauli Ravfogel, from Bar-Ilan University, is presenting his most recent work on Retrieving Texts based on Abstract Descriptions.
You can join in BC 04 or online.

This talk aims to connect two research areas: instruction models and retrieval-based models.

Abstract:
While instruction-tuned Large Language Models (LLMs) excel at extracting information from text, they are not suitable for semantic retrieval. Similarity search over embedding vectors allows to index and query vectors, but the similarity reflected in the embedding is sub-optimal for many use cases. We identify the task of retrieving sentences based on abstract descriptions of their content.
We demonstrate the inadequacy of current text embeddings and propose an alternative model that significantly improves when used in standard nearest neighbor search. The model is trained using positive and negative pairs sourced through prompting a large language model (LLM). While it is easy to source the training material from an LLM, the retrieval task cannot be performed by the LLM directly. This demonstrates that data from LLMs can be used not only for distilling more efficient specialized models than the original LLM, but also for creating new capabilities not immediately possible using the original model.

Organized by Antoine Bosselut (NLP lab)
23/11/2023 @ 11:00 room GR A3 32

Models and algorithms for transit centric urban mobility

Prof. Samitha Samaranayake

Abstract
Affordable, equitable and efficient access to personal mobility is a fundamental societal need---with broad implications for personal well-being, economic mobility, education, and public health. While shared mobility, autonomy and electrification seem to be getting most of the attention in the research community and industry (at least in the US), it is hard to envision a transportation system that is sustainable, equitable and scalable without a significant mass-transit component. This raises many interesting questions on when and how new technologies (e.g., mobility-on-demand services) can be integrated with mass transit to improve personal mobility. This talk will focus on some algorithmic and practical questions related to designing and operating such integrated multi-modal transit systems. We will discuss the problem setting at a high-level and talk about some specific algorithms for (bus) line-planning in the multi-modal setting (including line generation). We will also have some discussion on equity considerations if time permits.

Short bio
Samitha Samaranayake is an Assistant Professor in the School of Civil and Environmental Engineering at Cornell University with graduate field faculty affiliations in Operations Research and Information Engineering, the Center for Applied Mathematics, and Systems Engineering. His primary research interest is in the modeling, analysis and control of transportation systems with a focus on societal considerations such as sustainability and equity, and developing computationally efficient solution techniques and algorithms that enable practical applications. He received an NSF CAREER Award in 2021. Prior to joining Cornell he was a Postdoctoral Associate in the Laboratory for Information and Decision Systems at MIT. He completed his Ph.D. in Systems Engineering at the University of California, Berkeley in December 2014. He has worked in the server technologies group at Oracle, the design for test (DFT) group at Synopsys, the route planning/transit team at Google and the French National Institute for Research in Computer Science and Control (INRIA). Samitha received his Bachelors and M.Eng. in Computer Science from MIT and an M.Sc. in Management Science and Engineering from Stanford University.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
24/11/2023 @ 12:15 room GC B3 31

Oscillation and atomization process of a liquid film induced by gas flows

Prof. Ippei Oshima

Abstract
In nature and many applications, a liquid is atomized by the surrounding gas flow. On the way, gas flow interacts with the liquid, which results in droplets. The spray characteristics of a liquid film by the gas flows are particularly significant because the film break up can generate many tiny droplets. However, the phenomena have not been unclear because of its complicated multi-scale and multi-phase characteristics. As one of the applications, we mainly focus on the atomization process of an air-blasted liquid film, which involves many essences for fluid dynamics and multi-phase flow.

In this presentation for a wide range of audiences, I will briefly explain (1) how the liquid film deformation is caused by the effect of the gas-liquid interaction and (2) how the above deformation process produces droplets with various sizes.

Short bio
Dr. Ippei Oshima obtained a Ph. D in Engineering at Kobe University, Japan, in 2019. From that year, he worked as a Postdoctoral researcher at Japan Agency for Marine-Earth Science and Technology for two years. In 2021, he moved to Institute of Fluid Science, Tohoku University, as an Assistant Professor.

Sandwiches offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
01/12/2023 @ 12:15 room GC B1 10

CESS Seminar : Stability Problems in Mechanics: Multiphysics & Multiscale Aspects (A Mechanician’s Perspective…)

Prof. Nicolas Triantafyllidis, École Polytechnique, Palaiseau

Abstract:
Stability is a fascinating topic in solid mechanics that has its roots in the celebrated Euler column buckling problem, which ﬁrst appeared in 1744. Over the years advances in technology have led to the study of ever more complicated structures, ﬁrst in civil and subsequently in mechanical engineering applications. Aerospace applications, most notably failure of solid propellant rockets, led the way in the 1950s. Problems associated with materials and electronics industries came on stage in the 1970s and 1980s, starting with instabilities associated with thin ﬁlms and phase transformations in shape memory alloys (SMA’s), just to name some of the most preeminent examples. In a parallel path, starting in the late 19th century, mathematicians studying nonlinear diﬀerential equations, developed the concept of a bifurcation (term coined by Poincare) and created powerful techniques to study the associated singularities, followed by advances in group-theoretical methods that exploit the problem’s underlying symmetries. Amazing progress has been made since the early days of structural buckling problems and continues to be made in this ﬁeld, with applications ranging from atomistic to geological scales. With the advent of new materials, the number of applications in this area continues to progress with an ever- increasing pace.

In this talk we present selected applications of stability problems involving phenomena a) across spatial scales and b) driven by multi-physics coupling. In the first class of applications, we visit – by decreasing the size of the underlying scale – the instabilities occurring in fiber reinforced composites, honeycomb, and crystal lattices (shape memory effects). In the second class, we present stability problems in magnetoelastic thin films, liquid crystals, and step-bunching in epitaxial thin film deposition. In all these applications, we use both continuum description of the problem at hand or appropriate micromechanical models and the mathematical tools of bifurcation theory and symmetry groups.

Short bio
Prof. Nicolas Triantafyllidis obtained a Ph.D. in Engineering and an MS in Applied Mathematics from Brown University in 1980. The same year he joined the faculty of the Aerospace Engineering Department at the University of Michigan in Ann Arbor, MI, USA starting as an Assistant Professor and reaching the rank of Full Professor in the Departments of Aerospace Engineering and Mechanical Engineering & Applied Mechanics. He is currently an emeritus Professor of the University of Michigan. In 2009 he moved to France to become CNRS Director of Research in the Solid Mechanics Laboratory (LMS) and a Professor of Mechanics at the Ecole Polytechnique, where he is currently a member of the Haut College.

Prof. Triantafyllidis’ research is in the area of nonlinear continuum mechanics of solids and structures with emphasis on stability, scale effects and Multiphysics aspects. More specifically he has worked on the following topics: Numerical methods (FEM); Finite strain problems in elasticity and plasticity related to metal forming; Failure mechanisms in composites and architected materials; Group theoretical methods in bifurcation and stability; Multi-scale problems and related stability issues in solid mechanics; Phase transformations in SMA’s; Magneto-electro-mechanical coupling problems in solids; Electromagnetic forming and associated stability problems; Stability of solids under high rates of strain; Mechanical effects in semiconductors; Stability of structures under high strain rates; Magneto-rheological and nematic elastomers; Liquid crystals, Epitaxial growth on crystals and associated stability problems; Finite strain chemo-poro-mechanics and subcutaneous injection modeling.

Prof. Triantafyllidis has developed and taught a number of graduate and undergraduate courses in solid mechanics in the topics of stability of solids, micromechanical theories of solids (homogenization techniques), plate and shell theories, numerical techniques (finite elements), shape memory alloys and coupled mechanical-electromagnetic field theories. He has supervised the Doctoral Theses of several graduate students in the US and France. In addition, Prof. Triantafyllidis has collaborated extensively with researchers on both sides of the Atlantic and has served, through different functions, the international solid mechanics community.

Sandwiches offered after the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
04/12/2023 @ 14:00 room ELE 111

Smart Publishing

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage?

In this workshop, which will be held in presence only, we will address the publication process in the current context:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders' Open Access policy
• Know and protect your rights as an author according to EPFL’s policy
• Get to understand what a publishing contract entails.

Organized by EPFL Library
08/12/2023 @ 12:15 room GC B1 10

CESS Seminar : Second Generation of Eurocode 2: Concrete Structures. 2023

Dr. Hans Rudolf Ganz, Past Chair CEN TC250 SC2
Abstract
The first generation of Eurocodes, published between 2004-2007, has been under revision since 2015. The second-generation Eurocode 2 has been approved for publication by CEN in June 2023. The presentation will briefly inform on the process and organisation for the revision of Eurocodes and preparation of Eurocodes 2^nd Generation, in general. The presentation will then illustrate some general changes made to Eurocode 2 with respect to structure of the standard, design models and considering sustainability, etc. This is followed by highlighting some of the most important changes made to main Clauses / design provisions of Eurocode 2, Part -1-1, General rules for buildings, bridges and civil engineering structures. Some brief information on main changes in future Eurocode 2, Part -1-2, Structural fire design will be given also. The presentation will end with an outlook on the next steps until the introduction of the 2^ndGeneration Eurocode 2 in the countries and practice.

Short bio
- Civil engineer, graduated from ETH Zurich Diploma for Civil Engineering ETH : 1978
- Dr. sc. techn. ETH Zurich : 1985 (Masonry shear wall)
- 1985-1988: Structural engineer, VSL International Ltd., Berne, Switzerland
- 1989/1990: Technical advisor, VSL Corporation, Campbell/CA, US
- 1990-2011: Chief Technical Officer, VSL International Ltd., Berne / St. Quentin-Yvelines (France) / Berne in charge of 3 Technical Centres in USA, Europe and Asia; Research & Development; QA; VSL Academy (training of personnel)
- 2011-present: Ganz Consulting (owner) – supporting owners with questions to prestressed concrete and masonry structures; technical assessment of prestressing systems; etc.
- Chairman of SIA committee on SIA Structural Standards (mirror committee to CEN/TC 250); member of Concrete Standards committee SIA 262
- Past chairman of CEN/TC 250/SC 2 Eurocode 2 Concrete Structures (2014 – 2023)
- Honorary fib president and past chair of fib Commission on reinforcing and prestressing systems (1998-2007); member of several fib Commissions and Task Groups
Sandwiches offered after the seminar.
Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
06/03/2024 @ 11:00 room GC B1 10

CESS seminar : Deviated Fixed-route Microtransit: Design and Operations

Prof. Alexandre Jacquillat, MIT Sloan School of Management

Abstract
Microtransit offers opportunities to enhance urban mobility by combining the reliability of public transit and the flexibility of ride-sharing. This paper optimizes the design and operations of a deviated fixed-route microtransit system that relies on reference lines but is allowed to deviate in response to passenger demand. We formulate a Microtransit Network Design (MiND) model via two-stage stochastic optimization. The model features a tight second-stage formulation thanks to a subpath-based representation of microtransit operations in a load-expanded network, which optimizes on-demand deviations between checkpoint stops. We develop a double-decomposition algorithm combining Benders decomposition and subpath-based column generation armed with a tailored label-setting algorithm. Using real-world data from Manhattan, results suggest that our method scales to large practical instances, with up to 10-100 candidate lines and hundreds of stops. Comparisons with transit and ride-sharing benchmarks suggest that microtransit provides win-win outcomes toward efficient mobility (high demand coverage, low operating costs, high level of service), equitable mobility (broad geographic reach) and sustainable mobility (limited environmental footprint).

Short bio
Alexandre Jacquillat is an Associate Professor of Operations Research and Statistics at the MIT Sloan School of Management. His research focuses on data-driven decision-making, spanning integer optimization, stochastic optimization, and machine learning. His primary focus is on the optimization of complex transportation and logistics systems to promote efficient, reliable and sustainable mobility of people and goods. Alexandre is the recipient of several awards, including the INFORMS Dantzig Dissertation Award, the Best Paper Prize from INFORMS Transportation Science and Logistics (twice), the Harvey Greenberg Research Award from INFORMS Computing, the Pierskalla Best Paper Award from INFORMS Health Applications, and the Best Paper Award from INFORMS Data Mining and Decision Analytics. He received a Master of Science in Applied Mathematics from the Ecole Polytechnique and PhD in Engineering Systems from MIT.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
15/03/2024 @ 12:15 room GC B1 10

CESS seminar : ML-enhanced approaches to help accelerate materials design for extreme environments

Prof. Lory Brady Graham-Brady, Johns Hopkins University

Abstract
Machine learning and AI-driven approaches to evaluating materials provide a highly efficient alternative to physics-based computational modeling; however, they often suffer from reduced accuracy and limited interpretability. Even with these potential limitations, the results may be sufficient in materials design to identify material chemistries and microstructures that merit further exploration. Such data-driven approaches are enabled by recent advances in high-throughput experimental techniques that offer exciting opportunities to generate statistically significant quantities of materials characterization data. Similar trade-offs are found in high-throughput experiments, which may miss some of the relevant physics but provide an assessment of whether material performance changes when moving from one specimen to another. By providing a rapid evaluation of new materials, machine learning models support accelerated screening and decision-making for control and optimization of high-throughput processes on the path to materials design. This talk will provide an overview of the AI for Materials Design (AIMD) facility at Johns Hopkins, which highlights some of the challenges, pitfalls and opportunities inherent in an integrated high-throughput and automated materials design framework, in particular addressing challenges associated with assessing high-temperature, high-rate and high-pressure environments. The role of machine learning models in guiding this automated materials design is highlighted and discussed in the context of a few example applications.

Short bio
Lori Graham-Brady is a Professor and former Chair of the Civil and Systems Engineering Department at Johns Hopkins University, with secondary appointments in Mechanical Engineering and Materials Science & Engineering. Her research interests are in AI for materials design, computational stochastic mechanics, multiscale modeling of materials with random microstructure and the mechanics of failure under high-rate loading. She is the Director of the Center on AI for Materials in Extreme Environments, Associate Director of the Hopkins Extreme Materials Institute and previous Director of both an NSF-funded IGERT training program with the theme of Modeling Complex Systems, and the Center for Materials in Extreme Dynamic Environments. She has received a number of awards, including the Presidential Early Career Awards for Scientists and Engineers (PECASE), the Walter L. Huber Civil Engineering Research Prize, and the William H. Huggins Award for Excellence in Teaching.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
22/03/2024 @ 12:15 room GC B1 10

CESS Seminar : Valeur immatérielle des ouvrages d’arts

Dr. Damien Dreier, Structurame

Résumé
Quel est la valeur de nos ouvrages d’art ?

La réponse à cette question est assez simple si l’on ne considère que les coûts de construction et de maintenance.
Par contre, il devient difficile de répondre à cette question lorsque on élargit l’évaluation de la valeur de nos ouvrages en intégrant la valeur immatérielle. C’est-à-dire, la valeur d’utilisation, la valeur de qualité du bâti, la valeur symbolique, la valeur artistique, la valeur patrimoniale, la valeur environnementale, …

Cet exposé tentera, à travers des projets et études récentes, de présenter le rôle primordial de la conception et de la préservation en lien avec la valeur immatérielle des ouvrages d’arts.

Cette présentation sera donnée dans le cadre conjoint des Civil Engineering Seminar Series de l’Institut d’ingénierie civile de l’EPFL et de la série de conférence de la société pour l’art de l’ingénieur (Gesellschaft für Ingenieurbaukunst).

CV
Né à Genève en 1982, de nationalité suisse, Damien Dreier débute des études en génie civil à l’EPFL en 2001. Ses études à l’EPFL s’achèvent par un travail de Master en 2006 sous la supervision du Prof. Dr Aurelio Muttoni et du Dr Jean-François Klein du bureau Tremblet (à présent T).

Une thèse de doctorat à l’ibeton – EPFL, supervisée par le Prof. Dr Aurelio Muttoni, sur l’interaction sol-structure dans le domaine des ponts intégraux suivra entre 2006 et 2010. Il réalise une première expérience pratique entre 2011 et 2013 chez T-ingénierie (à présent T) sous la direction du Dr Klein et de Pierre Moïa. Ce travail lui permettra de prendre part à des projets de grande ampleur comme, entre autres, la construction du 3ème pont sur le Bosphore.

En 2014, en association avec le Dr Luis Borges, il fonde le bureau structurame à Genève et Lausanne. structurame a été fondé avec pour objectif de développer quatre axes principaux. Axes que nommé l’architecture structurale, l’ingénierie structurale, la recherche structurale et le développement durable structural. L’idée principale étant de prôner une approche où l’ingénieur structure est un acteur du projet au sens large.

Ses activités professionnelles sont combinées avec des charges d’enseignement à l’ibeton - EPFL entre 2011 et 2023 et à la HES-SO - hepia depuis.

Des sandwiches sont offerts à la fin du séminaire.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
11/04/2024 @ 16:15 room MED 0 1418

MEchanics GAthering –MEGA- Seminar: On the necessity of curation for datasets to achieve FAIR standard goals in scientific publications

Guillaume Anciaux (LSMS, EPFL)

Abstract: Academic knowledge is traditionally disseminated by academic journals. However, nowadays, the production of scientific data in any given project exceeds by a vast amount what can be contained in a few journal pages. Reproducible scientific data and publications must be associated to boost scientific collaborations and discoveries. There is today an always increasing pressure coming from universities and funding institutions towards publishing open data, despite the important workload it represents. Thus far, only limited solutions/tools to curate and share data produced by experiments and simulations. At large, this situation does not favor open science.
In this presentation, I will start with a small history of the academic press, up to the diamond open access principles and the role that can be played by scientists themselves. Naturally the evolution of practices towards digitization and computational disciplines will bring us to consider datasets. The possibilities and the rather limited curative requirements for datasets in generalist repositories such as Zenodo will be detailed.
I also will present the recent initiative of the overlay diamond open access "Journal of Theoretical, Computational and Applied Mechanics" towards the curation of the datasets accompanying published paper. Just like for the paper review procedure, it is believed that datasets can only become valuable when correctly cleaned, annotated, documented and proved with minimal reproducibility. The JTCAM could make this move thanks to the Dissemination of Computational Solid Mechanics (DCSM) project, which aimed at developing a web platform and an open-source software (Solidipes) to support scientists when curating and publishing their datasets. Such a platform will be briefly presented and illustrated with show case papers+datasets.
Finally, the ideal curation framework will be sketched. In particular, the need for specific ontologies, describing the relational hierarchy between objects, will be linked with robust and simplified recognition/validation procedures. In other terms, a normalization of the (discipline dependent) scientific community output is called for. While this certainly represents an important amount of work, it has the potential of reducing the workload for dataset curators, which is a sine qua non condition to convince dataset reviewers to highlight our digital production.

Bio: Guillaume Anciaux got his master's from the Graduate School in Electronics, Computer Sciences, Telecommunications, Mathematics and Mechanics (ENSEIRB-MATMECA), Bordeaux, France, with a Computer Science degree in 2003. Then, he started his PhD in 2003 with Prof. Coulaud and Prof. Roman in the High Performance Computing team ScAlApplix at INRIA (Bordeaux, France). His Ph.D work focused on multiscale concurrent coupling methods to bridge molecular dynamics with finite elements. He then joined the team of J.F. Molinari at EPFL, where he explored computational solid mechanics, for various scales, models, and computing architecture. In particular, contact mechanics, tribology, and material defects were topics he contributed to during the past decade. More recently, G. Anciaux worked on promoting Open Research Data to mechanics disciplines. For instance he got involved in the editorial board of the Diamond Open Access journal JTCAM, with the goal to introduce dataset curation to the publishing procedure of the JTCAM.

Organized by MEGA.Seminar Organizing Committee
18/04/2024 @ 11:00 room CM 0 13

CESS Seminar : Flexible Bus Service Design under Spatial and Temporal Demand Uncertainty

Prof. Hong K. LO, GREAT Smart Cities Institute of the Hong Kong University of Science and Technology

Abstract
Zonal-based flexible bus service (ZBFBS) is a class of demand responsive door-to-door transit service, wherein the service area is divided into zones and services are arranged via zonal routes with detours within each zone to pick up and drop off passengers. Service requests are aggregated by zonal OD pairs, time windows, and the number of passengers per request. This presentation will address the design of ZBFBS with the stochastic programming approach to account for passenger demands’ spatial (origin-destination or OD) and volume stochastic variations over time. Two types of two-stage stochastic problems with recourse are formulated, one for the frequency-based approach to maximize the expected profit minus detour cost, and one for the schedule-based approach to include the time dimension. Finally, a bi-level framework is proposed to jointly optimize the zonal design and flexible bus service strategy. The zonal design and ZBFBS strategy are validated in instances constructed based on real data in Chengdu, China.

Short bio
Professor Hong K. LO is Dean of Engineering, Chair Professor of Civil and Environmental Engineering, and Director of GREAT Smart Cities Institute of the Hong Kong University of Science and Technology. His expertise includes dynamic transportation system modeling, traffic control, network reliability, and public transportation analysis. He has published extensively in the transportation literature and was selected as one of the Most Cited Researchers in Civil Engineering in the Academic Ranking of World Universities (ARWU). Professor Lo is very active in the transportation community, for instance, elected as Convener of the International Scientific Committee of the conference series Advanced Systems for Public Transportation (CASPT), serves as Founding Editor-in-Chief of Transportmetrica B: Transport Dynamics, Managing Editor of Journal of Intelligent Transportation Systems, and on the editorial boards of many international journals. Professor Lo was awarded the prestigious triennial World Conference on Transportation Research (WCTR) Prize and Eastern Asia Society for Transportation Studies (EASTS) Outstanding Paper Award, and HKUST School of Engineering Research Excellence Award.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
19/04/2024 @ 12:15 room GC B1 10

CESS Seminar : Multi-scale highway traffic flow modeling and analysis

Dr Qixiu Cheng, University of Bristol Business School

Abstract
In this talk, we will introduce the concept of self-consistency in macro and micro traffic flow modeling and analysis. First, we will introduce a new s-shaped three-parameter (S3) traffic flow model, which could maintain the consistency between the fundamental diagram (FD) model and the car-following model. Second, we will extend the deterministic FD to stochastic fundamental diagrams (SFDs) and introduce an analytical and quantitative method for analyzing traffic state variations. We investigated the scattering effect in the FD and proposed two SFD models with lognormal and skew-normal distributions to explain the variations in traffic states. Finally, the different calibration approaches at the macro and micro levels may lead to misaligned parameters with identical practical meanings in both macro and micro traffic models. This inconsistency arises from the difference between the parameter calibration processes used in macro and micro traffic flow models. Hence, we proposed an integrated multiresolution traffic flow modeling framework using the same trajectory data for parameter calibration based on the self-consistency concept. We conducted experiments using real-world and synthetic trajectory data to validate our self-consistent calibration framework.

Short bio
Dr Qixiu Cheng is a Lecturer at the University of Bristol Business School. He received his Ph.D. degree in transportation engineering from Southeast University, Nanjing, China in 2021. Before his current position, he was a Postdoctoral Fellow and then promoted to a Research Assistant Professor at The Hong Kong Polytechnic University from 2021 to 2023. His research interests include transport network modeling and optimization, micro and macro traffic flow theory, and transport big data analytics and urban informatics. His work has been published in Transportation Research Part B/C/E, European Journal of Operational Research, IEEE Transactions on Intelligent Transportation Systems, Computers & Operations Research, and Expert Systems with Applications.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
01/05/2024 @ 12:00 room AI 1153

Discover OMERO

Lucie Bracq, Van der Goot Lab -
Georgios Hatzopoulos, Gönczy Lab -
Romain Guiet, BIOP

Store your imaging data in a secure reproducible manner using the EPFL OMERO server.
Discover functionality and see use cases from early adopters.

Organized by Rémy Dornier, BIOP
Romain Guiet, BIOP
Arne Seitz, BIOP
02/05/2024 @ 13:15 room CE 1 6

NLP Seminar: Natural Language Processing for Signed Languages

Kayo Yin (UC Berkeley)

Kayo Yin, from UC Berkeley, is presenting her most recent works on Natural Language Processing for Signed Languages.
You can join in CE16 or online.

Abstract:
Signed languages are the primary means of communication for many deaf and hard-of-hearing (DHH) individuals. Since signed languages exhibit all the fundamental linguistic properties of natural language, we believe that tools and theories of Natural Language Processing (NLP) are crucial for its modeling. However, existing research in sign language processing seldom attempts to explore and leverage the linguistic organization of signed languages.
In this lecture, she will talk about why NLP researchers should include signed languages in their research, best practices for conducting sign language research, and some of the challenges in sign language processing today. She will also present two recent projects that take steps in extending NLP to signed languages: 1) modeling handshapes to analyze different pressures for communication efficiency in American Sign Language (ASL) and 2) using AI to make STEM education more accessible to DHH students.

Bio:
Kayo Yin is a second year PhD student at UC Berkeley advised by Jacob Steinhardt and Dan Klein. She currently works on LLM interpretability and sign language processing. Before that, she was a Master’s student at Carnegie Mellon University advised by Graham Neubig, and she completed her undergraduate studies at École Polytechnique in 2020. Her research has been recognized by an ACL Best Resource Paper award, an EMNLP Best Paper Honorable Mention award, an ACL Best Theme Paper award, and the Thomas Clarkson medal. She is the recipient of a Siebel Scholarship and a Future of Life PhD fellowship.

Organized by Antoine Bosselut (NLP lab)
03/05/2024 @ 12:15 room GC B1 10

CESS Seminar : New Design Strategies to Make Earthquake Resilient Steel Bridges

Prof. Michel Bruneau, University at Buffalo, USA

Abstract
The concept of resilient infrastructure, formulated nearly two decades ago, has been progressively endorsed over the years. This has happened in parallel with an at-large shift towards resilience across many disciplines. Steel structures have an advantage to achieve true resilience objectives because making steel buildings and bridges resilient earthquakes is possible using simple, effective design strategies. This session will present findings from recent research on some different ways to achieve steel structures that are highly resilient to earthquakes. This will include, as a particular focus, a bi-directional ductile diaphragms concept consisting of Buckling Restrained Braces (BRBs) to achieve damage-free columns and displacements demands that can be easily accommodated by conventional expansion joints. This behavior of this ductile diaphragm concept was investigated, a design procedure was formulated. Shake table testing of a 40’ long bridge span specimen having various configurations of bi-directional diaphragms experimentally demonstrated that the resilience objective can be achieved using this design strategy.

Short bio
Michel Bruneau is a SUNY Distinguished Professor at the University at Buffalo, a Distinguished Member of the American Society of Civil Engineers, a Fellow of the Canadian Academy of Engineering, and Emeritus Director of an NSF-funded Earthquake Engineering Center that focused on enhancing the disaster resilience of communities. He has spent more than three decades developing engineering strategies to enhance the resilience of infrastructure. His extensive body of research has been instrumental to the inclusion, in national and international standards, of specifications for multiple innovative structural systems, leading to implementation in countless structures worldwide. He has received more than 20 prestigious awards for this innovative work, including a lifetime achievement award. Dr. Bruneau has conducted numerous reconnaissance visits to disaster-stricken areas, is a member of many professional and technical code-writing committees, and has served on many expert peer review panels. He is one of the most cited researchers in structural engineering and earthquake engineering. He has authored or co-authored over 550 technical publications, including more than 180 referred journal papers, 250 papers in conference proceedings. Notably, he is the lead author of the 900-pages textbook “Ductile Design of Steel Structures,” used worldwide by structural engineers, and is the lead author of the 2003 seminal paper that has formulated a concept and expression of disaster resilience that today is at the foundation of most research on this topic.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
16/05/2024 @ 09:00 room INF 019

Smart Publishing

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage?

In this workshop, which will be held in presence only, we will address the publication process in the current context:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders' Open Access policy
• Know and protect your rights as an author according to EPFL’s policy
• Get to understand what a publishing contract entails.

Organized by EPFL Library
17/05/2024 @ 12:15 room GC B1 10

CESS : Nouvelles constructions dans le patrimoine bâti : du fond et de la forme By Dr. Thibault CLEMENT

Dr. Thibault Clément, INGPHI

Résumé de la présentation
La question de l’impact de nos constructions sur notre environnement est fondamentale, pas seulement d’un point de vue énergétique ou écologique, mais aussi sous l’angle de son intégration, de son acceptation et de sa durabilité.

S’il paraît clair que le plus grand respect de notre environnement consiste en ne pas le toucher, qu’en est-il quand il faut quand même construire ?

Cette présentation tentera, avec des exemples construits et une étude de cas réalisée par le bureau, de sonder l’importance du lien entre le fond et la forme d’une construction.

La présentation sera donnée dans le cadre conjoint des Civil Engineering Seminar Series de l’Institut d’ingénierie civile de l’EPFL et de la série de conférence de la société pour l’art de l’ingénieur (Gesselschaft für Ingenieurbaukunst).

CV
Né à Montbéliard en France en 1984, Thibault Clément débute ses études d’ingénieur en France à l’Ecole des Mines (Alès). Il fait un échange Erasmus pendant son Master à l’EPFL en 2007.

Il poursuit une thèse de doctorat à l’IBETON sous la direction du Prof. Dr Aurelio Muttoni sur l’influence de la précontrainte sur la résistance au poinçonnement des dalles en béton armé entre 2008 et 2012. En 2013, il acquiert une première expérience pratique au sein du bureau T-Ingénierie (aujourd’hui T) en s’impliquant notamment sur le projet du 3ème pont sur le Bosphore à Istanbul ou sur la couverture des quais de la gare de Lausanne.

En 2015, il intègre le bureau INGPHI à Lausanne et rejoint la direction en 2021. Il s’implique dans des projets de remise en état d’ouvrages existants en France et en Suisse, sur des expertises et développe l’activité des ouvrages étanches avec plusieurs projets de stations de traitement des eaux.

Sandwiches offerts à la fin du séminaire.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
24/05/2024 @ 12:15 room GC B1 10

CESS Seminar : Architectured and Random Microstructures : Optimization with level-set functions

Prof. Andrei Constantinescu, CNRS and Ecole Polytechnique

Abstract
Micro- and Meso-structures of both ordered and disordered media are controlling physical functions and properties materials and have received a lot of attention in the recent years triggered by the advancement in imaging and fabrication technologies.

In this talk, questions of optimal microstructures will be addressed using a level-set representation of the media and optimization techniques.

We design micro–architectured thin elastic panels or meso-architectured thick shells to control their macroscopic behavior, accounting for particular stiffness and the extension–bending coupling effects. The topology optimization method combines the Hadamard shape derivative and a level set method in the diffuse interface context to systematically capture the optimal micro-architecture of the unit cell or the meso-architecture of the structure.

We generate simple but flexible surrogate micro-structure models for two-phase materials combining the level-sets and Gaussian random fields with covariance of Matérn class. Complex random heterogeneous two-phase media can be represented by optimizing a few key design parameters estimated from a small number of real material images using Bayesian inversion.

The two methods can be combined to design the micro-architectured materials under load or material uncertainty.

Short bio
Andrei Constantinescu, holds a Directeur de Recherche and a Professor position with the CNRS and the Ecole Polytechnique, respectively. He currently heads the Laboratoire de Mécanique des Solides. Andrei received a Mathematics-Mechanics degree from the University of Bucharest, Romania (1988). He received a M.S. (1991) and a Ph.D. (1994) from Ecole Polytechnique, Palaiseau, France and his Habilitation (2005) from Université Pierre et Marie Curie, Paris, France. He had different visiting positions with Cornell University (1994), Oxford University (2001), Tokyo Institute of Technology (2008), ETH-Zürich (2015-2016) and was on an industrial leave with PSA Peugeot-Citroen in 2002. He received the Doisteau-Emile Blutet Prize of French Academy of Sciences. He is currently involved in several academic and industrial projects on the additive manufacturing of polymers and metals.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
07/06/2024 @ 12:15 room GC B1 10

CESS Seminar : Strut-and-Tie Method : Recent Advances and US Bridge Design Code Provisions

Prof. Oguzhan Bayrak, University of Texas at Austin

Abstract
The strut-and-tie method (STM) has become a fundamental approach for designing D-regions in reinforced concrete members for its simplicity, rationality, and conservatism. A comprehensive research program, supported by the Texas Department of Transportation (TxDOT), has further refined the accuracy and applicability of STM to bridge elements through large-scale structural experiments and in-depth analyses across four major aspects: (i) Tri-axially tensioned nodes, (ii) curved-bar nodes, (iii) nodal confinement, and (iv) crack control reinforcement detailing.

The study on drilled shaft reinforcement behavior under tri-axial tension proposed novel design expressions for anchorage and available anchorage length checks, utilizing a 3D fan-shaped compression zone approach observed in tests.

Insights from testing curved-bar nodes within closing knee joints underscored the significance of appropriate bend radius for longitudinal reinforcement at the outside of joints, with proposed design expressions for various scenarios to fully develop the reinforcing bars and prevent premature joint failures.

Deep beam tests revealed a 10% enhancement in nodal zone strength when both nodal zones of a strut are adequately provided with confining reinforcement, alongside of well-defined detailing methods, which are the first reported guidelines in literature for nodal confinement.
Deep beam tests regarding crack control reinforcement spacing advocate for potential modifications in design provisions. Test results suggested relaxation from the current specifications without compromising conservatism while maintaining the STM's predictive ability, reducing congestion, and improving constructability.

Advancing our understanding and refining STM-based design approaches ensures confidence in the application of the STM on reinforced concrete members, thereby potentially influencing future Model Code developments within the International Federation for Structural Concrete (fib).

Short bio
Oguzhan Bayrak is a distinguished teaching professor, holder of the Cockrell Family Chair in Engineering No.20, and a faculty member in the Department of Civil, Architectural and Environmental Engineering at the University of Texas at Austin. His research and teaching interests are related to the behavior, analysis and design of reinforced and prestressed concrete structures, bridge engineering, evaluation of structures in distress, structural repair, and evaluation of aging effects.

Bayrak’s research on concrete bridges has been widely referenced by the American Association of State Highway and Transportation Officials’ Bridge Design Specifications. Notably, the Strut-and-Tie Modeling (STM) design provisions of this document is largely based on the findings developed by Bayrak’s research group.

Bayrak serves as the inaugural director of the Concrete Bridge Engineering Institute (CBEI) at the University of Texas. The mission of CBEI, a national center of excellence, is to serve the concrete bridge community as the leading resource on the most pressing issues encountered in concrete bridges across the U.S. In addition, Bayrak serves as the director of the Phil M. Ferguson Structural Engineering Laboratory at the University of Texas.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
12/09/2024 @ 07:00 room Rolex Learning Center

Document selection : 56 books to succeed in your studies

The EPFL Library has selected the back-to-school Essentials for you!
Key books for all the major stages of your studies: from your first year of a Bachelor’s degree to writing your thesis, available for borrowing at the Library all year round.

To get the semester off on the right foot and support you throughout your studies: (re)learn how to study, organize your ideas and schedules, understand your brain to reach your full potential, master public speaking and speed reading.

Discover this selection online, and from from September 12 to September 26 at EPFL Library’s Espace Découverte.
It will then be on display from September 26 to October 24 in the Science Zone for all. Usual conditions apply for book loan.

Organized by EPFL Library
13/09/2024 @ 11:00 room Fribourg - Bâtiment B, Salle Douglas

CESS : Smart City Innovations and Experiments using New Climate and Energy Simulations (SCIENCES)

Dr. Miguel Martin, Delft University of Technology (Netherlands) and Carnegie Mellon University (United States)

Abstract
Climate change is considered as a major threat to any organism on Earth for the years to come. This hazard could considerably be mitigated if energy consumed by buildings was drastically reduced using either active or passive strategies. From this observation, the European Commission has made one of its top missions to support all cities in becoming climate neutral and smart by 2050.

As a contribution to this mission, the SCIENCES project aims at exploring modern approaches using both physics and artificial intelligence to simulate interactions between buildings and their outdoor conditions at the neighborhood scale through a city digital. This objective intends to be achieved by first studying methods to automatically generate detailed building energy models from a 3D city model. Detailed building energy models are then used to test different simulation techniques either by coupling them with a data driven urban canopy model or by using them to train a full artificial intelligence-based model. At the end, it is expected to use partial or full artificial intelligence-based models to predict impacts of buildings on urban heat islands and climate change over the horizon between 20 and 30 years from now. The predictions are expected to be used as guidance for architects and urban planners to better support European cities in their green and digital transition.

Short bio
Dr. Miguel Martin is currently a Marie Curie postdoctoral fellow conducting his research at the Delft University of Technology (Netherlands) and Carnegie Mellon University (United States) under the sponsorship of the European Commission. Before being granted the Marie Curie Global Fellowship, he was research engineer at the Masdar Institute of Science and Technology in Abu Dhabi (United Arab Emirates). At that time, he worked on physically based modelling approaches to simulate interactions between a building and its outdoor environment. To improve simulations of anthropogenic heat releases and countermeasures to urban heat islands using physically based models, he studied methods to assess the outdoor conditions using computational fluid dynamics during his Ph.D. at the National University of Singapore (Singapore). After his Ph.D., he joined the Berkeley Education Alliance for Research in Singapore (Singapore) as a senior research fellow to analyse urban heat fluxes from thermal images collected from a rooftop observatory. He now tries to use all his accumulated experience in urban building energy modelling and outdoor field experiments to see how artificial intelligence could help in improving the temporal resolution and time horizon with which interactions between buildings and their outdoor environment can be simulated and studied at the neighborhood scale through a city digital twin.

More information

The seminar will be followed by a reception.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
18/09/2024 @ 12:15 room GC B1 10

CESS Seminar : Mechanics of Rapidly Compacted Granular Materials Across Length Scales: Insights from X-ray Imaging and Modeling

Prof. Ryan Hurley, Associate Professor of Mechanical Engineering, Johns Hopkins University

Abstract
Granular materials are subjected to high pressures and strain rates during geophysical processes and in engineering and defense applications. The mechanics of granular materials under these conditions is complex and involves a combination of microscopic processes such as grain breakage and meso- and macroscopic processes such as deformation banding. Constitutive models used to predict responses to impact and penetration are increasingly making use of our knowledge of how microscopic and mesoscopic processes progress. Here, we discuss efforts to understand and predict rapid compaction and penetration of dry and fully saturated granular materials at length scales ranging from individual grains and pores to bulk scales. We primarily focus on experimental developments and their connections to continuum constitutive models. We first discuss small-scale planar compaction experiments which leverage x-ray imaging and time-resolved x-ray phase contrast imaging. These experiments are combined with digital twin modeling to quantify pore collapse, stress concentrations, and dynamic force chains in 3D at the grain scale. We then discuss penetration experiments at the bulk scale which employ flash x-ray imaging and a novel method of 3D flow field reconstruction. Bulk scale experiments are compared with a continuum constitutive model uniquely informed by other tests which quantify grain-scale processes such as a grain breakage. The audience will leave the talk with an appreciation of how in-situ imaging and analysis can be used to inform our understanding of and modeling capabilities for dynamic processes in granular materials.

Short bio
Ryan Hurley is an Associate Professor in the Department of Mechanical Engineering with a secondary appointment in the Department of Civil and Systems Engineering, and a Faculty Fellow of the Hopkins Extreme Materials Institute at the Johns Hopkins University (JHU). Before joining JHU in 2018, Ryan received his Ph.D. in Applied Mechanics from Caltech and worked as a postdoc in computational geomechanics at Lawrence Livermore National Laboratory. Ryan has received a 2017 Department of Energy’s Secretary’s Appreciation Award, a 2020 NSF CAREER Award, a 2021 Army Education Outreach Program’s Mentor of the Year Award, and a 2022 Air Force Office of Scientific Research (AFOSR) Young Investigator Program Award. Ryan’s research interests include studying the deformation and failure mechanisms of granular materials, rocks, and concrete using advanced experimental techniques, such as in-situ x-ray imaging and diffraction, constitutive modeling, and micromechanics.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
20/09/2024 @ 12:15 room GC B1 10

Eco-morphodynamic carbon pumping of the world’s large tropical rivers

Dr Luca Salerno, Politecnico di Torino

Abstract
The eco-morphodynamic activity of large tropical rivers interacts with riparian vegetation causing implications for the carbon cycle within inland waters. Through a multi-temporal analysis of satellite data spanning the years 2000–2019, we analyzed rivers exceeding 200 m in width across the tropical regions, revealing a Carbon Pump mechanism driving an annual mobilization of 12.45 million tons of organic carbon. River morphodynamics is shown to drive carbon export from the riparian zone and to promote net primary production by an integrated process through floodplain rejuvenation and colonization. The study identifies fluvial eco-morphological signatures as proxies for carbon mobilization, emphasizing the link between river migration and carbon dynamics. Our findings are instrumental in determining the carbon intensity of future hydropower dams, thereby contributing to informed decision-making in the realm of sustainable energy infrastructure. This study elucidates the intricate relationships that govern the nexus of tropical river dynamics, riparian ecosystems, and the global carbon cycle.

Short bio
Luca Salerno is a researcher at the Department of Environmental, Land, and Infrastructure Engineering at the Politecnico di Torino, where he earned his Ph.D. in 2022. His research focuses on the interaction between fluvial morphodynamics and tropical riparian vegetation, particularly their role in the fluvial carbon cycle. He has developed expertise in global satellite imagery analysis, remote sensing for riverine systems, and mathematical modeling, with programming proficiency on platforms such as Google Earth Engine.
Salerno's Ph.D. project applied a physically based eco-geomorphological framework to evaluate rivers' capacity to drive carbon sequestration. His work has demonstrated that river morphodynamics not only influence carbon export from riparian zones but also stimulate net primary production by rejuvenating floodplains and facilitating vegetation colonization. In a recent study, he introduced a high-resolution mapping algorithm for monitoring tropical forests in the Amazon basin, specifically applied to the Uatama River, illustrating how river regulation reshapes floodplain ecosystems, with significant implications for carbon storage and productivity.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
27/09/2024 @ 12:15 room GC G1 515

Optimal inspection, monitoring and maintenance of (civil) engineering systems

Prof. Daniel Straub

Abstract
Maintenance is key to achieving sustainable engineering systems with safe performance. As is common in engineering, much of the current practices in inspection and maintenance are the result of legacy experience, carefully adjusted based on past evidence. This has led to mostly safe but not necessarily optimal strategies. As an alternative, optimization of inspection and maintenance based on predictive modeling of the systems’ deterioration and performance has been pursued since the 1970s. In this talk, I will first summarize and discuss the fundamental principles of predictive modeling and optimization of inspection and maintenance. I will show how research and application of these methods have developed over the past 50 years and discuss the successes and challenges of these methods. I will then focus on current trends and research, which include the use of monitoring data for optimal maintenance decisions, the use of more advanced AI for prediction and optimization and the extension to optimizing maintenance actions at the portfolio or network level.

Throughout the talk, I will illustrate the concepts and methods using examples of civil engineering applications.

Short bio
Daniel Straub is a Professor for engineering risk and reliability analysis at TU München. His interest is in developing physics-based stochastic models and methods for the decision support and safety assessment of engineering systems, with a particular focus on Bayesian techniques. Daniel obtained his Dipl.-Ing. degree in civil engineering in 2000 and his PhD in 2004 from ETH Zürich. Consequently, he was a postdoc and adjunct faculty member at UC Berkeley before joining TU München in 2009. He is frequently active as a consultant to the industry on reliability and risk assessments and decision-making under uncertainty. In 2023, his work was awarded the C. Allen Cornell award, which is bestowed every 4 years by the Civil Engineering Risk and Reliability Association to an individual in recognition of outstanding contributions to the science and application of risk and reliability theory to civil engineering.

https://www.cee.ed.tum.de/era

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
04/10/2024 @ 12:15 room GC B1 10

Projeter en continuité

Roberto Guidotti, Bureau ingegneri pedrazzini guidotti

Résumé
Chaque projet, bien qu'il soit le reflet de son époque, s'inscrit dans une évolution continue de l'art de bâtir. Il est donc essentiel d'adopter un regard rétrospectif pour construire un bagage culturel qui ne se limite pas aux œuvres, mais qui repose aussi sur des méthodologies de construction ayant conduit à des solutions réalisées concrètes et convaincantes. Étant donné que le contexte est toujours unique, une œuvre ne peut être reproduite, tandis qu'une méthodologie approuvée peut être réutilisée sans anachronisme. La présentation de quelques réalisations récentes du bureau permettra d'explorer le processus appliqué à la conception structurelle.

CV
Roberto Guidotti obtient son diplôme d’ingénieur civil à la SUPSI de Lugano en 2002. Après une année d'expérience en tant qu'assistant du Prof. Massimo Laffranchi à l’Académie d’Architecture de Mendrisio et dans le bureau ingegneri Pedrazzini à Lugano, il se rend à Lausanne pour poursuivre ses études à l’EPFL. En 2007, il obtient son master en ingénierie civile, suivi de son doctorat en 2010, sous la direction du Prof. Aurelio Muttoni et du Dr Miguel Fernández Ruiz. Pendant sa recherche, il travaille à temps partiel au bureau des codirecteurs de thèse Muttoni & Fernández, Ingénieurs Conseils à Ecublens. En 2011, il retourne chez ingegneri Pedrazzini, où il devient associé, et le bureau prend alors le nom d’ingegneri Pedrazzini Guidotti. Depuis 2015, il est chargé de cours à l’Académie d’Architecture de Mendrisio, dans le domaine des structures en architecture.

Des sandwiches sont offerts à la fin du séminaire.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
11/10/2024 @ 11:00 room BC 420

Typhoon – A journey to Thailand's leading open-source LLM

Kasima Tharnpipitchai, Head of AI Strategy at SCB 10X

Discover the journey of developing Typhoon, Thailand's leading open-source large language models, created by SCB 10X – the innovation arm of Siam Commercial Bank. This talk explores approaches for overcoming low-resource challenges in dataset curation and introduces new evaluations for Thai language understanding. Learn how Typhoon optimizes for Thai language, knowledge, and culture, promoting technological self-reliance. Come exchange ideas and insights about how to support the development of open language technologies for low-resource languages.

The speaker, Kasima Tharnpipitchai, is the Head of AI Strategy at SCB 10X, with over two decades of startup experience in New York and San Francisco. He played key roles as an early engineer at GitHub and as CTO of OMG Network, the first production Ethereum Layer-2 network. At the intersection of tech and Thai culture, he currently leads the Typhoon project, a series of open source large language models optimized for Thai. Recognizing the potential of generative AI and large language models, Kasima sees them as transformative for modern knowledge work and for Thailand.

Organized by Antoine Bosselut, NLP lab
11/10/2024 @ 12:15 room Fribourg, HEIA-FR room, HBL 1 22B.

Quantifying the total energy and emissions impact of telework

Prof. Liam O’Brien, Carleton University

Abstract
Teleworking has been widely perceived as a more sustainable mode of working for knowledge workers compared to the status quo of commuting to centralized offices because of its reduced dependency on transportation and centralized office space. However, the situation is far more complex than would appear on the surface, when the scope is expanded to include home office energy use, the Internet, long-term consumer choices, and other so-called rebound effects. Few studies have quantified home, office, transportation, and communications energy or GHG emissions implications of teleworking simultaneously.

This talk will present the results of five years of research trying to address the question: does telework save energy? The methods are broad, spanning surveys, modelling and simulation, and measurement. Based on the results, Prof. O’Brien and his team are currently advisors to the federal government on teleworking policy and the sustainability implications.

Short bio
Liam O’Brien is a professor for Carleton University’s Building Engineering program and the principal investigator of the Human Building Interaction Lab. The HBI Lab includes a team of over 15 researchers with diverse backgrounds in civil, mechanical, and electrical engineering, architecture, and design, who focus on design and control of energy-efficient buildings, with a specialization in occupant behaviour.

Prof. O’Brien has worked with approximately twenty industry and government partners and raised over $8 million in the past decade. He has authored or co-authored over two hundred peer-reviewed publications and co-edited three books on high-performance buildings and occupant research methods. His graduates are professors and researchers in government laboratories and industry R&D departments. He has a wide network of research collaborations due to leadership positions on three International Energy Agency Tasks and two NSERC Strategic Research Networks.

Prof. O’Brien is currently the Operating Agent for the five-year, 100-researcher International Energy Agency Annex 95, titled “Human-centric buildings for a changing climate”. He is heavily involved in the building design and research community, including serving as Past President of the Canadian Chapter of the International Building Performance Simulation Association and Faculty Advisor for ASHRAE. He has chaired two academic conferences, facilitated educational workshops, and given numerous keynote and plenary talks. He has won several prestigious awards including the Carleton Research Achievement Award, Ontario Building Envelope Council Rising Star Award, the Ontario Early Researcher Award, and the International Building Performance Simulation Association (IBPSA) Outstanding Young Contributor Award.

More information

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
18/10/2024 @ 12:15 room GC B1 10

The nexus between ecohydraulics and the freshwater biodiversity crisis

Dr. Luiz da Silva (ETH Zurich)

Abstract:
Freshwater biodiversity has been in sharp decline at higher rates than the terrestrial biota since 1970. For example, recent estimates account for a decline of -81% in migratory freshwater fish populations between 1970 and 2020. This scenario triggered the discussion of an Emergency Recovery Plan for freshwater biodiversity, which includes 6 priority actions. Ecohydraulics, as a discipline and community of practice, can contribute to supporting and realising the recovery plan. In this seminar, I’ll bring examples of ecohydraulics research that may contribute to some priority actions, particularly those related to reestablishing river connectivity, improving environmental flows and protecting habitats for fish. For instance, the early life stages of fish, particularly, are the most threatened by rapidly changing flow conditions in riverine systems. They may struggle to follow the spatial shift in habitat and discharge conditions caused by peak flows downstream of hydropower dams, impairing their capacity to colonise suitable habitats for growth. Although we understand key environmental triggers and broad patterns of larval and juvenile drift in riverine ecosystems, knowledge of the mechanistic processes leading to larval responses in different hydromorphological conditions remains scant. To bridge that gap, we have developed image-based approaches applied to laboratory and field conditions that allowed us to quantify fine-scale movement and drift responses of fish and other aquatic organisms with high resolution and at multiple time scales. In this presentation, I’ll discuss the results of an innovative image-based fish tracking approach used to assess the fine-scale responses of juvenile trout to hydropeaking in a hydraulic flume and present the Riverine Organism Drift Imager – RODI, a camera system that can significantly advance our capacity to understand drift in riverine ecosystems.

Short bio:
Luiz is a senior researcher at ETH Zurich, Stocker Lab. He has an interdisciplinary background in fish ecology (bachelor and master) and mechanical engineering (PhD). He has about 15 years of experience assessing the impacts of hydropower on fish and developing mitigation solutions on a global scale. His research has focused on the design and assessment of fish passage, turbine entrainment and mortality, hydropeaking and larval drift. Luiz is also a member of the steering committee of the fish passage conference and past president of the International Fisheries Section of the American Fisheries Society.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
08/11/2024 @ 12:15 room GC B1 10

Reliability modeling and forecasting with two-stage stochastic degradation models: bridge reinforced concrete rebar example

Prof. David W. Coit, Rutgers University, USA

Abstract
Stochastic degradation models offer distinct advantages compared to traditional reliability analyses. Many degradation processes occur in two distinct stages or phases. This is not unusual or unexpected because (a) often the design includes protective coverings or coatings that beneficially delay the onset of a degradation process, (b) some physical or chemical processes naturally do not occur until there has been a time-delay of some type, or (c) after progressing gradually for some time, a degradation process may become more aggressive and fundamentally change.

There have already been several useful two-stage degradation models in the literature including the gamma-gamma and Weiner-Weiner models and others. In this talk, we introduce a new two-stage degradation model called the Weibull-gamma model. The first stage is modeled by a time-to-event distribution, instead of a stochastic process, to more closely resemble the physical behavior of some delayed failure mechanisms, while the second stage is a stochastic process similar to other models. In the new model, both stages are modeled as a function of stress covariates, which can then be used to conduct accelerated testing. The model is demonstrated using an example of a steel rebar used in reinforced concrete to build more reliable bridges. Testing data was collected for three years under accelerated conditions to evaluate the feasibility and reliability of new steel materials exposed to more stressful conditions. While the new model to useful to predict reliability, it is not particularly useful to forecast future degradation. In the final part of the talk, various machine learning forecasting methods are discussed and demonstrated.

Short bio
David Coit is a Professor in the Department of Industrial & Systems Engineering at Rutgers University, Piscataway, NJ, USA. He has also had visiting professor positions at CentraleSupelec Université Paris-Saclay, Paris, France, Tsinghua University, Beijing, China, and others. His current teaching and research involves system reliability modeling and optimization, and energy systems optimization. He has over 140 published journal papers and over 100 peer-reviewed conference papers (h-index 65). He is currently an Associate Editor for IEEE Transactions on Reliability and Journal of Risk and Reliability and for 15 years was a Department Editor for IISE Transactions. He has been a special issue editor for IISE Transactions, Reliability Engineering & System Safety (RESS) and Computers & Industrial Engineering. His research has been funded by USA National Science Foundation (NSF), U.S. Army, U.S. Navy, industry, and power utilities. His NSF grants included a CAREER grant to develop new reliability optimization algorithms considering uncertainty. He was also the recipient of the P. K. McElroy award, Alain O. Plait award and William A. J. Golomski award for best papers and tutorials at the Reliability and Maintainability Symposium (RAMS). Prof. Coit received a BS degree in mechanical engineering from Cornell University, an MBA from Rensselaer Polytechnic Institute (RPI), and MS and PhD in industrial engineering from the University of Pittsburgh. He is a fellow of Institute of Industrial & Systems Engineers (IISE).

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
05/12/2024 @ 09:30 room

Smart Publishing

EPFL Library

Publishing to make your research available to the scientific community is a rewarding step. Do you want to understand how it works and know some tips that will help at the submission stage?

In this workshop, which will be held on Zoom only, we will address the publication process in the current context:
• Become familiar with the context of scholarly communication and its latest developments
• Understand the important steps leading to publication, including peer-review
• Ensure your compliance towards EPFL and funders' Open Access policy
• Know and protect your rights as an author according to EPFL’s policy
• Get to understand what a publishing contract entails.

Organized by EPFL Library
06/12/2024 @ 12:15 room GC B1 10

Intervenir dans un réseau en exploitation

Amélie Rieder & Stéphane Meylan, bureau Emch + Berger, Bern

Résumé
Les exigences imposées au réseau d’infrastructure respectivement aux ouvrages d’art qui le composent illustrent les multiples besoins actuels de la société : fonctionnalité, viabilité, architecture, efficience tant du point de vue économique que de l’utilisation des ressources, intégration, durabilité, délais de construction, maintenance… Ces exigences grandissantes reflètent une dépendance croissante de la société vis à vis de la fonctionnalité du réseau d’infrastructure et des ouvrages qui le constituent. Dès lors comment intervenir dans ce réseau toujours plus utilisé et qui s’inscrit dans un environnement bâti/aménagé de plus en plus dense ? Comment concilier tous ses besoins ? Amélie Rieder et Stéphane Meylan présenteront quelques réalisations et projets en cours qui permettrons de mettre en évidence les défis auxquels doivent répondre les ouvrages d’aujourd’hui.

CV
Amélie Rieder obtient son master d’ingénieure civile à l’EPFL en 2015. Dans le cadre du cycle Bachelor, elle fait un échange académique à l’Université Polytechnique de Madrid. A la suite de son diplôme, elle travaille chez Emch+Berger à Berne dans le département des ouvrages d’art. En parallèle, elle reste engagée de manière ponctuelle à l’EPFL en tant qu’assistante de construction dans le domaine de la réhabilitation d’ouvrage d’art, dans l’institut du Prof. Dr. Eugen Brühwiler (2017). Au sein du département d’ouvrage d’art de Emch+Berger, elle est depuis 2020 responsable technique dans le domaine ferroviaire puis devient en 2023 responsable adjointe du département.

Stéphane Meylan commence ses études d’ingénieur à l’HEPIA à Genève où il obtient son diplôme d’ingénieur en 2011. Il poursuit ses études à l’EPFL et obtient son master en ingénierie civile en 2015. La même année, il commence à travailler dans le bureau d’ingénierie Structurame à Genève. En 2019, il part travailler une année dans le bureau Afro-European Engineers à Addis Abeba en Ethiopie. En 2020, il rejoint le département des ouvrages d’art chez Emch+Berger à Berne où il est depuis 2024 responsable technique de la construction de ponts. Il s’implique dans les hautes écoles spécialisées et l’EPFL en tant qu’intervenant externe, notamment en 2024, dans le cadre du cours de « Conception et équipements des ponts » des professeurs Alain Nussbaumer et Olivier Burdet.

Des sandwiches sont offerts à la fin du séminaire.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
12/12/2024 @ 16:15 room MED 1 1518

MEchanics GAthering -MEGA- Seminar: [Workshop + Apéro] Best practices in data management: organization, storage & sharing

Christopher Tremblay, Alain Borel

Abstract: This workshop provides a short introduction to research data management (RDM), covering the essential practices to organize, safeguard, and share your data. We will first discuss the differences between storage, backup, and archiving, highlighting EPFL’s solutions to host your projects, prevent data loss and ensure long-term data preservation. We will explore the possible ways to document your data and code effectively for improved reproducibility and collaboration, including metadata, file organization, naming conventions, and others. Finally, we will address data and code publication in agreement with the FAIR principles. We will examine data repositories, the current standard platforms for this purpose, with a focus on CERN’s Zenodo - the most frequent choice at EPFL. We will discuss some legal aspects of data and code publications, i.e. personal data protection and intellectual property.
Join us to enhance your data management skills and get tips that will help you maximize the impact of your research data.

Bio: Christopher Tremblay obtained his master’s degree in life sciences at EPFL. After graduation, he worked for a start-up before moving back to EPFL as a member of the SV-IT team, notably supporting the SLIMS laboratory information system. In November 2024, he has joined the Research Data Management team at EPFL Library.
Alain Borel obtained a diploma and a PhD in chemistry at the University of Lausanne, followed by post-doctoral jobs at the University of Illinois and EPFL. He became head of the chemistry library before the merger of all EPFL libraries into the Rolex Learning Center. In the united EPFL Library, he has been a subject librarian for chemistry and materials science, an IT specialist, and since 2019 he has become part of the Research Data Management team.

The workshop will be followed by our end of the year apéro!

Organized by MEGA.Seminar Organizing Committee
16/12/2024 @ 14:00 room BC 420

AI Center - Research Seminar Series - Edouard Grave

Edouard Grave, Nicolas Flammarion

The talk is preceded by a coffee session, at 13:15 in the adjacent space (BC 430).

For on-site logistics, please use the following form to register: registration form.

Title
Moshi: a foundation model for conversational speech

Abstract
In this talk, I will present Moshi, a joint speech-text foundation model and full-duplex spoken dialogue system. Current systems for spoken dialogue rely on pipelines of independent components, namely voice activity detection, speech recognition, textual dialogue and text-to-speech. Such frameworks cannot emulate the experience of real conversations. First, their complexity induces a latency of several seconds between interactions. Second, text being the intermediate modality for dialogue, non-linguistic information that modifies meaning—such as emotion or non-speech sounds—is lost in the interaction. Finally, they rely on a segmentation into speaker turns, which does not take into account overlapping speech, interruptions and interjections.

Moshi solves these independent issues altogether by casting spoken dialogue as speech-to-speech generation. Starting from a text language model, Moshi generates speech as tokens from the quantizer of a neural audio codec, and separately models its own speech and that of the user into parallel streams. This allows for the removal of explicit speaker turns, and the modeling of arbitrary conversational dynamics. We extend the hierarchical semantic-to-acoustic token generation of previous work, by predicting time-aligned text tokens as a prefix to audio tokens. Our resulting model is the first real-time full-duplex spoken large language model, with a latency of around 200 ms in practice.

Bio
Edouard Grave is a researcher and a member of the founding team at Kyutai, where he works on artificial intelligence, natural language processing and large language models (LLMs). Before joining Kyutai, he spent eight years in industry, first at Facebook AI Research and then at Apple MLR. Edouard also completed a postdoc at Columbia University, where he worked with Noémie Elhadad and Chris Wiggins, and at UC Berkeley, where he worked with Laurent El Ghaoui. He received his PhD in computer science from Université Paris VI and graduated from École Polytechnique with a M.Sc. in machine learning and computer vision.

Hosting professor: Prof. Nicolas Flammarion

Organized by EPFL AI Center
11/02/2025 @ 10:00 room GC B1 10

Air Transportation Systems Research at the University of Michigan

Prof. Max Li

Abstract
The Laboratory for Air Transportation, Infrastructure, and Connected Environments (LATTICE), situated in the Department of Aerospace Engineering at the University of Michigan, Ann Arbor, is focused on identifying and addressing research problems that contribute towards a safer, more efficient, more resilient, as well as user- and equity-oriented air transportation system and other societal-scale infrastructures.

In this presentation, Prof. Max Li will cover some ongoing and recently completed projects at LATTICE, spanning methods such as stochastic/robust optimization, bandit (exploration/exploitation) strategies, combinatorial programs (e.g., facility location problems, vehicle routing problems), reinforcement learning, and probabilistic privacy, applied to a variety of settings ranging from air traffic management, UAS traffic management, and space systems/infrastructures. The overarching goal of his presentation is to solicit feedback and spur discussions, potentially leading to new and exciting interdisciplinary and international collaborations.

Short bio
Max Li is an Assistant Professor of Aerospace Engineering at the University of Michigan, Ann Arbor. He also has courtesy appointments in Civil and Environmental Engineering as well as Industrial and Operations Engineering. Prof. Li received his PhD in Aerospace Engineering from the Massachusetts Institute of Technology in 2021. He earned his MSE in Systems Engineering and BSE in Electrical Engineering and Mathematics, both from the University of Pennsylvania, in 2018. Max’s research and teaching interests include air transportation systems, airport and airline operations, Advanced Air Mobility, networked systems, as well as optimization and control.
25/02/2025 @ 12:00 room MED 0 1418

MechE Colloquium: Nanophotonic Control of Light-energy Conversion Processes

Prof. Giulia Tagliabue, Laboratory of Nanoscience for Energy Technologies (LNET), Institute of Mechanical Engineering (IGM), School of Engineering (STI), EPFL

Abstract: By coupling free-space light to nanoscale dimensions, nanophotonics enables the precise delivery of light energy to nanoscale interfaces, revealing unexpected non-equilibrium phenomena and unlocking novel energy conversion pathways. The interaction of light with nanoconfined solids and liquids thus opens exciting opportunities for transformative advances in energy generation, storage, and strategies to reduce energy consumption. In this talk, I will share our research journey at the intersection of nanophotonics and energy, with a focus on clarifying and controlling photothermal, photochemical, and electrokinetic processes in nanomaterials and at nanoscale solid/liquid interfaces. Specifically, I will present key advances in understanding non-equilibrium charge carrier transfer at metal/molecule interfaces towards light-driven control of chemical reactions. I will also introduce water-based solutions for energy generation and discuss the potential of thermonanophotonic design strategies for energy and optical systems. To conclude, I will offer a perspective on the future of nanophotonics in driving sustainable technologies for energy generation, storage, and efficiency.

Biography: Dr. Giulia Tagliabue is a Tenure-track Assistant Professor in the Department of Mechanical Engineering at EPFL. She joined the Engineering faculty in January 2019 and she is the head of the Laboratory of Nanoscience for Energy Technologies (LNET). She obtained her PhD in Mechanical Engineering from ETH Zurich in 2015. From 2015 to 2018 she was a Swiss National Science Foundation Fellow and she carried on her postdoctoral research jointly at Caltech and the Joint Center for Artificial Photosynthesis (JCAP). Dr. Tagliabue is the recipient of the First Prize of the Rising Stars of Light Award 2020, the 2021 Early Career Award in Nanophotonics, the 2023 Zellner Prize in Physical Chemistry, the 2024 Daniela Pucci Prize in Nanophotonics and the 2024 Latsis University Prize EPFL. Her teaching excellence was also recognized with the 2024 EPFL Best Teaching Award. In 2020 she was awarded an Eccellenza Grant from SNSF and in 2022 she received an SNSF Starting Grant. She is member of ACS, Optica and SPIE. Dr. Tagliabue is currently Managing Editor of the journal Nanophotonics (DeGruyter).

Organized by Institute of Mechanical Engineering (IGM)
25/02/2025 @ 12:15 room

Microplastic Hydrodynamics: Insights from Laboratory Modeling and In-Situ Sampling

Shooka Karimpour

Abstract
Microplastics, plastic debris smaller than 5 mm, have become ubiquitous in aquatic systems, appearing in both freshwater and marine systems, from densely populated regions to deep sea sediments and the Arctic. While there are numerous efforts across the globe on MP detection in various aquatic matrices, these efforts remain resource-intensive and often lack standardization. These challenges, combined with the complexity of regional and global sampling, make MP quantification highly uncertain. Although the presence of MP contaminants in water and sediment is governed by complex physical (and biochemical) processes, many sampling and detection efforts overlook these dynamics. Formulating these processes is highly beneficial for understanding the presence and fate of MPs but also challenging due to the variability in MP characteristics, including shape, size, and density.

This presentation will explore the competing physical mechanisms driving MP transport in aquatic systems, drawing on analogies with sediment transport. We will discuss our findings on the motion of MP particles and their interactions with the surrounding fluid across multiple scales—particle-scale, near-field, and far-field. Insights from laboratory experiments, high-fidelity computational modeling (including Large Eddy Simulation and Direct Numerical Simulation), and in-situ sampling will be presented. In collaboration with Canadian environmental agencies, these findings are informing the development of standardized modeling and sampling frameworks to enhance MP detection and prediction.

Short bio
Dr. Shooka Karimpour is an Associate Professor in the Department of Civil Engineering at York University, Toronto. She earned her Ph.D. in Environmental Fluid Dynamics from McGill University in 2015. Her expertise lies in developing and applying hydro-environmental models to investigate mixing, transport, and entrainment in multiphase flows. Her current research focuses on turbulence-induced transport of sediments and contaminants, in collaboration with Environment and Climate Change Canada and the Ministry of the Environment, Conservation, and Parks. Her work has been published in leading journals such as Journal of Fluid Mechanics, and she has received national and international recognition, including the Best CSCE Hydrotechnical Paper Award (2018) and York University’s Research Award (2022).

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
28/02/2025 @ 12:15 room GC B1 10

Advanced Computational Tools for the Analysis and Design of Complex Metamaterials and Structures

Alejandro M. Aragon

Abstract
The traditional design approach has predominantly relied on trial and error. However, this intuitive approach is not only expensive but also time-consuming, thereby significantly limiting the design process for technological applications. A more effective approach is to adopt a systematic design procedure, for which computational tools have proven to be effective. These tools must not only accurately represent faithfully the physics of the problem but also efficiently discretize and solve (potentially coupled) partial differential equations within an iterative optimization process. Artificial intelligence also holds immense potential for design. However, despite significant advancements in language processing, voice/image recognition, and signal processing, the application of machine learning (ML) in computational design remains in its nascent stages. Therefore, harnessing innovations in ML- based models and integrating them with precise physics-based modeling is the key to novel groundbreaking design methodologies.

This presentation will discuss current developments on novel physics-based and machine learning-driven models for the analysis and design of metamaterials and structures. We will first discuss advancements in enriched finite element methods (e-FEMs), which augment standard finite element analysis by incorporating in- formation about discontinuities by means of enrichment functions. These sophisticated methods completely decouple finite element meshes from the geometry of the problem, facilitating fully automated and accurate analysis. Over the years, we have developed e-FEMs to address a wide range of intricate problems in solid mechanics, including the modeling of weak discontinuities (e.g., perfectly-bonded material interfaces) and strong discontinuities (fracture). Additionally, we have extended their application to immersed boundary (or fictitious domain) problems and to tie numerical interfaces (mesh coupling) and to solve highly-nonlinear contact problems. Beyond analysis, e-FEMs have proven valuable in computational design through the application of enriched topology optimization (e-TO). We demonstrate the application of e-TO in mitigating the likelihood of fracture in brittle solids designing chocolate edible unit cells with extreme fracture anisotropy and maximizing band gaps in phononic crystals and photonic devices. Finally, we present some developments in the domain of machine learning. Specifically, we discuss recent advancements in neural reparameterization, wherein we employ a neural network as a generative design technique completely alternative to topology optimization.

Short bio
Dr. Aragon is currently Associate Professor in Computational Design and Mechanics in the Mechanical Engineering faculty of Delft University of Technol- ogy. He holds a BSc degree from Argentina, and both an MSc (as a Fulbright Scholar) and PhD degrees from the University of Illinois at Urbana-Champaign (UIUC), USA. Dr. Aragon held postdoctoral roles at UIUC and at EPFL.

He has more than 15 years of experience developing pioneering computational techniques for analysis and design in solid mechanics. His research focuses on developing enriched finite element and topology optimization technology to address design challenges across biomimetic and composite mate- rials, acoustic/elastic metamaterials, photonic and phononic crystals, edible metamaterials, and origami. He holds two patents in noise attenuation applications using acoustic/elastic metamaterials and phononic crystals. He is the lead author of the book “Fundamentals of Enriched Finite Element Methods” (Elsevier, 2023). Finally, he is director of the Machine Intelligence Advances for Materials (MACHINA) lab, which integrates machine learning into computational design.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
07/03/2025 @ 12:15 room GC B3 31

Optimization-based rigid block models for historical masonry structures: from limit analysis to nonlinear dynamics

Francesco Portioli

Abstract
The talk presents an overview of the research activities carried out at the University of Naples in the last decade which were aimed at developing rigid block models and software tools for the analysis of historical masonry structures. In the proposed models, masonry is schematized as an assemblage of rigid blocks interacting at interfaces, for which a no-tension frictional behavior is generally assumed. Vertical and lateral loads as well as support movements are considered. Moving from rigid block models developed for limit analysis, the seminar illustrates the research path and the main concepts which inspired the development of a unified approach to rigid block modeling. The approach relies on an optimization-based formulation for nonlinear time-history analysis which is equivalent to the system of equations governing the behavior of rigid block assemblages and comprises as special cases formulations for nonlinear static and limit analysis. In order to capture the behavior of masonry with high-strength mortar joints, recent extensions of the formulations previously developed for nonlinear static analysis with no-tension interfaces to elasto-plastic cohesive interfaces with damage behavior are illustrated. The main functionalities and organization of the software tools developed on the basis of the proposed formulations for limit analysis as well as for nonlinear static and time-history analysis are also presented. Finally, applications to numerical and experimental tests from literature and to full-scale case studies are illustrated to show potentialities and computational efficiency of the developed models.

Short bio
Dr. Francesco P.A. Portioli is an Associate Professor of Structural Engineering at the University of Naples Federico II since October 2018. He received his PhD by the University of Chieti Pescara “G. D’Annunzio” in 2004, discussing a thesis on the structural behavior of masonry vaults strengthened with FRP. He served as Postdoctoral Researcher and was Assistant Professor at the University of Naples from 2004 until 2018. He is a lecturer in undergraduate and postgraduate courses at the Department of Architecture and at the School of Specialization in Architectural Heritage and Landscape in Naples. His main research interests include safety assessment methods and modeling approaches for historical masonry structures and steel structures. He is author of several papers on international journals and conference articles. He is also the author of book chapters of national and international books, dealing with life-time structural engineering and seismic retrofitting of historical masonry structures.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
14/03/2025 @ 12:15 room GC B1 10

Synthetic Lightweight Aggregates: Engineered Solution for Sustainable Material Management

Chris Swan

Abstract
This presentation focuses on 1) a fundamental understanding of the physical and mechanical behaviors of a synthetic construction aggregate and 2) other factors (economic, social, and political/regulatory; at multiple geographical scales) involved in realizing the product as an appropriate waste reuse strategy.

Background: In any industrial ecosystem, waste is inevitable. However, the most efficient and sustainable industrial systems strategize ways to optimize their various interacting components to reduce waste via waste reuse strategies. Synthetic lightweight aggregates (SLAs) represent a waste reuse strategy for two large volume waste streams: coal fly ash and mixed thermoplastic wastes. Previous work has evaluated SLAs as a ‘green’ construction material that can also provide unique benefits to the health and sustainability of various infrastructure components. For example, current work has focused on SLAs as an energy-absorptive geo-material with the potential to help infrastructure components weather the impacts of dynamic loadings such as earthquakes and explosions. Additionally, this engineered material provides a clear environmental value in reducing the leaching of contaminants commonly found in coal fly ashes. As such, the SLA technology has been technically shown to be a potentially significant benefit that can enhance an industrial ecosystem and its infrastructure development.

Short bio
Chris Swan is a professor in the Civil and Environmental Engineering (CEE) department in the School of Engineering at Tufts University. He also serves as an Associate Dean for Inclusive Excellence (ADIE), representing the school on Tufts University Cabinet on Institutional Inclusive Excellence. This latter title was borne from his own education research on diversifying the audience for STEM education through various pedagogical approaches, including service-learning and entrepreneurship. Additionally, he has a faculty appointment as a professor in the Tisch College of Civic Life and is a fellow in the Center for Engineering Education and Outreach. Previously, he has served as the Dean of Undergraduate Education (2018-2024), the Associate Dean of Undergraduate Curriculum Development (2012-2015) and as CEE department chair (2002-2007) in the school. He has also served as an Associate Dean of Tisch College (2016). He received a Doctor of Science (ScD) degree in Civil and Environmental Engineering from MIT and both his Bachelor (BS) and Master (MS) of Science degrees in Civil Engineering from the University of Texas at Austin. Prior to pursuing his ScD, he worked for GZA Geoenvironmental, Inc. as a staff engineer (1986-1989).

Over is 30+ years in academia, he has researched the development/implementation of reuse strategies for waste materials. Most notably, his research efforts have focused on the reuse of fly ash from coal burning facilities mechanically combined with waste plastics. Additionally, he has engaged in research on the teaching and learning in engineering. Specifically, these efforts have focused on a) evaluating the impact of service-based learning in engineering education, b) applying entrepreneurial principles in examining sustainable and scalable pathways for innovations in engineering and engineering education, and c) evaluating faculty perspectives on the inclusion of macroethics in engineering education.

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
21/03/2025 @ 12:15 room GC B1 10

Nonsmooth dynamics of extrinsic cohesive models for fracture

Vincent Acary

Abstract
Cohesive zone models are an effective tool for simulating fracture in solids. They are generally differentiated between intrinsic models, which have an elasticity of their own at the interface, and extrinsic models, which behave as rigid interfaces prior to the initiation of fracture. The main problems with intrinsic models are as follows: they substantially modify the global elasticity of the materials, the interface elasticity is difficult to measure experimentally and they lead to stiff numerical systems involving strong constraints on the choice of time–integration schemes and the size of time steps.

In this work [1,2], we propose an extrinsic cohesive zone model that contains one-sided contact and Coulomb dry friction as residual behaviour at fracture. In order to model an extrinsic model, it is necessary to be able to write set-valued non-smooth models, i.e. models that take a set of possible values for a given displacement of the interface. What is fairly standard for unilateral contact and friction is therefore extended to the cohesive part with damage using the tools of convex and variational analysis.

In the spirit of M. Frémond’s work, the model is written from thermodynamic principles in order to guarantee energy consistency. A time integration scheme for the dynamics preserves its properties in discrete time. The discrete system solved at each time step is a well-posed linear complementarity problem, guaranteeing the existence of solutions and uniqueness in the frictionless case where it is just a convex quadratic program.

We will end this presentation by emphasising the fact that this framework, which makes it possible to model softening behaviour using non-convex interface energies, leads to well-posed convex or co-positive models. This is mainly due to the presence of inertia, which enables the problem to be well defined and solved efficiently.

[1] Nicholas Anton Collins-Craft, Franck Bourrier, Vincent Acary. On the formulation and implementation of extrinsic cohesive zone models with contact. Computer Methods in Applied Mechanics and Engineering, 2022, 400, pp.115545. 〈10.1016/j.cma.2022.115545〉. 〈hal-03371667v5〉
[2] Nicholas Anton Collins-Craft, Franck Bourrier, Vincent Acary. On the formulation and implementation of mixed mode I and mode II extrinsic cohesive zone models with contact and friction. 2024. 〈hal-04447397〉

Short bio
Vincent Acary is a research director at INRIA, Grenoble-Alpes University Centre. He is head of the TRIPOP team, which specialises in the modelling, analysis, simulation and control of non-smooth dynamical systems. He is particularly interested in the development of numerical methods and simulation codes, in particular for unilateral contact with friction, plasticity, impacts and fracture mechanics. The most important application of this work in recent years has been in the field of natural gravity hazards in mountainous areas. More details at https://tripop.inrialpes.fr/people/acary/

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)
28/03/2025 @ 12:15 room GR A3 30

Microplastic Hydrodynamics: Insights from Laboratory Modeling and In-Situ Sampling

Shooka Karimpour

Abstract
Microplastics, plastic debris smaller than 5 mm, have become ubiquitous in aquatic systems, appearing in both freshwater and marine systems, from densely populated regions to deep sea sediments and the Arctic. While there are numerous efforts across the globe on MP detection in various aquatic matrices, these efforts remain resource-intensive and often lack standardization. These challenges, combined with the complexity of regional and global sampling, make MP quantification highly uncertain. Although the presence of MP contaminants in water and sediment is governed by complex physical (and biochemical) processes, many sampling and detection efforts overlook these dynamics. Formulating these processes is highly beneficial for understanding the presence and fate of MPs but also challenging due to the variability in MP characteristics, including shape, size, and density.

This presentation will explore the competing physical mechanisms driving MP transport in aquatic systems, drawing on analogies with sediment transport. We will discuss our findings on the motion of MP particles and their interactions with the surrounding fluid across multiple scales—particle-scale, near-field, and far-field. Insights from laboratory experiments, high-fidelity computational modeling (including Large Eddy Simulation and Direct Numerical Simulation), and in-situ sampling will be presented. In collaboration with Canadian environmental agencies, these findings are informing the development of standardized modeling and sampling frameworks to enhance MP detection and prediction.

Short bio
Dr. Shooka Karimpour is an Associate Professor in the Department of Civil Engineering at York University, Toronto. She earned her Ph.D. in Environmental Fluid Dynamics from McGill University in 2015. Her expertise lies in developing and applying hydro-environmental models to investigate mixing, transport, and entrainment in multiphase flows. Her current research focuses on turbulence-induced transport of sediments and contaminants, in collaboration with Environment and Climate Change Canada and the Ministry of the Environment, Conservation, and Parks. Her work has been published in leading journals such as Journal of Fluid Mechanics, and she has received national and international recognition, including the Best CSCE Hydrotechnical Paper Award (2018) and York University’s Research Award (2022).

Sandwiches are offered at the end of the seminar.

Organized by Prof. Olga Fink (IMOS), Prof. Alexandre Alahi (VITA), Prof. Dusan Licina (HOBEL), Prof. Alain Nussbaumer (RESSLab)