BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:Advanced numerical analysis as a tool for the research and design of unconventional steel structures DTSTART:20161021T121500 DTEND:20161021T131500 DTSTAMP:20260415T011204Z UID:5f971e0d80fc0e19bf820ad9a3bf9a5a68d01adb24f1e03599a1e17a CATEGORIES:Conferences - Seminars DESCRIPTION:Prof. Dr Charis J. Gantes\, Institute of Steel Structures – School of Civil Engineering – National Technical University of Athens\, Greece\nAbstract : Numerical calculation of the ultimate strength of uncon ventional 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 ela stic analyses with corresponding resistances given from formulas that acco unt indirectly for geometric and material nonlinearity as well as imperfec tions. Thus\, prediction of collapse\, which is a strongly nonlinear pheno menon\, is possible by performing linear analyses\, using simple software that is readily available and sufficiently reliable for ordinary structura l systems. Alternatively\, prediction of ultimate strength via nonlinear n umerical analyses is also permitted by modern codes. This method is recomm ended for complex structural systems or members with unusual shapes and ir regular cross-sections\, as such cases are not covered by available buckli ng curves and interaction equations. This can only be accomplished success fully if engineers posses the necessary theoretical background\, so that t hat they can set-up realistic numerical models\, select appropriate soluti on algorithms and parameters and are able to interpret correctly the resul ts.\n\nAlong these lines\, in the first part of the present lecture fundam ental concepts of nonlinear structural behavior will be briefly reviewed. Numerical tools for understanding the behavior\, predicting all possible f ailure modes and evaluating the ultimate capacity of steel structures usin g commercially available software will then be presented. Failure dominate d by either material yielding or instability will be addressed\, as well a s interaction of failure modes. Steps of the proposed methodology include setting up an appropriate finite element model\, obtaining critical buckli ng modes from linearized buckling analysis (LBA)\, and then using a linear combination of these modes as imperfection pattern for a geometrically an d material nonlinear imperfection analysis (GMNIA). Equilibrium paths acco mpanied by snapshots of deformation and stress distribution at characteris tic points will be highlighted as a powerful tool for evaluating the resul ts of the GMNI analysis\, identifying the dominant failure modes and thus proposing appropriate strengthening measures\, if needed. \n\nIn the seco nd part of the presentation applications of this approach in research acti vities will be described\, including (i) strengthening of the manhole at t he 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 b ehavior of large-diameter industrial steel chimneys.\n\nIn the third and f inal part applications of the above approach in actual engineering project s will be briefly mentioned\, including (i) the suspended roof covering th e archaeological site of Aristotle’s Lyceum in Athens\, (ii) the evaluat ion of consequences of potential landslides and fault activation on the bu ried 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 Lima ssol.\n\nBio :\n\nProf. Charis Gantes\, born in Athens\, Greece\, in 1962\ , attended the German High school of Athens (Dörpfeld Gymnasium)\, and th en obtained a Civil Engineering Diploma from the National Technical Univer sity of Athens (NTUA) in 1985\, and a Master’s (1988) and Ph.D. (1991) f rom the Massachusetts Institute of Technology (MIT). Since 1994 he is facu lty member in the Institute of Steel Structures at NTUA\, where he is teac hing steel structures\, structural stability and tension structures.\n\nHi s current research activity is in the area of structural behavior\, analys is and design under extreme loads\, including seismic\, wind and blast\, l eading structures to nonlinear response\, with emphasis on steel structure s. He is author of one book in English\, on deployable structures\, and th ree books in Greek\, on design of unconventional steel structures\, struct ural stability and tension structures. He is also author of 10 book chapte rs\, 81 peer-reviewed journal papers and 150 conference papers. His resear ch work has received more than 950 citations\, excluding self-citations an d citations by co-authors. He is Editor-in-Chief of the Journal of the Int ernational Association for Shell and Spatial Structures (IASS). He is Memb er 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.\n\nIn a ddition\, he is active in structural design and consulting\, having partic ipated in design projects of the steel roofs of three major Greek football stadiums\, structures for the 2004 Athens Olympic Games\, buried pipeline s transporting oil and natural gas\, underground structures including tunn els and stations for the Athens subway\, transmission towers\, guyed tower s\, wind turbine towers\, port\, marine\, energy and industrial facilities projects\, as well as the seismic design of the steel gates for the New P anama Canal. LOCATION:GCA331 http://plan.epfl.ch/?lang=fr&room=GCA331 STATUS:CONFIRMED END:VEVENT END:VCALENDAR