Direct Displacement-Based Seismic Design

Transcription

1 University of Pavia Short Course on Direct Displacement-Based Seismic Design Pavia, Italy, May 7-11, 2018 Gpsdf H f F m e rk i h e M k M ghh { f Ejtqmbdfnfou (a) SDOF representation (b) Effective Stiffness, K eff Equivalent Viscous Damping Elasto-Plastic RC Frame RC Bridge Displacement Ductility (c) Equivalent Viscous Damping Spectral Displacement (m) =5% =17% f 0.1 V 0 ghh Period (s) (d) Displacement Spectrum

2 Background In 1993, M.J.N. Priestley published a ground-breaking paper on Myths and Fallacies in Earthquake Engineering, highlighting a number of fundamental shortcomings associated with force-based design methods. To provide engineers with a better alternative to FBD, Priestley and co-workers proposed the Direct displacement-based design (DBD) method and over the decades that followed it has been developed for a range of structural systems. Many of the developments made have been summarized in a text on the subject of Direct DBD, published in 2007 (Displacement-Based Seismic Design of Structures by Priestley, Calvi and Kowalsky, IUSS Press, 2007), which will be referred to during this course. The relevance and originality of the Direct Displacement Based Design method is best expressed by the incipit of a review by Graham Powell (Emeritus Professor at UC Berkeley): It is rare for a book on structural engineering design to be revolutionary. I believe that this is such a book. If you are involved in any way with seismic resistant structural design, this should be on your bookshelf, and you should read at least the first three chapters. Objectives of the course The course presents the fundamentals and application of Direct DBD for a range of structures, with consideration also given to the subject of displacement-based seismic assessment and retrofit. Design cases will be presented to allow the participants to try some application on their own. At the end of the course, students should be able to: Understand the fundamental concepts of the Direct DBD method. Undertake Direct DBD for a range of structural systems and types. Describe analysis methods that could be used to verify the results of a Direct DBD solution. Understand the displacement-based seismic assessment and retrofit process. The course will be illustrated by five sets of exercise labs requiring displacement-based seismic design of a variety of structures. In some cases the designs will need to be verified by inelastic time-history analyses, using programs provided as part of the text book. This will be demonstrated in class, during the exercise labs. A strong structures background is a prerequisite for the course, as is at least a basic understanding of conventional seismic design procedures.

3 About the Instructors Gian Michele Calvi is Professor and Director of the Centre for Research and Graduate Studies in Understanding and Managing Extremes (UME) at the University Institute for Advanced Studied (IUSS), Pavia. He is also Adjunct Professor at the North Carolina State University. He received a Master of Science from the University of California, Berkeley, a PhD from the Politecnico di Milano and a Honorary Doctorate from the University of Cujo, Mendoza, Argentina. Professor Calvi has been the founder of the Eucentre Foundation and founder and director of the School in Reduction of Seismic Risk (the ROSE School), which originated the UME School; he is one of the Directors of the International Association of Earthquake Engineering. He is author of more than 300 publications and of two major books: Seismic design and retrofit of bridges (with M.J.N. Priestley and F. Seible, 1996) and Displacement-Based Seismic Design of Structures (with M.J.N. Priestley and M.J. Kowalsky, 2007). He has been designer, consultant or checker for hundreds of structural projects, among which the Rion-Antirion cable stayed bridge (2883 m, in Greece), the Bolu viaduct (119 spans, in Turkey) and the new housing system after L Aquila earthquake (2009), with 185 buildings seismically isolated with more than 7,000 devices, completed in about six months. He has been invited keynote speakers in tens of conferences, including two World and three European Conferences on Earthquake Engineering. Tim Sullivan is Associate Professor at the University of Canterbury, New Zealand. He obtained a 1st Class Hon.s Degree in Civil Engineering from the University of Canterbury, New Zealand and received his Masters and PhD in Earthquake Engineering from the ROSE School, University of Pavia, Italy. He is author of more than 100 publications in the field of earthquake engineering, with many on the subject of displacement-based seismic design. He is also leader of Flagship 4: Next Generation Infrastructure of QuakeCoRE (The New Zealand Centre of Research Excellence (CoRE) for earthquake engineering). He was awarded the 2012 Plinius Medal by the European Geosciences Union in recognition of his interdisciplinary research on seismic hazards, and the 2012 Otto Glogau Award by the New Zealand Society of Earthquake Engineering for best journal paper. He is an invited member to Editorial Boards of various journals, and is an invited faculty member of the ROSE School. He also has considerable consulting experience, having worked in New Zealand, Germany and the UK, and is a chartered engineer with the Institute of Civil Engineers (UK). Dr. Sullivan is particularly well recognized for his work in displacement-based seismic design (DBD) being lead editor of a Model Code for DBD released in 2012.

4 Course Schedule May 7-11, 2018 Monday 7th May Morning Session: An introduction to Direct Displacement-Based Design (Prof. Calvi) Historical development of seismic design methods Concepts of strength, ductility and displacement capacity Problems with Force-Based Design Performance Criteria DDBD of SDOF systems Consideration of Inputs Afternoon Session: DDBD of Cantilever RC wall buildings (Prof. Sullivan) DDBD procedure Exercise Lab 1: DDBD of a multi-storey cantilever wall building Tuesday 8th May Morning Session: DDBD of Frame and Frame-Wall buildings (Prof. Sullivan) DDBD procedure - Displacement profile - Equivalent viscous damping - Accounting for P-delta effects - Accounting for higher modes Afternoon Session: Exercise Lab 2: DDBD of a multi-storey RC building (Prof. Calvi)

5 Wednesday 9th May 09:00-12:00 and 14:00-17:00 Morning Session: DDBD of bridges (Prof. Calvi) DDBD for excitation in bridge longitudinal direction DDBD for excitation in bridge transverse direction Afternoon Session: Methods of verification and Capacity Design (Prof. Sullivan) Non-linear analysis verification options Capacity design considerations Thursady 10th May Morning Session: DDBD of base-isolated buildings (Prof. Calvi) Background and technology DDBD for base-isolated buildings Potential benefits of base-isolation Afternoon Session: Exercise Lab 3: DDBD of a base-isolated building (Prof. Calvi) Friday 11th May Morning Session: Displacement-based seismic assessment and retrofit (Prof. Sullivan) Assessment and retrofit objectives Identification of likely plastic mechanism Identification of displaced shape Conversion from MDOF to equivalent SDOF system Evaluating seismic performance Retrofit options Afternoon Session: Exercise Lab 4: Assessment of an existing RC frame structure (Prof. Sullivan)

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