Speaker
Dr. Marios PANAGIOTOU
Assistant Professor, Department of Civil and Environmental Engineering
University of California, Berkeley
Abstract
It is predicted that by 2030, 60% of the world’s total population will live in urban areas (47% in 2000). The number of tall buildings in urban centers and of major bridges near large earthquake faults will increase accordingly. Current seismic design for tall buildings and bridges focuses primarily on collapse prevention and does not attempt to limit damage and ensure post-earthquake functionality. Such design philosophy may result in unprecedented economic and social losses, following a major earthquake, which are inappropriate for the needs of many urban regions of the early and mid XXI century. For shallow earthquakes, regions in the direction and within 10 km from the fault rupture are usually subjected to the most severe near-fault ground motions (NFGMs) that contain strong pulses. For example, after the 2011 magnitude 6.3 (M6.3) earthquake in New Zealand (5 km from the fault), 36 out of the 50 tallest buildings in Christchurch were demolished, causing major disruption of the city center operation for over two years.
This presentation addresses the question: Can we economically design tall (up to 20 stories) buildings and bridges in near-fault regions that sustain minimal damage and remain functional after major (up to M8) shallow earthquakes? Presented first are recent research findings on the presence of multiple strong pulses in individual historical NFGMs and the implications for structural response. The second part of the presentation focuses on the analytical development of earthquake-resilient designs for 20-story tall reinforced concrete (RC) buildings using large seismic isolation devices and rocking core walls. As demonstrated, using response history analysis, these designs experience minimal damage and ensure prompt postearthquake functionality. A comparison to conventional code-compliant 20-story RC wall buildings is shown. A three-dimensional beam-truss modeling approach for RC non-planar wall buildings that accounts for flexure-shear interaction is presented. Next, the analytical and experimental development of earthquake-resilient RC bridges that use rocking columns or combination of rocking foundations and seismic isolation devices is discussed. The presentation concludes with the results of a large-scale shake table test of bridge columns supported on rocking foundations including physical modeling of the soil.
Biography
Marios Panagiotou received his Ph.D. from University of California (UC) San Diego in 2008, where he was responsible for the seismic design, analysis, and shaketable testing of a full-scale 7-story RC wall building slice [Fig. (d)], the tallest structure ever tested on a shake table in United States. He was awarded the 2012 Alfred Noble Prize bestowed by the American Society of Civil Engineers for his journal paper related to the 7-story building slice project. Currently, he is an Assistant Professor in the Civil and Environmental Engineering Department of UC Berkeley. His research efforts include the analytical and experimental development of earthquake-resilient structures, computational modeling of RC structures subjected to earthquake loading, dynamic soil-structure interaction, and engineering characterization of earthquake ground motions.