CEE Seminar: Twenty-Two Years after Kobe & Six Years after Tohoku - A Japanese Way toward Earthquake Disaster Mitigation
President, Kobori Research Complex (KRC)
Counselor, Kajima Corp.
Professor Emeritus, Kyoto University, Japan
Reception: 12:00PM to 1:00PM
Seminar: 1:00PM to 2:00PM
Abstract: The devastating 1995 Kobe earthquake revealed a landscape of collapsed structures, showing that our cities were vulnerable with many existing structures that were built under outdated design and construction practices. Various efforts in both the public and private sectors were implemented after the earthquake to upgrade our old infrastructures and buildings as well as to make our construction technologies more advanced for the creation of stronger and more durable societies. A notable effort along this line was the construction and operation of a very large shaking table nicknamed E-Defense. The presenter served as the inaugurating director of E-Defense and supervised over 40 full-scale or large-scale tests. A few representative tests are introduced, together with the backgrounds of those tests as well as the difficulties associated with large-scale testing. Sixteen years have passed since the 1995 Kobe earthquake; then Japan was severely hit again by a huge tsunami and earthquake named the 2011 Tohoku earthquake. Thanks to the advancement of seismic design and construction, performance of buildings and infrastructural systems was generally satisfactory, but a huge rupture of faults generated an unprecedented tsunami disaster. The damage extended into a huge region and also caused a new problem regarding overall recovery of the society. The word, resilience, has become a norm to overcome the Tohoku damage to prepare for the future. Among various efforts to this end, a national project that deals with quantification of “collapse margin” was conducted, in which the presenter served as the principal investigator. The project included collapse tests of a steel high-rise office building and an RC mid-rise apartment building. The tests also looked into the effectiveness of structural health monitoring in terms of the identification of damage location and severity. The outline and major results of the tests are summarized, and major findings are presented particularly in light of the importance of quantification of collapse margin before the earthquake and prompt assessment of damage immediately after the earthquake. In line with various research efforts, practice has also been promoted to realize more resilient societies throughout Japan. A few examples of recent very large-scale retrofit and renovation will also be touched upon.
Bio: Masayoshi Nakashima is a professor emeritus at Kyoto University, Japan. He earned bachelor's and master's degrees from Kyoto University and his doctorate from Lehigh University in Pennsylvania. After graduating, he started working for the Building Research Institute (BRI) of Japan and then for Kobe University before joining Disaster Prevention Research Institute (DPRI), Kyoto University. His fields of research include seismic analysis and design of steel building structures and large-scale experimental techniques for the simulation of earthquake responses. Nakashima and his students have published about 400 technical papers, nearly 200 of them appearing in archived journals. He has earned various national and international awards, including the Best Paper Prize of AIJ (Architectural Institute of Japan), the Best Paper Prize of JSSC (Japanese Society for Steel Construction), the ASCE (American Society of Civil Engineers) Moisseiff Award (2000), the 2009 Special Achievement Award of AISC (American Institute for Steel Construction), the ASCE Ernest E. Howard Award (2013), and the 2014 EERI (Earthquake Engineering Research Institute) George W. Housner Medal, among others. He is member of the Engineering Academy of Japan and also an inducted foreign member of the National Academy of Engineering of the United States. Currently, Nakashima serves as president of the Architectural Institute of Japan and president-elect of the International Association for Earthquake Engineering. He also serves as editor of the International Journal of Earthquake Engineering and Structural Dynamics (EESD). He serves as president of Kobori Research Complex (KRC) and as counselor of Kajima Corporation. KRC is a research institution in close collaboration with Kajima.