Evolution of seismic building design practice in Japan

Abstract

The widespread destruction of the built environment in the Kobe region as a result of the 1995 Hyogo-ken Nanbu earthquake was unexpected by many design professionals, academicians and researchers, both in Japan and the United States. Questions raised in the aftermath of the earthquake include: ‘What happened?’, ‘Why did it happen?’ and ‘What are the implications of the observed damage for seismic design practice in the U.S.—especially those regions of high seismic hazard?’ The goals of this paper are three-fold, namely: (a) to trace the development of design and construction practices in Japan so that the observed damage can be better understood; (b) to briefly to compare seismic design practice in regions of high seismicity in Japan and the U.S. at the time of the Hyogo-ken Nanbu earthquake; and (c) to assess the implications of this devastating earthquake on design practice in the U.S. Construction practice in Japan and the U.S. differs substantially. As such, it is difficult to make direct comparisons between design practice in the two countries. However, simple comparisons between current seismic codes in Japan and the U.S. suggest that Japanese buildings are likely to be stronger and stiffer than similar buildings in the U.S. The implication of the behavior of older buildings in Kobe during the Hyogoken-Nanbu earthquake is that severe damage to similar constructions in the U.S. must be expected in a design earthquake. Further, unexpected severe damage and collapse of modern construction in Kobe suggest that modern­construction on the West Coast of the U.S. would be likely to suffer damage in a severe earthquake. © 1998 John Wiley & Sons, Ltd.