The Role of Soil on the Collapse of 18 Piers of the Hanshin Expressway in the Kobe Earthquake

本研究旨在加深对土-结构-相互作用(SSI)对桩基公路桥梁地震反应影响的认识。1995年神户地震期间，高架阪神高速公路的18个桥墩坍塌(以及最近地震中加利福尼亚州和威尔周围的其他桥梁)，这引发了人们对此类结构的地震行为的当前理解以及现有地震法规是否足够的担忧。在韩新高速公路的案例中，对地震和工程信息的初步研究表明，土、桩和上部结构之间的动态相互作用可能是导致大桥坍塌的原因之一。一个由美国和日本工程师参与的合作研究项目正在进行中，以调查SSI在坍塌中的作用。主要目标是：(1)分析坍塌节段的地震反应；(2)对未坍塌的相邻节段重复分析；(3)通过与以前没有考虑SSI影响的研究结果以及根据现有地震规定进行的预测进行比较，对结果进行评估。日本合作者是清水株式会社岩土事业部总经理Takashi Tazoh博士。他正在为现场提供地震学、岩土和结构数据，并使用清水首创的分析技术进行替代分析。研究将纯粹是分析性的，不计划进行任何实验。除了揭示坍塌的原因外，这项研究还将开发对工程人员具有直接价值的实用分析工具。该项目得到了NSF 98-36“美日城市地震减灾合作研究”下的第三年竞赛的支持。

0000101MylonakisThe object of this research is to improve the understanding of the effect of soil-structure-interaction (SSI) on the seismic response of pile-supported highway bridges. The collapse of 18 piers of the elevated Hanshin expressway during the 1995 Kobe earthquake (as well as of other bridges in California and around the would in recent earthquakes) has raised concerns about the current understanding of the seismic behavior of such structures and the adequacy of existing seismic regulations. In the case of Hanshin Expressway, preliminary examination of seismological and engineering information indicates that the dynamic interplay between soil, piles and superstructure may have contributed to the collapse of the bridge.A collaborative research program is being conducted involving a U.S. and a Japanese engineer to investigate the role of SSI on the collapse. The main objectives are: (i) to analyze the seismic response of the collapsed segment; (ii) to repeat the analysis for adjacent segments that did not collapse; (iii) to evaluate the results by comparing with results from earlier studies that did not consider SSI effects, and with predictions based on current seismic provisions. The Japanese collaborator is Dr. Takashi Tazoh, General Manager of the Geotechnical Division at Shimizu Corporation. He is providing seismological, geotechnical, and structural data for the site an is performing alternative analysis using analytical techniques pioneered at Shimizu.The research will be purely analytical; no experiments are planned. Apart from shedding light on the causes of the collapse, the research will develop practical analysis tools which can be of immediate value to engineers.This project is supported under the 3rd - Year Competition under NSF 98-36 "US - Japan Cooperative Research in Urban Earthquake Disaster Mitigation".