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

本研究的目的是提高对土-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，阪神高速公路（Hanshin high - high expressway）的18个高架桥墩倒塌（以及加州和附近地区的其他桥梁在最近的地震中倒塌），引发了人们对目前对此类结构的地震行为的理解以及现有地震法规的充分性的担忧。在阪神高速公路的案例中，对地震和工程信息的初步检查表明，土、桩和上部结构之间的动力相互作用可能是导致桥梁倒塌的原因。一名美国工程师和一名日本工程师正在进行一项合作研究计划，以调查SSI在倒塌中的作用。主要目标是：(1)分析坍塌段的地震反应；（ii）对未坍塌的相邻段重复分析；（iii）通过与未考虑SSI影响的早期研究结果和基于当前地震规定的预测结果进行比较，来评估结果。日本合作者是清水公司岩土工程部总经理Takashi Tazoh博士。他为现场提供地震、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。这项研究将纯粹是分析性的；没有实验计划。除了揭示倒塌的原因外，这项研究还将开发实用的分析工具，对工程师有直接的价值。本项目为国家自然科学基金98-36“美日城市地震减灾合作研究”第三年竞赛项目。

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".