跨越山谷高墩混凝土桥地震倒塌分析

高墩桥在中国西部多山谷地区得到广泛的应用,然而对其抗震性能的研究并不充分,我国尚没有确立相关的分析设计方法与规范,因此对其进行非线性地震响应分析乃至倒塌分析以便研究其地震破坏模式是十分有意义的。本文以贵州省高速公路上跨越山谷的某大桥为例进行了研究。该桥是一座处于典型西部地区山地、桥体为双向分离的曲线T型刚构高墩混凝土桥。本文在对全桥进行动力特性分析的基础上,采用有限元软件LS-DYNA进行了全桥非线性时程响应分析,考虑桥体的碰撞,得到塑性铰形成与发展状况以及破坏模式,实现了对全桥倒塌过程的仿真。本研究结果对类似桥梁的抗震设计提供了有益的参考。

Analysis of the Collapse of High-pier Bridges Crossing Deep Valleys of Mountain Area under Earthquake

Recently,many high pier RC bridges have been constructed crossing deep valleys at mountain area in western China,where the geotechnical condition is more complicated and the earthquake is more active.However,because the researches on seismic performance of such type of bridges are not sufficient and there is no seismic design specification,so far high pier bridges were designed referring to the seismic design code for ordinary RC bridges.In this study,collapse of a high pier RC bridge crossing deep valley due to strong earthquake was simulated.Based on the modal analysis firstly,the dynamic characteristic of high pier bridge could be gotten.Then nonlinear time-history analysis of bridge considering collision of the two parallel bridge girders was carried out.The process of plastic hinge development of the whole bridge and the damage mechanisms were studied.The methodology and results of the simulation in this paper is expected to be helpful for the seismic design and analysis of high pier RC bridge.