上跨软土深基坑干线铁路便桥动力特性研究

以某铁路大型车站改建工程软土深基坑施工为背景，拟定了多个钢格构柱现浇钢筋混凝土梁板连续刚构便桥设计方案，针对便桥结构体系伴随软土深基坑挖土施工而不断发生变化的特点，系统计算分析了软土深基坑挖土过程便桥结构全桥体系的动力特性，得到一些有益的结论，可供上跨深基坑干线铁路便桥设计和基坑挖土施工参考。

Effect on Seismic Performance of Bridge for Jin-bin Mass Transit by Pier-underpinning

The pier-underpinning of Jin-bin mass transit is taken as the research object, and ANSYS sott- ware is used in the vibration characteristics and dynamic responses analysis and pile-soil common function is con- sidered in the numerical simulation. The response Spectrum method and time history method are used to calculate the dynamic responses of the bridge structure before and after the pier-underpinning. The results show that the basic cycle of the bridge structure becomes smaller, and the maximum shear values and the maximum bending moment values of the piers bottom increase, but the maximum deflection values of the piers top decrease after the pier-underpinning. Thus the pier-underpinning improves the stiffness and seismic performance of the bridge structure system.