宜宾长江公路大桥斜拉桥抗震性能评价

采用单梁式有限元模型对宜宾长江公路大桥斜拉桥的动力特性和地震响应进行了计算,考虑了桩-土相互作用和群桩效应,采用反应谱法和时程分析法对该桥进行了地震反应的对比分析。计算结果表明:桥梁结构的抗震性能满足要求;抗震结构体系采用弹性索梁-塔连接体系是合适的,还可进一步降低弹性索刚度或者采用弹性索+阻尼器体系来减小桥梁地震反应;建议大跨度斜拉桥应该采用反应谱法和时程分析法同时计算,结构内力和变形以这两种方法计算结果的较大值作为抗震设计的依据。

EVALUATION OF SEISMIC RESiSTANCE CAPACITY FOR YIBIN YANGTZE RIVER CABLE-STAYED BRIDGE

A dynamic finite element model using a single-beam model has been adopted for Yibin Yangtze River cable-stayed bridge, to analyze its dynamic characteristic and seismic responses with considering the interaction between the pile and the soil as well as the effect of the pile group. The comparative analysis of the seismic response has been made by employing the response spectrum method and the time history analysis method. The analytical results show that the seismic resistance capacity of Yinbin bridge can satisfy the requirement; and the elastic cable system connecting the girder and the towers is appropriately designed for reducing the seismic response. However, the bridge seismic responses can be reduced by further loosening the stiffness or by applying the elastic cable together with the damping device system. It is suggested that the structural internal forces and deformations of long-span cable-stayed bridges should be analyzed by using both the response spectrum method and the time history analysis method, and the maximum values from these two methods should be used for the seismic design of bridges.