基于场地效应的悬索桥随机地震响应分析

Random Seismic Response of a Suspension Bridge Considering Site Effect

摘要:

因大跨径悬索桥梁具有较大的跨越尺度，同时墩柱基础所处场地条件也存在差异，所以对其进行地震响应分析时需考虑局部场地效应。为了正确分析场地效应对大跨度桥梁的地震响应，以某悬索桥为研究背景，采用MIDAS/CIVIL有限元软件，建立该悬索桥的有限元模型，在考虑地震动的局部场地效应情况下列举9种不同的计算工况，对大跨度悬索桥进行时程分析，通过控制一个塔墩处场地类别，改变另一个塔墩处的场地类别来分析场地效应对桥梁跨中位移和弯矩的影响。研究结果显示：场地效应对悬索桥的跨中位移和弯矩存在一定影响，不同的场地条件对桥梁同一位置的破坏程度不同。

Abstract:

The local site effect should be considered when analyzing the seismic response of long-span suspension bridges because of the large span scale and different site conditions of pier column foundation. For such analysis, the finite element model of a certain long-span suspension bridge is established in this paper using the MIDAS/Civil finite element software. Considering the local site effect of ground motions, nine different calculation conditions are listed to carry out the time-history analysis of the long-span suspension bridge. By controlling the site classification of one tower pier and changing the site classification of another tower pier, the influence of site effect on the midspan displacement and bending moment of the bridge is analyzed. The results show that site effect has some impacts on the midspan displacement and bending moment of suspension bridges, and different site conditions have different levels of destruction on the same position of the bridge.