大跨径连续刚构桥的随机地震动响应分析

以苏通长江大桥辅航道桥为工程背景,考虑结构自重引起几何非线性以及桩土相互影响,建立该桥的地震分析模型,分析行波效应、部分相干效应和局部场地效应对结构地震响应的影响规律。结果表明:行波效应总体上削弱结构的位移响应,对内力响应的影响较大,在相位差为1s的情况下,面内弯矩响应的增幅达到25%;局部场地效应对内力及位移响应的影响均较大;相干效应削弱桥梁主墩的弯矩响应。

Stochastic Seismic Response Analysis of Long-span Continuous Rigid Frame Bridge

In this paper, by taking the under-construction approach bridge of Sutong Yangtze River Bridge as the engineering background, the dynamic model is established considering the geometrical nonlinearity caused by the dead-load and the soil-foundation-structure interaction effect. Based on this model, the stochastic seismic (response) on the bridge is analyzed, and The spatial varying ground motion effect including the wave passage effect, the ground motion coherence effect and the local-spatial variation effect are studied in detail, and the rules of how they affect the seismic response are derived: the wave passage effect cuts down the displacement response of the structure but affects greatly on the moment response. While the delay reaches 1 s, the in-face moment (increases) by 25%; the local-spatial variation effect performs a great effect on the moment and displacement responses. In the analysis of ground motion coherence effect, the moment response of the main pier was cut down by interrelated effect.