沪蓉西四渡河悬索桥抗震性能研究

Seismic Performance Study of Sidu River Suspension Bridge Located in the West of Hu-rong National Highway

大跨度悬索桥必须进行可靠的抗震性能研究。以一座在建的山区悬索桥为研究对象,采用基于迭代拟合规范设计反应谱法合成一致激励、行波效应以及多点激励3种工况下的位移时程,并作为该桥地震动输入。采用两水准设防二阶段抗震设计方法,分别按纵向+竖向、横向+竖向对其进行线性和几何非线性地震时程分析。分析结果表明:多点激励的影响较大,线性与几何非线性分析结果较接近;经抗震强度、变形验算,该桥抗震性能满足要求。

It is necessary for long span suspension bridges that the reliable seismic performance analysis is carried out. The montane suspension bridge building is dealt with an object, an itera-tive method of developing acceleration time-history compatible with design response spectrum is adopted to simulate uniform excitation, travelling wave effect and multi-point excitation which are used as the earthquake ground motions input for the bridge, respectively. According to two-phase seismic fortification criterion, linear and geometry non-linear seismic time-history analyses are conducted under two kinds of input combinations, i.e., longitudinal & vertical direction and lateral & vertical direction. Finally, it is indicated that multi-support excitation effect affects greatly and linear and nonlinear calculation results are very close. Furthermore, seismic safety performance of the whole bridge is ensured through the seismic strength and deformation checking computations.