减震措施及行波效应对千米级斜拉桥地震响应的影响

Influence of Shock Absorption Measures and Traveling Wave Effect on Seismic Response of Kilometer Grade Cable-Stayed Bridge

基于一座主跨1 500 m的斜拉桥设计方案建立了有限元分析模型,通过参数敏感性分析初步拟定了本桥纵向减震装置的合理设计参数;对塔、梁纵桥向采用3种不同约束方式的结构设计方案,采用大质量法分别分析了行波效应对结构地震响应的影响。研究表明:考虑行波效应后对于3种不同的塔、梁纵桥向约束方式的结构设计方案,主塔结构的内力响应均有可能增大20%左右。因此,在千米级斜拉桥的抗震设计中,无论是否采用纵桥向减震措施,若不考虑行波效应问题都可能导致偏于不安全的设计结果。

Based on the design scheme of a cable stayed bridge with a main span of 1500 m, a finite element analysis model was established; and the reasonable design parameters of the longitudinal damping device of the bridge were developed through the parameter sensitivity analysis. For the structural design scheme of tower and girder longitudinal bridges with three different restraint modes, the influence of traveling wave effect on the seismic response of the structure was analyzed by large mass method （LMM）. The results show that the internal force response of the main tower structure may be increased by about 20%, after considering the traveling wave effect on the structural design scheme of tower and girder longitudinal bridges with three different restraint modes. Therefore, in the seismic design of kilometer grade cable stayed bridge, whether longitudinal damping measures are adopted or not, if the traveling wave effect is not considered, it may lead to unsafe design results.