考虑行波效应下大跨度钢拱桥的地震反应分析

Seismic Response Analysis for Long-span Arch Bridgesunder Consideration of Traveling Wave Effect

以一座主跨为260m的中承式钢拱桥为实例,采用大质量法实现行波效应下的多点激励,对该桥进行了考虑行波效应下的地震反应分析.选取5组截面,探讨了考虑行波效应时不同相位差对该桥地震反应的影响,并与一致激励地震动输入下桥梁的地震反应进行了对比分析.结果表明:考虑行波效应比一致激励作用下该桥的地震反应有增大的趋势,当相位差最大为5.2 s时,5组截面中竖向位移、轴力和横向弯矩峰值分别是一致激励下的10.9、6.5和5.1倍,并且在考虑行波效应时随着相位差的减小,结构的位移和内力均呈现减小的趋势.在大跨径桥梁抗震设计中应考虑行波效应的影响.

According to the traveling wave effect on the seismic response of large span structure,this paper took a main span of 260 meters of half-through steel arch bridge as an example and used large mass method to realize multi-support excitation of traveling wave effect.Through selecting five sections,study on the traveling wave effect of seismic response of bridge were made under diverse phase difference,and the comparative analysis with result of uniform excitation were carried out.The calculation showed that the former seismic response was greater than the latter＇s and the peak of vertical displacement,axial force and transverse moment was respectively 10.9,6.5 and 5.1 times of the latter＇s when the phase difference was 5.2s.With decrease of the phase difference,the displacement and internal force of the structure present decreasing trend when considering the traveling wave effect.Therefore,the traveling wave effect should be considered in the aseismic design of long-span Bridges.