多塔矮塔斜拉桥地震反应时程分析

Seismic Response Time History Analysis of Multi-tower Extra-dosed Bridge

以主跨125m的三塔四跨单索面预应力混凝土矮塔斜拉桥为研究对象,通过建立整体三维有限元模型,首先对其进行模态分析得出结构的动力特性,然后在此基础上选取调幅后的El-Centro波作为地震动加速度时程输入,分别考虑了3种地震动输入工况,采用时程分析法对其进行地震反应分析。研究结果表明,该桥结构刚度大,基本周期短;不同地震动输入方式引起结构的地震反应差别较大,且对主梁和索塔的内力及位移影响不同,同时表明该桥抗震性能良好。

Taking the single cable plane prestressed concrete extra -dosed bridge of 125 m main span with three towers and four spans as the object of study ,firstly the modal analysis was carried out to obtain dynamic characteristics of the bridge based on the three -dimensional finite element model ,then the El-Centro wave after amplitude modulation was selected as the seismic acceleration to input ,taking into account 3 kinds of seismic input conditions respectively ,and the seismic response analysis was carried out ,using the method of time history analysis. Research results indicated that , the bridge was large stiffness and fundamental period was short ;the seismic response of the structure had great difference when seismic input different ways ,the influence on internal force and displacement of girders and towers as well ,in gen-eral ,the bridge seismic behavior was very well .