高烈度区曲线斜拉桥地震反应特性分析

Seismic Response Analysis of Curved Cable-Stayed Bridge in High Intensity Area

针对高烈度区曲线斜拉桥工程,采用有限元软件SAP2000建立动力分析模型,并结合曲线桥的特点确定地震动输入方向,进而对桥梁动力特性与地震反应进行分析,其中重点关注曲线斜拉桥的耦合效应。结果表明:桥梁关键位置处在各阶振型下各方向的位移耦合现象较明显;内、外侧斜拉索的动索力相差约20%,将引起主塔截面扭矩,但影响不大;曲线桥存在较为明显的双向弯矩耦合效应,使截面受力更为不利。高烈度区曲线斜拉桥的抗震设计是一个亟须关注的问题。

In view of the curved cablestayed bridge project in high intensity area,the finite element software SAP2000is used to establish the dynamic analysis model,and the seismic input direction is determined according to the characteristics of the curved bridge.Then the dynamic characteristics and seismic response of the bridge are analyzed,with the emphasis on the coupling effect of the curved cable-stayed bridge.The results show that the coupling phenomenon of displacement in all directions is obvious at the key position of the bridge under each mode of vibration;the difference of dynamic cable forces between inside and outside cable-stayed cables is about20%,which will cause the torsion of the main tower section,but the influence is not significant;there is a more obvious coupling effect of two-way bending moments in curved bridges,which makes the stress of the section more unfavorable.Seismic design of curved cable-stayed bridges in high intensity areas is an urgent issue.