大跨度斜拉桥地震响应非线性时程分析

以有限元分析理论为基础,结合某大跨度斜拉桥工程实例,利用ANSYS软件建立有限元模型,通过修正后的El Centro波分别考虑横向、竖向及纵向输入,采用时程分析方法对其进行地震反应分析.计算分析表明:考虑几何非线性后,结构的内力和位移响应明显增大,且对主梁和索塔内力与位移的影响程度及规律也不尽相同,须区别对待分析.同时表明该桥抗震性能良好,地震荷载不控制设计.由此得出结论,对于斜拉桥这类柔性体系, 不可忽视结构几何非线性的影响.

Nonlinear time-history analysis of seismic response of a long-span cable-stayed bridge

Based on the theory of finite element analysis and with reference to one long-span cable-stayed bridge, the bridge model is established by the software of ANSYS. The seismic response of the bridge under the El Centro wave is obtained by time-history analysis method,the El Centro wave is adjusted,and is inputted from longitudinal, transverse and vertical direction,respectively. The computed results indicate that the internal force and displacement are influenced obviously by the geometric nonlinear effect more than the linear effect. For the internal force and displacement of the girder and tower under the seismic ground motion, the effect and the rules of the seismic responses are different from nonlinear geometric effect. The results also show that the bridge has a good seismic performance, and the bridge design is not controlled by the seismic load. As a result, the geometric nonlinear effect must be considered in the seismic response analysis of the cable-stayed bridges.