大跨度斜拉桥恒载非线性静力分析

Nonlinear static analysis of long-span cable-stayed bridges under dead loads

静力分析的精确程度对大跨度斜拉桥设计和施工过程具有很大影响。提出一套有限元方法 ,以弯曲能量作为目标函数确定斜拉索的初始张拉力 ,通过修正斜拉索的弹性模量 ,引入几何刚度矩阵和大挠度矩阵 ,综合考虑斜拉索垂度效应、梁柱效应和大位移效应 ,采用混合法求解系统方程。程序经过算例验证并应用于在建的重庆大佛寺长江大桥 ,取得了较好的效果 。

Long-span cable-stayed bridges exhibit highly geometrically nonlinear behavior. The accuracy of their static analysis plays an important role during the design and construction processes. A finite element computation procedure was presented which includes the cable sag effect, the beam-column effect and the large displacement effect by modifying the elastic modulus of the cable and by introducing a geometric stiffness matrix and a large displacement matrix. The bending strain energy was chosen as the objective function to calculate the initial cable forces. An iterative-incremental procedure is described to solve the nonlinear system of equations. The method was used to analyze the Dafusi bridge, in Chongqing. The results provide a basis for the construction control.