自锚式吊拉协作体系桥端吊索破断效应

Fracture Effects Analysis of End Hanger of Self-Anchored Cable-Stayed Suspension Bridge

目的探寻自锚式吊拉协作体系桥端吊索发生破断对结构受力性能的影响机理及规律.方法采用三维有限元模型,首先对端吊索各破断工况下的结构进行静力分析,在此基础上,引入端吊索发生破断的时间因子,对端吊索发生突然破断这一极端情况的动力过程进行准确模拟,研究端吊索发生突然破断对结构受力性能影响的动态效应.结果端吊索发生破断会引发吊拉协作体系桥缆索系统局部范围发生剧烈的内力重分布,吊索索力变化幅度最大可达70%;考虑破断时间因素的影响后,结构的内力及位移会在其静态效应基础上存在不同程度的放大,等效动态因子最大为1.09.结论端吊索发生破断会对自锚式吊拉协作体系桥缆索系统受力及安全性产生显著影响.研究结果可为该桥型缆索系统设计理论的进一步完善提供依据.

In order to research the influence of end-hanger fracture to the mechanical behavior of the struc- ture, the 3D -FEM is put forward. The static analysis of the structure in each fracture conditions of the end hanger is carried out. And then based on that, the dynamic process when the end hanger fractured suddenly is simulated by introducing the fracture time factor and the dynamic effect of end-hanger fracture to the me- chanical behavior of the structure is studied. According to the simulation results, end-hanger fracture can cause significant internal force redistribution in local range of the cable system and the maximum change am- plitude of hanger force is 70%. When the fracture time factor was considered ,the internal force and displace- ment of the bridge structure will be amplified in different degrees and the maximum equivalent dynamic fac- tor is 1.09. The results show that the end hanger fracture influences the mechanical characteristics and safety of the cable system of self-anchored cable-stayed suspension bridges significantly. The research can provide reference for improving the cable system design theory of this bridge type.