斜拉桥体系可靠度分析

针对大跨度斜拉桥体系可靠度分析中由于失效模式众多带来的困难，结合某独塔斜拉桥的工程实例，应用β约界法搜索对结构失效概率起关键作用的主要失效模式，研究了斜拉桥2级体系可靠度.在搜索主要失效模式的各失效历程中，采用梯度分析随机有限元法计算斜拉桥主塔、主梁和斜拉索各个单元的可靠度指标，应用β约界法确定失效候选单元，将斜拉桥结构体系的失效等效为一个由若干并联子系统构成的串联系统.计算结果表明，斜拉索的失效对整个斜拉桥结构体系的失效起控制作用.

System reliability analysis of cable-stayed bridge

Aiming at the difficulty from too many failure modes in the system reliability analysis of long span cable stayed bridges, β unzipping method was used to search the main failure mode with key effect on the failure probability of a single pylon cable stayed bridge, and the 2 level system reliability of the cable stayed bridge was investigated. During searching various failure course of main failure mode, the gradients based stochastic finite element reliability method was used to calculate the reliability indices of such components as main pylon, main girder and stayed cable. The critical failure units in different failure levels were chosen using β unzipping method. The failure of the bridge was considered as a series system comprised of parallel subsystems. The calculation results show that the failure of stay cable plays a control role in the failure of whole cable stayed bridge.