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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.
In view of the difficulties caused by the large number of failure modes in the reliability analysis of long-span cable-stayed bridge system and by using the engineering example of a single tower cable-stayed bridge, the paper studies the main failure modes that play a key role in the structural failure probability by using β-bounding method. The reliability of the system of cable-stayed bridge two-level system was studied.For each failure course of the main failure mode of search, the reliability index of each unit of the main tower, main girder and stay cable was calculated by using the stochastic finite element method of gradient analysis, The approximation method is used to determine the failure candidate units, and the failure of the structural system of cable-stayed bridge is equivalent to a series system composed of several parallel subsystems. The calculation results show that the failure of the stay-cable can control the failure of the structural system of the whole cable- effect.