大跨度斜拉桥结构系统可靠度评估

Structural system reliability evaluation of long-span cable-stayed bridges

为实现桥梁结构系统可靠度的快速评估,将响应面法、有限元法、β约界法和条件概率乘积算法等方法各自优点相结合,提出了1种计算结构系统可靠度的近似方法.该近似方法采用响应面法和有限元法构造结构单元的极限状态方程,并计算可靠指标;采用β约界法和条件概率乘积算法建立结构系统,并计算失效概率.应用计算结构系统可靠度的近似方法进行了主跨1 088 m的苏通大桥的结构系统可靠度分析和评估,结果表明:该近似方法在寻找建立结构串联和混联系统方面具有很高的效率和精度,其混联系统可靠指标略大于串联系统可靠指标,为今后其他桥梁的结构系统可靠度评估提供了思路.

Combining the advantages of response surface method（RSM）,finite element method（FEM）,β-unzipping method and product of conditional marginal method（PCM）,an approximate method was proposed to rapidly evaluate the reliability of bridge structure system.The component reliability indices were calculated by FEM and RSM,while the β-unzipping method and PCM method were employed to calculate critical failure modes and system failure probability.The structure system reliability of cable-stayed Sutong Bridge with a main span length of 1 088 m was conducted by the proposed approximate method.The obtained results clearly show the applicability and merits of the proposed method in the identification of critical failures modes,and the reliability indices for hybrid system are slightly larger than those for series system.The proposed method provides convenience for the system reliability evaluation of other bridge structures.