预应力混凝土梁桥系统失效树分析

针对预应力混凝土梁桥,采用失效树的方法进行系统可靠性分析。运用全局临界强度分枝-约界准则识别结构系统主要失效模式,以JC法计算各主要失效模式的可靠指标,采用Ditlevsen上下界公式分析结构体系的失效概率。以某汉江公路大桥为例,分析了失效树图形,研究了主要失效模式的可靠指标、失效概率及桥梁结构体系可靠性。与实桥运营状态的对比分析表明,上述理论分析较好地预测了实际的结构行为,能用于桥梁结构安全性及可靠性分析评估。

FAULT TREE ANALYSIS OF PRESTREESED CONCRETE BEAM BRIDGES

The probability of the prestressed concrete beam bridge is analyzed based on Fault Tree method.The dominant failure modes are identified using the overall critical strength branch-and-bound criterion firstly,and then,the reliability index of these modes is calculated by JC method.Finally,the failure probability of the structural system is calculated with Ditlevsen upper and lower bounds formula.This procedure is illustrated by taking a highway bridge over the Hanjiang River in China as an engineering example.A comparison with the real running state of the bridge shows that the proposed procedure can predict the structural behavior of practical bridges and can be applied to analyzing and evaluating the safety and reliability of the prestressed concrete bridge.