基于虚拟变量法的某连续梁桥施工期可靠性分析

Reliability Analysis of a Continuous Girder Bridge during Construction Based on Dummy Variable Method

连续梁桥一般采用悬臂浇筑进行施工,各施工阶段浇筑完成的悬臂构件可靠性都能够对下一施工阶段可靠性造成影响,进而影响到整个桥梁的建造安全性。以湘水大桥为工程背景,以主梁,墩柱,桩基结构、临时固结系统作为结构的失效模式,在充分考虑工程实际的基础上,基于虚拟变量法对各施工阶段可靠指标进行计算,进而计算了整个施工期的体系可靠度。计算结果表明:每个施工阶段主梁及各截面可靠度指标幅度变化相对较大,而临时固结系统及桩基础的可靠度指标幅度变化表较小,整个施工期的体系失效概率P_(f)=0.0015。

Continuous girder bridge is usually constructed by cantilever casting,and the reliability of cantilever components completed in each construction stage can affect the reliability of the next construction stage,and then affect the construction safety of the whole bridge.This paper takes a continuous girder bridge as the engineering background,main girder,pier column,pile foundation structure and temporary consolidation system as the failure mode of the structure.On the basis of fully considering the engineering practice,the reliability index of each construction stage is calculated based on the dummy variable method,and then the system reliability of the whole construction period is calculated.The calculation results show that the reliability index range of the main girder and each section varies relatively greatly in each construction stage.But the range of reliability index of temporary consolidation system and pile foundation is small.System failure probability during the entire construction period P_(f)=0.0015.