在氯侵蚀和混凝土碳化环境下用时变可靠度和预后验决策优化桥梁检修制度

基于作者用Monte Carlo法和回归分析法开发的计算在氯侵蚀和混凝土碳化情况下混凝土梁的抗力退化随机过程的软件,用Bayes公式和桥梁检查结果更新桥梁退化状态,考虑桥梁检修的货币收益或更一般的能反映业主的财政承受能力和风险规避心理的效益函数,用预后验决策分析法给出了桥梁检查的期望效益,并以期望效益最大来优化桥梁检修制度。用北京一座混凝土梁桥为例,考虑恒载随机变量和两个Poisson随机过程活载作用下跨中抗弯承载能力极限状态,以设计基准期内任意时段的时变结构可靠度不低于桥梁设计规范的目标可靠度为条件,对这种桥梁检修制度进行优化。结果表明:用效益函数优化时,业主的财政承受能力和风险规避心理能给出明显不同的桥梁检修制度。

OPTIMUM BRIDGE INSPECTION/REPAIR ARRANGEMENT BASED ON TIME-DEPENDENT RELIABILITY AND PRE-POSTERIOR DECISION

On the basis of time-dependent reliability of deteriorating RC bridges due to pitting corrosion induced by chloride attack and average corrosion induced by concrete carbonation, bridge inspection/repair arrangement is optimized by using pre-posterior decision analysis exploring utilities of bridge inspections while utility functions relating owners’ financial capacity and risk-adverse psychology are used. Optimization of the bridge inspection/repair arrangement is maximizing the direct monetary reward or utility function with a condition that the bridge time-dependent reliability is not larger than the target reliability behind the specifications for bridge design. A computer program for such optimization method is completed on the basis of the regression analysis and Monte Carlo method. A RC bridge example shows that the optimization based on the utility function describing financial capacity and risk adverse psychology produces the arrangement clearly different from that based on the direct reward.