基于贝叶斯更新和荷载信息的桥梁时变可靠度评估

Time-varying Reliability Evaluation of Bridges Based on Bayesian Updating and Load Information

恶劣环境和不断增加的交通量下在役桥梁随时间逐渐劣化,开展桥梁可靠度评估意义重大。以随机过程表征抗力退化,利用历史荷载试验信息并结合贝叶斯方法更新服役桥梁抗力,获得抗力截尾分布,进而提出了桥梁时变可靠度计算方法,并以一座混凝土实桥为例,演示了抗力更新与时变可靠度评估。结果表明,服役20年桥梁抗力均值通过荷载信息更新后,变异系数由0.119减小为0.110,减小了抗力评估的不确定性,且更新后的可靠指标明显大于更新前,未考虑荷载信息评估低估了桥梁的可靠性。本研究可为在役混凝土桥梁后期维修加固决策提供理论指导。

Under hostile environment and increasing traffic volume,bridges in service gradually deteriorate over time,so it is of great significance to carry out bridge reliability evaluation.The resistance degradation was characterized by random process,the resistance of bridges in service was updated by using historical load test information and Bayesian method to obtain the truncated distribution of resistance,and then the time-varying reliability calculation method of bridges was proposed.A concrete bridge was taken as an example to demonstrate the resistance renewal and time-varying reliability evaluation.The results show that the coefficient of variation of the mean value of resistance of bridges in service for 20 years decreases from 0.119 to 0.110 after the load information is updated,which reduces the uncertainty of resistance evaluation,and the reliability index after the update is significantly larger than that before the update,which underestimates the reliability of bridges without considering the load information evaluation.This study can provide theoretical guidance for the decision of maintenance and reinforcement of concrete bridges in service.