模糊及随机信息下桥梁构件抗力演化特征分析

Analysis for evolutionary characteristics of resistance degradation of bridge members under fuzzy and random information

受时间、空间以及检测手段等的限制,服役桥梁结构抗力退化预测过程存在很大的不确定性,这些不确定性既包括模糊性又包括随机性。针对氯盐环境下钢筋混凝土桥梁中钢筋局部锈蚀,以一座拆除旧桥构件为背景,构建了模糊及随机信息条件下桥梁构件抗力演化分析框架,模拟了钢筋锈蚀率和强度退化概率特征,并结合试验结果进行了验证,在此基础上,进一步考虑锈蚀引起黏结退化影响,分析了构件抗力概率密度函数演化特征,得到了抗力均值和标准差时变特点和截口分布类型。研究表明:信息的模糊性对预测结果影响不容忽视,对于信息不完善的桥梁或构件,抗力预测分析过程中系统地考虑这些不确定性因素是必要的。

The prediction of structural resistance degradation is limited by the inspection means, the time and the space of the reinforced concrete bridges in service, and the uncertainties, including fuzziness and randomness of intluencing lectors, need to be considered. A demolished bridge is chosen as the engineering case. The analytical framework of resistance evolution due to chloride-induced pitting corrosion of reinforcement is established to consider the random and fuzzy information. The probabilistic characteristics of corrosion rate and strength loss in reinforcing bar are simulated and verified by the experimental results. Furthermore, the effect of corrosion on bond properties between reinforcement and concrete is considered, and the evolutionary characteristics of probability density function of resistance are analyzed. Besides, the probabilistic distribution pattern and distribution parameters are also obtained. The results show that the effect of fuzzy inionnation on tire prediction can not be ignored. It is necessary to consider these uncertain factors in resistance evolutionary prediction for bridges or members due to incomplete information.