考虑关联荷载验证时变抗力的桥梁结构可靠度评估方法  

Reliability evaluation method of bridge structure considering time-varying resistance verified by correlated load

作　　者：金聪鹤 钱永久[1] 徐望喜 黄俊豪 JIN Conghe;QIAN Yongjiu;XU Wangxi;HUANG Junhao(School of Civil Engineering,Southwestern Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,成都610031

出　　处：《振动与冲击》2021年第15期146-155,共10页Journal of Vibration and Shock

基　　金：国家自然科学基金(51778532)。

摘　　要：作用于桥梁结构的荷载效应存在时间相关性。基于多维随机变量的Copula随机数矩阵和Monte Carlo数值模拟方法,提出了服从平稳随机过程的关联荷载既有桥梁时变可靠度评估方法。采用服从正态分布的历史荷载信息作为验证荷载,基于相邻荷载效应的Pearson相关系数矩阵分别构造n元Gaussian Copula和t-Copula随机数行向量,讨论了基于线性相关的荷载时间关联性强弱对桥梁时变抗力验证作用的影响。对某钢筋混凝土梁桥进行时变可靠度分析,结果表明:考虑荷载过程的时间关联性会降低其对桥梁抗力的验证作用。相关性越强,验后抗力的均值提升和标准差降低越小,验证作用越不显著;t-Copula函数的验证效果低于Gaussian Copula函数。对在役桥梁而言,已服役历史验证荷载过程的时间离散程度越高,对后继服役期结构的安全性能评估越不利。使用Copula随机数矩阵法,若采用t-Copula函数生成随机数行向量,自由度d f的取值建议在1~20之间。The load effect on bridge structure is time-dependent.Here,based on Copula random number matrix of multi-dimensional random variable and Monte Carlo numerical simulation method,a time-varying reliability evaluation method for existing bridges with correlated load subject to stationary random processwas proposed.Taking historical load information subject to normal distribution as verification load,based on Pearson correlation coefficient matrix of adjacent load effects,N-element Gaussian Copula and t-Copula random number row vectors were constructed,respectively,and influences of load time correlation based on linear correlation on verification effect of bridge time-varying resistance were discussed.The time-varying reliability analysis was performed for a reinforced concrete beam bridge.The results showed that considering time correlation of load process can reduce its verification effect on bridge resistance;the stronger the correlation,the smaller the increase in mean value of resistance after verification and the decrease in its standard deviation,and the lesssignificant the verification effect;the verification effect of t-Copula function is lower than that of Gaussian Copula function;for bridges in service,the higher the time dispersion degree of load process verified by service history,the more unfavorable to the safety performance evaluation of structure in subsequent service period;using Copula random number matrix method proposed here,if t-Copula function is used to generate random number row vector,the value of degree of freedom d f is suggested to be 1~20.

关 键 词：时变可靠度 平稳随机过程 荷载关联性 验证荷载 正态分布 Copula随机数矩阵 

分 类 号：U441.2[建筑科学—桥梁与隧道工程]