摘要
为了表征桥梁结构不确定性和随机参数相关性对桥梁结构抗震性能的影响,从概率角度对桥梁进行抗震性能分析,基于部分分层抽样原理建立了时-频非平稳地震作用下桥梁非线性随机地震响应分析方法。基于地震动演化功率谱,采用谱表示方法生成非平稳地震动样本,并采用基于正交函数的思想对谱表示方法中的随机变量进行模拟,通过两个基本随机变量表征地震动的不确定性;采用基于数论的部分分层抽样方法对地震动-结构随机变量抽样,从而对桥梁非线性随机地震响应进行模拟,减小桥梁随机地震响应分析中的抽样方差;以一座实际高墩连续刚构桥为数值算例,对其进行了非线性随机地震响应分析,详细研究了桥梁结构不确定性和随机参数相关性对其地震可靠度的影响。研究结果表明:随机地震作用下,桥梁随机地震响应是典型的零均值非平稳随机过程,从地震动开始到结束,桥梁结构地震响应概率密度曲线存在由窄边宽,再由宽变窄的演化过程;随机地震作用下,桥梁结构关键响应的平均峰值因子存在一定差异,其通常在1.8~2.2变化;桥梁结构不确定性和随机参数相关性对高墩桥梁地震响应极值分布和地震可靠度的影响较为显著,忽略桥梁结构的不确定性和随机参数相关性将高估桥梁结构的地震可靠度。
Here,to characterize effects of bridge structure uncertainty and random parametric correlation on aseismic performance of bridge structure,the aseismic performance of bridges was analyzed from the perspective of probability.Based on the principle of partial stratified sampling,the nonlinear random seismic response analysis method of bridges under time-frequency nonstationary earthquake was established.Firstly,based on the evolutionary power spectrum of ground motion,the spectral representation method was used to generate non-stationary ground motion samples,and random variables in the spectral representation method were simulated based on the idea of orthogonal functions,and two basic random variables were used to characterize the uncertainty of ground motion.Then,random variables of the ground motion-structure system were sampled using the partial stratified sampling method based on number theory to simulate the nonlinear random seismic response of bridge and reduce the sampling variance in random seismic response analysis of bridge.Finally,a practical high-pier continuous steel frame bridge was taken as a numerical example to analyze its nonlinear random seismic response,and effects of bridge structural uncertainty and random parametric correlation on its seismic reliability were studied in detail.The results showed that the random seismic response of bridge under random earthquake is a typical zero mean non-stationary random process,from the beginning to the end of ground motion,the probability density curve of seismic response of bridge structure has an evolutionary process from narrow to wide,and then from wide to narrow;under random earthquake,average peak factors of key responses of bridge structure have some differences,they usually vary in the range of 1.8-2.2;effects of bridge structure uncertainty and random parametric correlation on seismic response extreme value distribution and seismic reliability of high-pier bridge are more significant,ignoring uncertainty and random parametric correlation of brid
作者
陈志强
郑史雄
丁自豪
张金
CHEN Zhiqiang;ZHENG Shixiong;DING Zihao;ZHANG Jin(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2022年第7期214-222,234,共10页
Journal of Vibration and Shock
基金
主持国家自然科学基金(U1434205,52008047)
四川省科技计划(2020YJ0081)。
关键词
非平稳
随机地震响应
极值分布
地震可靠度
部分分层抽样
non-stationary
random seismic response
extreme value distribution
seismic reliability
partially stratified sampling
