局部场地效应下超千米跨度公铁两用斜拉桥时频域地震响应研究  

Time-frequency Domain Seismic Response of Super-kilometer-span Cable-stayed Rail-cum-road Bridge Considering Local Site Effect

作　　者：张金 陈克坚[1] 曾永平[1] 郭恒 郑史雄[3] 范晨阳[3] ZHANG Jin;CHEN Kejian;ZENG Yongping;GUO Heng;ZHENG Shixiong;FAN Chenyang(China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031,China;School of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]中铁二院工程集团有限责任公司,四川成都610031 [2]成都理工大学环境与土木工程学院,四川成都610059 [3]西南交通大学土木工程学院,四川成都610031

出　　处：《铁道学报》2023年第2期154-164,共11页Journal of the China Railway Society

基　　金：国家自然科学基金(52008047);中国博士后科学基金(2020M673294);中铁二院工程集团有限责任公司博士后研究课题(KSNQ201062)。

摘　　要：为在时、频域范围内量化场地效应对超千米跨度公铁两用斜拉桥地震响应的影响,基于加速度功率谱模型并结合不同的场地条件细化模型参数,采用虚拟激励和多点时程分析法,分别在时、频域范围内开展超千米跨度公铁两用斜拉桥地震响应分析,并将结构地震响应进行对比,结果表明:对于主梁主跨,柔软场地工况下的主梁位移、内力响应最大,坚硬场地工况下的响应最小,其他工况均介于两者之间且呈规律性变化,柔软场地工况下的主梁内力响应较坚硬场地下的响应最大相差407%;考虑各局部场地效应工况对主梁左边跨地震响应影响,区别于主梁主跨,主梁左边跨位移、内力响应除在柔软场地工况下出现最大值外,其他场地工况下的地震响应值交替变化,变化规律并不完全明确。综合考虑各局部场地工况,采用时程分析法斜拉桥地震响应计算结果总体大于频域虚拟激励法计算结果,各关键地震响应增大率介于9%~182%。因此,对于超千米跨度公铁两用斜拉桥抗震分析,频域方法可能会低估其地震响应,为准确评估斜拉桥动力响应,时程分析法依然是首选的抗震分析方法。In order to quantify the impact of site effects on the seismic response of super-kilometer-span cable-stayed rail-cum-road bridges in the time and frequency domains,the model parameters were refined based on the acceleration power spectrum model and combined with different site conditions.The pseudo excitation method and multiple points time-history analysis method were used to carry out the seismic response comparative analysis of the super-kilometer-span cable-stayed rail-cum-road bridge in the time and frequency domains.The results show that for the girder with the main span,the displacement and internal force response of the girder under soft site conditions are the largest,and the response under hard site conditions is the smallest.The seismic response under other conditions is between the limit response and change regularly.The internal force response of the girder under the soft site conditions is very different from the response under the hard site,with a maximum difference of 407%.Considering the influence of each local site effect condition on the seismic response of the girder with the left span,which is different from the main girder with the main span,the displacement and internal force response of the main girder with the left span vary alternately under other site conditions,except for the maximum value under the soft site conditions,and the change law is not completely clear.Taking into account the working conditions of various local sites,the seismic response calculation results of cable-stayed bridges using time-history analysis are generally greater than those calculated by the pseudo excitation method in the frequency domain,with the increasing rate between 9%and 182%of each key seismic response.Therefore,for the seismic analysis of a cable-stayed bridge with super-kilometer span,the frequency domain method may underestimate its seismic response.In order to accurately assess the dynamic response of the cable-stayed bridge,the time history analysis method is still the preferred seismic analysis

关 键 词：超千米跨度斜拉桥 局部场地效应 地震波合成 虚拟激励法 时程分析法 

分 类 号：TU311.3[建筑科学—结构工程]