不同场地下大跨斜拉桥多维多点随机地震响应分析  

Multi-Dimensional and Multi-Point Random Seismic Response Analysis of Long-Span Cable-Stayed Bridges at Different Sites

作　　者：石燚 陆路 范书立 沈檬 左春愿 孙新国 曹飞飞 SHI Yi;LU Lu;FAN Shuli;SHEN Meng;ZUO Chunyuan;SUN Xinguo;CAO Feifei(College of Management and Engineering,Huaiyin Institute of Technology,Huai’an,Jiangsu 223003,China;School of Infrastructure Engineering,Dalian University of Technology,Dalian,Liaoning 116023,China)

机构地区：[1]淮阴工学院管理工程学院,江苏淮安223003 [2]大连理工大学建设工程学部,辽宁大连116023

出　　处：《中外公路》2024年第5期158-165,共8页Journal of China & Foreign Highway

基　　金：国家自然科学基金资助项目(编号:51678107);江苏省自然科学基金资助项目(编号:BK20191050);江苏省高校自然科学研究项目(编号:18KJD560001,22KJD180001);江苏省高校哲学社会科学项目(编号:2019SJA1659)。

摘　　要：为了研究不同场地下大跨斜拉桥随机地震响应,该文采用场地传递函数评估不同场地条件对地震动传播的影响,综合考虑行波效应及相干效应,生成了不同场地条件的多点功率谱,运用绝对位移求解的虚拟激励法对斜拉桥在不同场地下的一致激励及多点多维的地震响应进行对比分析。选取一大跨斜拉桥作为工程实例,采用Ansys有限元软件进行随机地震响应分析;考虑场地条件对地震功率谱的影响,计算桥梁结构在不同激励方式下的随机响应,提取桥梁各单元响应的功率谱,并计算功率谱响应的均方根极值。研究结果表明:软土场地对桥梁随机响应的放大效应约为硬土场地的3倍;多点激励对桥梁随机响应的放大影响约为一致激励的1.5倍。因此,场地效应对大跨斜拉桥梁的随机地震响应影响极大,在抗震设计时不能忽略其影响。To study the random seismic response of long-span cable-stayed bridges at different sites,the site transfer function was used to evaluate the influence of different site conditions on ground motion propagation.By considering the traveling wave effect and the coherence effect,the multi-point power spectrum under different site conditions was generated.By using the pseudo excitation method for solving the absolute displacement,the seismic responses of cable-stayed bridges under uniform excitation and multi-dimensional and multi-point excitation at different sites were compared.A long-span cable-stayed bridge was selected as an example,and Ansys finite element software was used to analyze the random seismic response of the bridge.By considering the influence of site conditions on the seismic power spectrum,the random responses of the bridge under different excitation modes were calculated,and the power spectrum of each element of the bridge was extracted.The extreme root mean square of the power spectrum response was calculated.The results show that the amplification effect of soft soil on the random response of the bridge is about three times that of hard soil,and the amplification effect of multi-point excitation on the random response of the bridge is about 1.5 times that of uniform excitation.Therefore,the site effect has a great influence on the random seismic response of long-span cable-stayed bridges,and its influence cannot be ignored in bridge design.

关 键 词：大跨斜拉桥 随机响应 场地传递函数 功率谱密度函数 虚拟激励法 

分 类 号：U443[建筑科学—桥梁与隧道工程]