近远场地震作用下自复位桥墩高阶振型效应研究  

Study of Higher-Mode Effects on Self-Centering Piers Under Near-Field and Far-Field Earthquakes

作　　者：杜骞[1] 夏修身[1] 陈兴冲[1] 孙学先[1] DU Qian;XIA Xiu-shen;CHEN Xing-chong;SUN Xue-xian(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院

出　　处：《桥梁建设》2019年第6期60-65,共6页Bridge Construction

基　　金：国家自然科学基金项目(51368033,51668035);兰州交通大学优秀平台支持项目(201801)~~

摘　　要：为了研究近、远场地震作用下高阶振型对自复位桥墩地震响应的影响,以大瑞铁路漾濞1号特大桥为工程背景,基于OpenSees软件建立该桥18号桥墩(高58 m,采用自复位桥墩)的地震反应分析模型,输入近、远场地震动,通过增量动力分析法分析墩身塑性铰的形成及发展规律,并通过模态分解法计算前3阶振型对墩身塑性铰弯矩和墩顶位移的影响。结果表明:自复位桥墩并未消除高阶振型的影响,近场地震作用对结构第2阶振型的效应更加显著;墩身塑性铰主要分布在结构中部区域,且由第2阶振型控制,墩底不出现塑性铰;墩顶水平位移主要由第1阶振型控制,且远场地震作用更显著。In order to study the higher-mode effects on the seismic response of self-centering piers under near-field and far-field ground motions,the Yangbi No.1 Bridge on Dali-Ruili Railway was taken as the background project.Based on the software OpenSees,the seismic response analysis model of pier No.18 of the bridge which is a self-centering pier with a height of 58 m was established,The near-field and far-field earthquakes were input to the model to analyze the formation and development law of plastic hinges in the pier shaft by using the incremental dynamic analysis method.And the effects of the first three mode shapes on the bending moment of plastic hinges in the pier shaft and the pier-top displacement were calculated by using the modal analysis method.The results show that higher-mode effects also exist in the self-centering pier,the effect of near-field ground motions is more remarkable on the second mode of vibrations of the structure.The plastic hinges are mainly distributed in the central area of the structure and controlled by the second mode of vibrations,and no plastic hinges occur in the pier base.The horizontal displacement of the pier head is mainly controlled by the first mode of vibrations,and the effect of far-field earthquakes is more significant.

关 键 词：铁路桥 自复位桥墩 远场地震 有限元法 高阶振型效应 地震响应 

分 类 号：U24[交通运输工程—道路与铁道工程] U448.13[建筑科学—桥梁与隧道工程]