近断层脉冲型地震动作用下简支梁桥地震响应与损伤分析  

Seismic response and damage analysis of simply supported beam bridges under near-fault pulse-type ground motions

作　　者：韩建平[1] 柴文阳 石岩[1] 刘云帅[1] HAN Jianping;CHAI Wenyang;SHI Yan;LIU Yunshuai(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,Gansu,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050

出　　处：《地震工程学报》2025年第2期251-262,280,共13页China Earthquake Engineering Journal

基　　金：甘肃省重点研发计划(22YF7GA161);甘肃省教育厅青年博士支持项目(2023QB-031)。

摘　　要：为探究简支梁桥在近断层脉冲地震动作用下的地震响应特征和损伤情况,采用单一函数解析模型模拟近断层地震动中的低频脉冲成分,并与实测地震动滤波后得到的高频成分相叠加,合成得到近断层脉冲型地震动作为输入;以一座4跨简支梁桥为原型,建立有限元数值模型,通过非线性地震反应时程分析,系统研究近断层脉冲型地震动断层距、矩震级、脉冲次数和合成地震动的高频成分等对简支梁桥桥墩的墩顶位移和损伤状态、主梁的位移和碰撞力的影响。结果表明:(1)地震动低频成分是脉冲峰值的主要影响因素,简支梁桥的地震响应强烈程度主要由地震动中的低频脉冲成分决定;(2)在地震动的矩震级较小时,由于单次脉冲的峰值大于多次反复脉冲,简支梁桥的地震响应更加明显;反之,桥梁在多次反复的脉冲作用下地震响应更大;(3)地震动中高频成分对结构的地震响应影响较小,但会影响桥梁的峰值和残余位移,其影响亦不可忽视。In this study,a single analytical model was employed to simulate the low-frequency impulsive components in near-fault ground motions,facilitating the investigation of the seismic response characteristics and damage of simply supported beam bridges under near-fault pulse-type ground motions.These components were superimposed with the high-frequency components obtained from the actual near-fault ground motion data after filtering,resulting in a synthesized near-fault pulse-type ground motion as the input.Then,a finite element numerical model was established using a four-span simply supported beam bridge as a prototype.Nonlinear seismic response time-history analysis was conducted to systematically study the effects of factors,including fault distance,number of impulsive pulses,moment magnitude,and the high-frequency components of the synthesized ground motion on the top displacement and damage state of bridge piers,along with the displacement and collision forces on the main beams.The results revealed that the low-frequency components of the ground motion served as the primary influencing factors on the impulsive peak values.Furthermore,the low-frequency impulsive components in the ground motion were used to determine the intensity of the simply supported beam bridge.When the moment magnitude of the ground motion was relatively small,the seismic response of the simply supported beam bridge was greater due to the larger peak value of a single impulsive pulse compared to multiple repeated pulses.Conversely,for ground motions with larger moment magnitudes,the seismic response of the bridge was greater under the action of multiple repeated pulses.The high-frequency components in the ground motion had a relatively minor impact on the structural seismic response;however,they affected the peak and residual displacements of the bridge.The study's findings underscore the fact that the influence of high-frequency components on structural response should not be overlooked during damage analysis.

关 键 词：近断层地震动 脉冲效应 人工合成地震动 双柱式排架墩 地震响应 

分 类 号：P319.56[天文地球—固体地球物理学]