跨走滑断层大跨度桁架悬索桥地震响应分析  

Seismic Response Analysis of Large-span Truss Suspension Bridge Across Strike-slip Faults

作　　者：邹作家 郑史雄[1] 丁自豪 贾宏宇[1] 余琦 程维 ZOU Zuojia;ZHENG Shixiong;DING Zihao;JIA Hongyu;YU Qi;CHEN Wei(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,成都610031

出　　处：《铁道标准设计》2024年第7期92-100,共9页Railway Standard Design

基　　金：国家自然科学基金项目(52178169)。

摘　　要：跨越断层的长大跨度桥梁难免会受到断层错动作用,为探究跨走滑断层地震动参数对大跨度悬索桥地震响应的影响,以某主跨为538 m的钢桁架悬索桥为例,利用ABAQUS建立考虑桩-土相互作用(“m”法)的全桥有限元模型。通过叠加人工低频地震成分和实际高频地震成分,合成了跨走滑断层地震动,采用非一致激励位移时程法,重点分析永久位移、脉冲周期和跨断层角度对大跨度悬索桥的动力响应影响。结果表明:随着永久位移增大,桥塔动力响应呈不同幅度的增长,特别是横桥向位移、剪力,以及顺桥向弯矩增幅比较明显,分别增大97%、88%和95%,且剪力的增大加剧了桥塔发生剪切破坏的风险;随着脉冲周期减小,桥塔沿顺桥向和横桥向的动力响应增幅差距较大,当脉冲周期小于4 s时,桥塔横桥向位移、剪力,以及顺桥向弯矩相较于另一方向增幅更为明显,其增幅分别为492.5%、170%和189.2%;跨断层角度对桥塔的动力响应影响较大,且沿顺桥向和横桥向的响应变化趋势相反,跨断层角度为90°时,桥塔横桥向位移、剪力取得最大值,而弯矩取得最小值,且桥塔动力响应均在合理范围内,为最佳跨越角度。Long-span bridges across faults may inevitably suffer fault dislocation.To explore the influence of ground motion parameters across strike-slip fault on the seismic responses of long-span suspension bridge,a whole bridge finite element model considering pile-soil interaction(m method)is established based on ABAQUS by taking a steel-truss suspension bridge with a main-span of 538 m as an example.Ground motions of strike-slip fault are synthesized by combining the artificial low-frequency and actual high-frequency seismic components,and the effects of permanent displacement,pulse period and cross-fault angle on the dynamic responses of long-span suspension bridge are investigated based on the non-uniform excitation displacement time history method.Results indicate that the growths in dynamic responses of bridge tower show different magnitudes with the increase of permanent displacement,especially the transverse displacement and shear force,as well as the longitudinal moment,which increase by 97%,88%and 95%respectively.The increase of shear force aggravates the risk of shear failure of bridge tower.The decrease of the pulse period will lead to a large difference between the longitudinal and transverse dynamic responses of the bridge tower.When the pulse period is less than 4s,the transverse displacement and shear force,as well as longitudinal moment of bridge tower increase more obviously than in the other direction,and the increases are 492.5%,170%and 189.2%respectively.Cross-fault angle has significant influence on the dynamic responses of the bridge tower,and the changes along the longitudinal and transverse directions tend to be opposite.When the cross-fault angle is 90°,the transverse displacement and shear force of bridge tower are the maximum,while the corresponding moment is the minimum,and the dynamic response of the bridge tower is in a reasonable range,which is the best crossing angle.

关 键 词：大跨度悬索桥 走滑断层 地震动合成 永久位移 脉冲周期 跨断层角度 地震响应 

分 类 号：U24[交通运输工程—道路与铁道工程] U448.25[建筑科学—桥梁与隧道工程]