不同地震激励下大跨度跨海斜拉桥地震响应与减震效应研究  

Research on seismic response and seismic reduction effect of large-span cable-stayed bridges under different seismic excitations

作　　者：张滨洋 李艺林 Zhang Bin-yang;Li Yi-lin(China Road&Bridge Corporation,Beijing 100011,China)

机构地区：[1]中国路桥工程有限责任公司,北京100011

出　　处：《工程抗震与加固改造》2024年第5期131-140,共10页Earthquake Resistant Engineering and Retrofitting

摘　　要：为探究不同地震激励下大跨度跨海斜拉桥地震响应与减震效应,首先基于有限元软件建立某跨海大桥三维空间有限元模型,并给出了桥梁的结构自振特性;其次基于桥址处的场地条件选取了多种类型的地震动,作为后续动力响应分析的地震动;最后基于非线性时程分析法,研究了多种复杂地震作用下的结构动力响应,并对阻尼参数进行研究,探究该斜拉桥的阻尼器减震方案。研究表明:纵向+竖向地震下的桥塔内力最大,剪力和弯矩最大分别为2.46×10^(4)kN和4.53×10^(5)kN·m;越靠近边索,拉索轴力和应力越大;脉冲地震下的主梁跨中竖向位移振幅最大,约为0.8m,而主梁纵向、塔顶纵向位移相对较小,最大约为199.076mm;当桥塔处采用的液体黏滞阻尼器参数均为α=0.3、C=6000时,可以达到最优的减震效果。相较于无阻尼器状态,塔底弯矩减小了31.8%~42.7%,塔底剪力减小了8.8%~13.5%,塔顶位移减小了39.8%~41.9%。To investigate the seismic response and seismic reduction effects of large-span cable-stayed bridges under different seismic excitations,a three-dimensional finite element model of a sea-crossing bridge was first established based on finite element software,and the structural natural vibration characteristics of the bridge were presented.Secondly,based on the site conditions at the bridge site,various types of ground motions were selected as the ground motions for subsequent dynamic response analysis.Finally,based on the nonlinear time history analysis method,the dynamic response of the structure under various complex seismic actions was studied,and the damping parameters were studied to explore the damper damping scheme of the cable-stayed bridge.Research shows that internal forces of the bridge tower under longitudinal and vertical earthquakes reach maximum,and the maximum shear force and bending moment are 2.46×10^(4)kN and 4.53×10^(5)kN·m,respectively.The closer it is to the side cable,the greater the axial force and stress of the cable are.The maximum vertical displacement amplitude of the main beam in the mid span under pulse earthquakes is about 0.8m,while the longitudinal displacement of the main beam and tower top is relatively small,with a maximum of about 199.076mm.When the parameters of the liquid viscous damper used at the bridge tower areα=0.3 and C=6000,the optimal shock absorption effect can be achieved.Compared to the state without dampers,the bending moment at the bottom of the tower is reduced by 31.8%~42.7%,the shear force at the bottom of the tower is reduced by 8.8%~13.5%,and the displacement at the top of the tower is reduced by 39.8%~41.9%.

关 键 词：跨海大桥 近断层脉冲地震 结构动力响应 非线性时程 减震分析 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]