考虑梁端碰撞效应的单跨非对称悬索桥地震响应分析

Analysis of Seismic Response of Single-span Asymmetric Suspension Bridge Incorporating Beam-end Collision Effects

目的 研究主引桥伸缩缝处碰撞效应对大跨度悬索桥地震响应的影响。方法 以西南地区某单跨非对称悬索桥为研究对象,基于ANSYS有限元软件建立主引桥模型,采取接触单元法,研究桥梁在考虑梁端碰撞效应下的地震响应,并探究了伸缩缝间隙、碰撞单元刚度以及主引桥周期比对其影响规律。结果 主引桥间的相互碰撞会在梁端产生一个较大的碰撞力,其峰值会随着伸缩缝间隙的增大而减小,随着碰撞单元刚度的增加而增大;同时,碰撞作用使加劲梁的位移随着间隙宽度的增大而增大,随着碰撞单元刚度的增加先减小后趋于稳定,随着周期比的增大而减小;结构产生的碰撞力峰值根据地震波不同表现出不同的变化规律;塔顶位移和塔底内力基本不受参数变化的影响。结论 伸缩缝间隙和碰撞单元刚度是影响地震响应的重要参数,需要在设计中合理考虑和选择。

To study the impact of the impact effect At the expansion influence on Seismic response of large span bridge.suspension bridges,and the results can provide reference for similar bridges to resist earthquakes.Taking a single-span asymmetrical suspension bridge in Southwest China as the research object,the main approach bridge model was established based on the FEM of ANSYS,three suitable seismic waves were selected,and the contact element method was used.Used to simulate the bridge collision,and the seismic response of the bridge considering the beam end collision effect was studied,and explored the effect of changing the period ratio of the main approach bridge on the expansion joint clearance,the stiffness of the collision unit and the weight of the upper structure of the approach bridge.The mutual collision between the main approach bridges will generate a large collision force at the beam end,and its peak value will decrease with the increase of the expansion joint gap,and increase with the increase of the collision unit stiffness;at the same time,the collision As a result,the displacement of the stiffened beam increases as the gap width increases,and then becomes steady as the rigidity of the impact element increases,and decreases with the increasing of the cycle ratio.the peak value of the collision force generated by the structure is according to different seismic waves show different changing laws;the displacement of the tower top and the internal force of the tower bottom are basically not affected by the change of parameters.The changes of various parameters make the seismic response of the bridge more complicated,and the changes of these parameters should be considered reasonably in the aseismic design.