锚栓限位与邻梁碰撞对曲线桥梁抗震性能的影响

Influences of displacement limitation of anchor bolt and adjacent beam collision on aseismic performance of a curved bridge

曲线桥梁在地震作用下梁体之间会发生非均匀碰撞,可能造成前梁落梁或后梁局部破坏现象;而在纵向设置抗震锚栓可有效防止落梁,也可对相邻梁的碰撞起到一定缓解作用;但目前国内外还缺乏锚栓对曲线桥梁的抗震性能影响的相关研究。以某四跨曲线桥为背景工程,建立了空间有限元模型,并分别用滞后系统、钩单元、接触单元模拟了支座损伤、锚栓约束、相邻梁纵向碰撞等物理现象,利用非线性时程分析法,进行了三种工况((1)无锚栓、不计碰撞,(2)无锚栓、计碰撞,(3)有锚栓、计碰撞)曲线桥梁的墩梁相对位移、墩底内力、相邻梁碰撞力等关键地震响应对比研究。研究表明:相邻梁的非均匀碰撞是曲线桥梁必须考虑的关键因素;而设置抗震锚栓能缓解曲线桥梁的碰撞效应,并减轻震害。

Non-uniform collisions happen among girders of curved bridges under seismic action to cause girder falling of front beams or local failure of back beams.Aseismic anchor bolts set in the longitudinal direction can effectively prevent girder falling and also have a mitigative effect on adjacent beam collision.Taking a 4-span curved bridge as an example,here its spatial finite element model was built.The time-delay system,hook element,contact element were used to simulate bearing damage,anchor bolt constraints,adjacent beam longitudinal collision.With the nonlinear time history analysis method,the comparatively studying relative displacements between pier and beam,internal force of pier bottom and adjacent beam collision force under three conditions including no anchor bolt and regardless of collision,no anchor bolt and considering collision and considering anchor bolt and collision was performed.The results showed that the adjacent beam non-uniform collision is the key factor that must be considered in a curved bridge;seeting aseismic anchor bolt can alleviate collision effects of a curved bridge and has a significant action for reducing seismic damage.