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以西南山区线路中常用的双柱式高墩桥梁为研究对象,建立典型桥跨结构的空间动力分析模型,采用非线性动力时程分析方法,详细研究了考虑地震碰撞效应时桥梁结构的地震响应特性,并探讨了接触单元刚度取值、间隙宽度、桥台刚度以及支座滑动性能等非线性边界条件的影响。结果表明:梁间碰撞作用主要发生在近桥台伸缩缝处,碰撞作用减小桥墩的地震响应,同时在梁体中产生较大的短时加速度脉冲效应;考虑桥台的纵向约束作用将使得梁间碰撞效应增强;对于通常设计采用的间隙宽度范围,强震作用时碰撞现象会不可避免地发生;支座滑动性能对桥墩的地震响应起到隔震的作用,考虑支座滑动性能后梁间碰撞次数减少;各种非线性边界条件因素的综合作用使得桥跨结构的地震响应变得较为复杂,为获得结构真实响应结果应该合理考虑这些因素的影响。
Taking the double-column high-pier bridge commonly used in the mountainous area of Southwest China as the research object, the dynamic model of the typical bridge structure is established. The nonlinear dynamic time history analysis method is used to study the seismic response of the bridge structure The influence of the nonlinear boundary conditions such as the stiffness of the contact element, the gap width, the rigidity of the abutment and the sliding behavior of the support were discussed. The results show that the collision between beams mainly occurs at the expansion joint near the abutment, the collision effect reduces the seismic response of the piers, and a large short-time acceleration pulse effect occurs in the beam body. Considering the longitudinal restraint of the abutment, And the collision effect is enhanced. For the range of gap width usually designed, the collision phenomenon will inevitably occur when the strong earthquake is acting. The sliding behavior of the bearing acts as a shock isolation for the seismic response of the bridge pier. Considering the number of collisions Reduce; the combination of various non-linear boundary conditions makes the seismic response of bridge structures more complicated, and the influence of these factors should be reasonably considered in order to obtain the true response of the structure.