高墩梁桥的地震冲撞效应及其应对策略初探

Seismic pounding effects on girder bridges with high piers and mitigating counter measures

国内外多次地震表明了高墩桥梁的地震冲撞破坏现象,针对目前国内大量兴建的高墩梁桥,有必要研究高墩梁桥地震冲撞效应和减轻桥梁地震冲撞破坏的应对策略。本文根据高烈度震区的1座高墩梁桥建立全桥的空间有限元模型,并在墩-梁结合部伸缩缝处采用非线性接触单元模拟相邻梁间的冲撞行为,同时考虑了下部支座的影响;考虑不同的强震动输入,采用非线性时程分析方法,研究了高墩梁桥的地震冲撞效应及减轻冲撞的有效措施。研究结果表明:本文采用的冲撞力学模型能够合理地模拟地震作用下结构的冲撞现象;冲撞行为对结构的地震反应影响复杂;地震动特性对冲撞效应影响显著;调整伸缩逢宽度或设置弹簧-阻尼限位装置可有效缓解结构间的冲撞效应。

The seismic pounding damage to bridges occurred under pounding effects and countermeasures for mitigating these effects is bridges with high piers are being built in China. This paper adopts pounding effects among girders and the role of isolators below. The the seismic pounding effects on bridge are analyzed under different several earthquakes, so the research on seismic needed , considering the fact that many girder a nonlinear pounding model simulating both the finite element model of a bridge is formed, and ground motions, then the countermeasures are offered and validated. The results show that the nonlinear pounding model presented in the paper can reasonably simulate the seismic pounding that has complex effects on the seismic response of bridge. It＇s also found that the characteristics of ground motions influence the pounding effects of structure markedly, and that adjusting the width of expansion joint properly can mitigate the pounding effects, which can also be abated by using spring - damper restrainers.