福厦高铁无支座整体式刚构桥地震响应研究

Study of Seismic Response of Integral Rigid-Frame Bridge on Fuzhou-Xiamen High-Speed Railway Bridge

为了解高速铁路无支座整体式刚构桥的抗震性能,以福厦高铁泉州湾跨海大桥海上深水区(3×70)m无支座整体式刚构桥为背景,通过有限元模型分析该桥在多遇地震、设计地震和罕遇地震下的地震响应;采用增量动力分析方法,对梁端的碰撞概率进行研究。结果表明:大桥满足铁路三水准抗震设防要求;在顺桥向地震作用下,边墩比中墩更控制设计,边墩墩顶最容易进入弹塑性状态;在横桥向地震作用下,中墩比边墩更控制设计,中墩墩底较墩顶受力更不利;地震下伸缩缝的需求值较大,相邻梁端发生碰撞的概率较大,需增加阻尼器防止梁端碰撞。

To examine the seismic performance of integral rigid-frame bridges on high-speed railway,the integral rigid-frame bridge with spans of 3×70 m in deep water area,which is part of the Quanzhou Bay Sea-crossing Bridge on Fuzhou-Xiamen High-speed Railway,is cited as a case.The finite element model of the rigid-frame bridge was established to analyze the seismic responses of the bridge under frequent earthquakes,design earthquakes and rare earthquakes.The girder-end collision probability was evaluated by using the incremental dynamic analysis method.The results indicate that the bridge meets the seismic fortification requirements of the three types of earthquakes.Under the seismic energy along the bridge length,the function of side piers is more critical than the central piers,and the tops of the side piers are prone to be in plastic state.However,under the seismic energy along the bridge width,central piers dominate the design,with pier base in more unfavorable state than the top.In the seismic event,the expansion joint needs greater moving capacity,which will increase the collision probability of adjacent girders,hence,dampers should be added to prevent the potential girder-end collision.