高震区大跨钢-混结合梁斜拉桥纵向碰撞效应研究

摘要

Since the pounding will occur in the cable-stayed bridge and its approach bridge,the impact of collision between the main and approach girders of Xigu Yellow River Bridge is analyzed.The collision effect of towers,piers and beams are mainly discussed and the optimal design of bridge is made by the different connections between tower and beam.The results show that the pounding can significantly amplify the seismic forces acting on piers of approach span and there are little effects on the stress of tower and the displacement of beam.However,there are great influences on the pier,beam and joint of approach span which will easily cause the girder falling.The damping system can not only reduce the displacement of beam end,but also can significantly reduce the seismic response of the main tower and foundation.%针对西部山区强震作用下斜拉桥主桥与引桥间可能发生的碰撞现象,以西固黄河大桥为工程背景,对地震作用下大跨高墩钢-混结合梁斜拉桥主、引桥梁体之间的碰撞效应进行分析,重点探讨了碰撞效应下主塔、桥墩、主梁与引桥等结构的地震响应,并结合不同的塔-梁连接方式对桥梁纵向布置进行优化设计.结果表明,强震作用下主桥和引桥相邻梁之间易产生碰撞,碰撞效应对桥塔内力、主梁位移的影响不大,但对引桥桥墩内力、梁体位移以及伸缩缝处的相对位移影响较大,引桥桥墩和梁体容易发生破坏;阻尼减震体系不仅可以减小主梁梁端位移,而且可以显著减小主塔及其基础地震响应,是最合理的纵桥向抗震结构体系.