大跨度渡槽考虑流固耦合的纵向地震响应分析

Study on Longitudinal Seismic Dynamic Response of Large-span Simply Supported Beam Aqueduct Considering FSI

以大跨度简支梁式渡槽为对象,研究其在纵向地震一致激励,以及考虑行波效应时的纵向流固耦合响应。研究表明槽墩墩顶与槽身之间的纵向错动位移值在有行波效应时明显大于激励一致的情况。因此,行波效应更容易导致渡槽纵向失稳破坏。并且槽墩墩顶与槽身之间的纵向错动位移的最不利情况都是纵向约束在高墩一侧两端支撑不等高的渡槽。因此,设计时应避免。另外,对纵向稳定最有利结构在一致激励情况下是纵向约束在矮墩一侧两端支撑不等高的渡槽结构,而在激励存在行波效应情况下是两端支撑等高的渡槽结构。

Large-span simply supported beam aqueduct is taken as the research object. Its longitudinal dynamic response considering FSI is studied, as well as, longitudinal seismic traveling wave effect and unequal height support effect. Research shows that, the longitudinal alternate displacement between the pier top and the end rib of traveling wave effect is bigger than that under uniform excitation wave, therefore, the traveling wave effect is more easily lead to longitudinal instability destruction of aqueduct. And the most unfavorable aqueduct structure of longitudinal ahemate displacement between the pier top and the end rib is the unequal height support aqueduct whose longitudinal restraint conditions located in the higher pier side, therefore, the design should be avoided. In addition, the most favorable aqueduct structure of longitudinal alternate displacement between the pier top and the end rib is the unequal height support aqueduct whose longitudinal restraint conditions located in the lower pier side under uniform excitation, and that the equal height support aqueduct under traveling wave effect.