脉冲型地震作用下独塔自锚式悬索桥碰撞响应试验研究

为了研究脉冲型地震作用下考虑碰撞效应时自锚式悬索桥的地震响应，以某独塔自锚式悬索桥为原型，设计制作了缩尺比为1:20的试验模型，并选取三条具有不同脉冲周期的近断层脉冲型地震波，利用多子台地震模拟振动台台阵系统，进行了一致激励及行波激励下的对比试验。结果表明：一致激励下梁端碰撞效应会显著增加边墩墩底变形，但会不同程度降低支座的位移响应，且碰撞效应随碰撞间隙的增加先增强后减弱；行波激励会加剧梁端碰撞作用，使碰撞效应对边墩墩底变形和主塔塔底变形的放大作用更显著；脉冲型地震动的脉冲周期与悬索桥基本周期越接近，碰撞效应越强，对边墩墩底变形及主塔塔底变形的放大效应越显著，但对支座位移降低程度的影响不明显。因此，对自锚式悬索桥进行抗震或减震设计时应当考虑碰撞效应、行波效应及地震动脉冲特性的影响。本文研究成果可为桥梁结构的碰撞响应研究提供一定的参考价值。
Abstract：In order to explore the seismic response of a self-anchored suspension bridge when considering the collision effect under the action of pulse-like ground motions,a self-anchored suspension bridge with single tower was taken as a prototype to design the test model with a reduced scale of 1∶20,and three near-fault pulse seismic waves of different pulse periods were selected to perform comparative tests under uniform excitation and traveling wave excitation on a multiple-earthquake-simulation-shake-table system.According to the test results,the collision effect has significantly aggrandized the deformation of side pier bottom but reduces the displacement response of the support in varying degrees; the collision effect at ends of the model bridge first heightens and then recedes as collision gap widens while the traveling wave excitation has intensified collision at bridge ends so that the collision effect significantly amplifies the deformation of side pier bottom and deformation of main tower bottom; the closer the pulse period of pulse-like ground motions is to the basic cycle of model bridge girder,the more intense the collision effect and the more significant amplifying effect on the deformation of side pier bottom and main tower bottom,but less effect on the reduction of support displacement.Therefore,factors such as collision effect,traveling wave effect and pulse characteristics of ground motions should be considered at seismic or aseismic design of a self-anchored suspension bridge.The findings will provide references for studying bridge structure collision response.