采用集中质量模型的大跨度斜拉桥桩–土–结构动力相互作用研究

Research on Pile-Soil-Structure Dynamic Interaction of Large Span Cable-Stayed Bridge by Using Lumped Mass Model

摘要: 为研究桩–土–结构动力相互作用对大跨度斜拉桥地震响应的影响，以主跨700 m的江顺大桥为背景进行抗震分析。运用m法、粘弹性人工边界法以及辐射阻尼理论给出了集中质量模型的关键动力参数确定方法，采用Midas Civil建立全桥数值模型，分析桩–土–结构动力相互作用对斜拉桥结构地震响应的影响规律。研究表明：不论是纵向地震还是横向地震作用，集中质量模型的桩基内力响应在三种模型中是最小的，且桩顶内力响应值比工程简化模型最高可小30%左右；集中质量模型偏小的主要原因是地震波向无限远地基传播在散射过程中产生辐射阻尼所致。

Abstract: In order to study the influence of pile-soil-structure dynamic interaction on seismic response about the long-span cable-stayed bridge, the seismic analysis is carried out in the background of Jiangshun Bridge of main span 700 m. The key dynamic parameters of concentrated mass model are given by M method, viscoelastic artificial boundary method and radiation damping theory. The numerical model is established by Midas/Civil, and the dynamic interaction influence law on ca-ble-stayed bridge is analyzed .Research shows that: regardless of the vertical earthquake and ho-rizontal earthquake action, the pile internal force response of the concentrated mass model is the smallest in three kinds of model, moreover, the pile top force response value is 30% smaller than that of engineering simplified model. The main reason is due to radiation damping which produces in the scattering of seismic waves propagating in infinite foundation.