近、远场地震动作用下斜拉桥动力响应分析

Analysis on Dynamic Response Cable-stayed Bridges under Action of Near-field and Far-field Ground Motions

摘要:

为研究近、远场不同类型地震动对斜拉桥动力响应的影响规律，以东南沿海某斜拉桥为研究对象，基于SAP2000软件建立了斜拉桥全桥非线性有限元模型，计算分析了近场脉冲、近场非脉冲和远场地震动三种不同类型地震下斜拉桥的动力响应。研究结果表明：当地震动强度为0.4g时，近场非脉冲地震动作用下斜拉桥墩底弯矩的响应值要大于远场地震动以及近场脉冲地震动下的响应；随着地震动强度的增加，脉冲效应对斜拉桥的动力响应的影响越大；近场脉冲型地震动对斜拉桥位移响应的影响要大于内力响应，且对塔顶位移的影响最大。研究成果对于近场区斜拉桥的抗震设计具有指导意义。

Abstract:

In order to study the influence of different near-field and far-field ground motions on the dynamic response of cable-stayed bridge, taking a cable-stayed bridge along the southeast coast as the research object, and based on SAP2000 software, a nonlinear finite element model of the whole bridge is established. The dynamic responses of cable-stayed bridge under three different ground motions of near-field pulse, near-field non-pulse and far-field ground motions are calculated and analyzed. The research result shows that when the local seismic intensity is 0.4g, the response value of pier bottom bending moment of the cable-stayed bridge under the action of near-field non-pulse ground motion is larger than the responses under the far-field and near-field pulse ground motions. As the intensity of the ground motion increases, the influence of pulse effects on the dynamic response of the cable-stayed bridge is greater. The effect of near-field pulse ground motion on the displacement response of cable-stayed bridge is larger than the internal force response, and the effect on the displacement of pylon top is the largest. The research results have the guiding significance for the seismic design of cable-stayed bridges in the near-field area.