Seismic response analysis and design of long-span structures must consider the spatial variation of earthquake ground motions.In this article, the seismic response of a long-span cable-stayed bridge under spatial variable ground motions is presented. An evolutionary coherency model for spatial variation of ground motions is proposed. The finite element model of the cable-stayed bridge is established and the response is analyzed.The results show that the proposed evolutionary coherency model can be used to simulate the artificial spatial variable earthquake ground motions. The damping coefficient can effectively affect the energy dissipation capacity of the viscous damper. As a result, the seismic capacity of the bridge could be enhanced by increasing the damping coefficient of the viscous damper. However, the influence of the damping coefficient on the damper energy dissipation capacity is saturated when the damping coefficient is large.%大跨度工程结构的地震响应分析和抗震设计必须考虑地震动的空间变化效应.以大跨斜拉桥为工程背景,提出了一个空间变化地震动的时变相干函数模型,利用谱表现方法对地震动位移时程进行了模拟.建立了斜拉桥的有限单元模型,计算了其在非平稳空间变化地震作用下的响应.结果表明:提出的时变相干函数模型能够用于各向异性空间变化地震动的样本模拟;提高阻尼系数能够有效增强阻尼器耗能能力,进而增强结构抗震能力,但阻尼系数对阻尼器耗能能力的影响会出现饱和现象.
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