大跨度叠合梁斜拉桥多维多点非平稳随机地震响应分析

为研究地震动非平稳特性对大跨度叠合梁斜拉桥随机地震响应的影响，采用绝对位移求解的虚拟激励法在通用有限元软件中对某座叠合梁斜拉桥进行多维多点非平稳随机地震响应分析.研究结果表明:采用绝对位移求解的虚拟激励法，能在通用有限元软件中高效地实现对大跨度叠合梁斜拉桥多维多点非平稳随机地震响应分析；设计中假定地震动平稳性，得到的结果偏于保守；行波效应对大跨度叠合梁斜拉桥结构响应有显著影响，考虑行波效应对主塔塔顶位移和塔底内力是有利的，但应注意其对主梁跨中位移和内力的不利影响.

Non-Stationary Random Seismic Analysis of Large-Span Composite Beam Cable-Stayed Bridges Under Multi-Support and Multi-Dimentional Earthquake Excitations

To investigate the influences of non-stationary earthquake excitations on the random seismic responses of composite beam cable-stayed bridges, the non-stationary random seismic responses of a composite beam cable-stayed bridge were analyzed with the multi-dimensional and multi-support pseudo excitation method to directly solve the absolute displacements by means of general FEM software. The results demonstrate that the non-stationary random seismic responses of the composite beam cable-stayed bridge under multi-support and multi-dimentional earthquake excitations can be calculated efficiently with the pseudo-excitation method based on the absolute displacement solution. The stationary assumption for the structural design will usually lead to conservative results. The traveling wave effects are significant for the responses of the large-span composite beam cable-stayed bridge and will be favorable to the displacement at the tower top and the internal force at the tower bottom, instead will be adverse to the displacement and the internal force at the main beam centre.