以我国首座跨海公铁两用钢桁斜拉桥———元洪航道桥(主跨532 m)为研究对象，采用空间板梁单元法建立有限元模型，对该桥地震响应特征及阻尼器减震效果等进行了研究。结果表明：大跨度斜拉桥动力特性分析除应考虑拉索垂度效应外，也应同时考虑梁—柱效应；动力特性分析时宜优先采用多重Ritz向量法，以使振型参与质量更快达到抗震计算要求；不同地震水平下，边墩和辅助墩的墩底、主塔塔底和下横梁附近截面将承受较大弯矩，为地震易损部位；N4#塔梁间设置纵向黏滞阻尼器后，罕遇地震作用下 N3#主塔(支座纵向固定)顺桥向弯矩、结构纵向位移均明显减小，最大减幅分别达40.6%和44.8%，减震效果明显。%T he Yuanhong C hannel Bridge in Pingtan Railw ay is the first and the largest highw ay and railw ay shared cable-stayed steel bridge crossing the strait in China with the main span of 532 m. The seismic response and seismic mitigation effect of dampers of this bridge was studied based on a spatial plate-beam finite element model. Both sag effect and beam-column effect shall be considered for the analysis of the dynamic characteristics of the large-span cable-stayed bridge. Ritz method was suggested,satisfying the requirement for the faster seismic calculation. It's prone to damage at the bottom of the side and auxiliary pier,the tower's root region and its lower transverse beam under different seismic level. After installing the viscous damper in the longitudinal direction between the N4# pylon and girder,the decrease of longitudinal bending moment of the N3# pylon( with bearings fixed in longitudinal direction) and that of the longitudinal displacement were significant under rarely occurred earthquake,with the maximum decrease rate of 40. 6% and 44. 8% respectively,indicating good effect of seismic mitigation.
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