大跨斜拉桥施工阶段主塔地震响应分析

Earthquake response analysis of the long span cable-stayed bridge's main tower at construction stage

为了研究大跨径斜拉桥施工阶段地震响应的影响,以四川泸州康博大桥为例,建立了有限元模型。采用反应谱法与动态时程分析法,对施工过程中各个施工阶段主塔地震响应进行了分析、对比。由反应谱分析结果可知,最大悬臂状态时主塔基频较低,处于较不利状态。由时程分析结果可知,在组合地震激励下,各个工况的塔底弯矩和塔顶位移均比相同工况时在单一方向地震激励产生的地震反应要大。该结果可为大跨斜拉桥的抗震设计与施工提供良好保证。

In order to study the seismic response of long span cable-stayed bridge at certain construction stage.The finite element model of Kangbo Bridge which is located at Luzhou city of Sichuan Province is established.Earthquake response of main tower at different construction stage during the constructing process is analyzed by the response spectrum method, and is the dynamic time history analysis method, and is compared the data with each other.According to the result of response spectrum analysis,the fundamental frequency is the lowest in the maximum cantilever state.The result of time history analysis shows that the moment of tower＇s bottom and the displacement of tower＇s top under combined-direction seismic excitation at each state are bigger than under single direction seismic excitation at the same state. A good guarantee for the span cablestayed bridge＇s seismic design and construction is provided.