辅助墩对大跨斜拉桥在地震作用下的影响——以禹门口黄河公路大跨斜拉桥为例

斜拉桥属于高次超静定柔性结构,辅助墩的设置会改变其结构的受力和变形,对塔顶位移、塔根弯矩、主梁挠度和弯矩等均有一定的影响.为了研究辅助墩的设置数量对大跨度斜拉桥地震响应的具体影响规律,依托陕西禹门口黄河公路大桥工程,采用数值分析的方法,用有限元分析软件CSiBridge对该斜拉桥建立3种方案的有限元模型,即无辅助墩方案、一个辅助墩方案、两个辅助墩方案.在3种方案下利用动力反应谱分析法和时程分析法进行地震作用下的主塔及主梁关键截面内力及线形分析,得到在不同方案下的变化特点.综合两种方法分析结果,辅助墩的设置会增加该类桥型的塔底和主梁弯矩,但对主梁位移有所改善,可见辅助墩的设置对该类型桥梁地震响应的影响有利有弊.

The influence of auxiliary pier on long span cable-stayed bridge under earthquake action

The cable-stayed bridge belongs to high-order statically indeterminate flexible structure, and the setting of auxiliary piers will change the stress and deformation of the structure, and have certain influences on the tower top displacement, the root moment, the deflection and moment of the main girder. In order to study the influence of the number of auxiliary piers on the seismic response of long-span cable-stayed bridge, this paper relies on the Yellow River Highway Bridge project of Shan^,xi Province, and uses the finite element analysis software CSiBridge to establish three kinds of finite element models of the cable-stayed bridge, namely, no auxiliary pier scheme, one auxiliary pier scheme and two auxiliary pier scheme. The dynamic response spectrum analysis method and time history analysis method are used to analyze the internal force and alignment of the key sections of the main tower and girder under earthquake action. The variation characteristics under different schemes are obtained. Combining the analysis results of the two methods: the setting of auxiliary piers will increase the tower bottom and main beam bending moment of this type of bridge, but improve the main beam displacement, so it can be seen that the setting of auxiliary piers has both advantages and disadvantages on the seismic response of this type of bridge.