桥墩形式对曲线形连续刚构桥地震响应的影响

The influence of pier types on the seismic response of the curved continuous rigid frame bridge

以西牛大桥为工程背景,将主墩分别设计为单柱式薄壁墩、双柱式薄壁墩和组合式墩柱3种形式,运用Midas/Civil软件对高墩大跨曲线形连续刚构桥进行三维地震动态时程分析,比较不同的桥墩形式以及曲率半径对高墩大跨曲线形连续刚构桥抗震性能的影响。分析结果表明,在主梁弯矩分配上,双肢墩和组合墩要优于单肢墩,而在主梁位移与墩顶轴力方面,组合墩也具有明显的优势;在桥墩形式不变的情况下,随着曲率半径的增大,主梁跨中弯矩和竖向位移先出现明显的减小,之后趋于平缓。

Regarded Xiniu Bridge as the background,the main piers were designed to be single-column thin-wall piers,double column type thin-wall piers and combined type piers respectively.Using Midas/Civil,this paper made a three-dimensional seismic time-history analysis for high-piers long-span curved continuous rigid frame bridge,compared and analyzed the seismic performances in different pier types and curvature radius.The results show that,in girder bending moment distribution,the bridge in double column type performed better than combined type.As to girder displacement and axial force in pier-top,the combined type had an obvious advantage.When the curvature radius grow in a certain pier type,the bending moment and vertical displacement in midspan decrease evidently at first,then become flat.