不同地震激励方向的曲线连续刚构桥动力响应分析

Dynamic Response Analysis of Curved Continuous Rigid Frame Bridge under Seismic Excitation in Different Directions

为研究不同地震激励方向对多跨曲线连续刚构桥抗震性能的影响,采用MIDAS/Civil软件建立某连续刚构桥有限元模型,采用反应谱法,分析不同地震激励方向的曲线连续刚构桥的动力响应。结果表明:高墩多跨曲线连续刚构桥的最不利地震输入方向并不是横桥向和纵桥向。在地震激励角度增加到桥梁各个控制截面的切线方向条件下,顺桥向位移达到峰值;增加到法线方向附近时横桥向位移最大,而竖向位移值则不受到影响。多跨曲线刚构桥进行抗震设计时应该进行多方向激励,在对比分析基础上确定出最不利地震激励方向。

In order to analyze the influences of different seismic excitation directions on the seismic performance of multi-span curved continuous rigid frame bridges, the finite element model of a continuous rigid frame bridge was established by Midas Civil. The dynamic response of curved continuous rigid frame bridges with different seismic excitation directions was analyzed by response spectrum method. The results show that the most disadvantageous seismic excitation direction of multi-span curved continuous rigid frame bridge with high piers is not the transverse and longitudinal directions. With the increasing of the seismic excitation angle, the maximum displacement along the bridge is obtained when the angle reaches the tangent direction of each control section of the bridge. The peak value of the transverse displacement is reached when the angle reaches the normal direction, and the vertical displacement is independent of the seismic excitation angle. The multi-span curved rigid frame bridge needs multi-directional excitation in practical engineering seismic design to determine the most disadvantageous seismic excitation direction.