布索形式对斜拉桥抗震性能的影响

Influence of cable arrangement styles on the seismic performance of cable-stayed bridge

从斜拉桥抗震概念设计的角度出发,对竖琴形、扇形和辐射形三种不同索面布置形式的斜拉桥进行了建模,并对此三种不同模型的动力特性、顺桥向时程响应进行了对比分析.研究结果表明:纵飘振型对斜拉桥的地震响应尤其是塔顶、跨中的位移响应有显著的影响;而斜拉索的顺桥向布置形式对斜拉桥的纵飘周期影响显著,随着主梁与斜拉索平均倾角的减小,纵向刚度逐渐增大,从而纵飘频率增大;索型不同,地震作用下最危险拉索的位置不同.

Three different kinds of cable planes including the harp-shape,fan-shape and radial-shape,cable-stayed bridge models are established and the comparative analysis of dynamic characteristics and longitudinal time history responses for the three different models are made.The research results show that the longitudinal seismic response of large span cable-stayed bridge is mainly determined by longitudinal floating vibration mode which plays a decisive role on the displacements of mid-span and tower top,and the arrangement types of cable in the longitudinal have distinctive influence on the period of longitudinal floating vibration mode.In general,with the decreasing of average angle between girder and cables,the longitudinal stiffness increases and the period of longitudinal floating vibration mode decreases.And with the change of cable type,the maximum of cable axial force is quite different.