车辆激励下中央扣对悬索桥梁端位移的影响

Effects of Central Buckle on End Displacement of Suspension Bridges under Vehicle Excitation

为研究中央扣对悬索桥梁端位移的影响,以洞庭湖二桥为工程背景,考虑结构几何非线性效应,建立相应的全桥空间有限元动力模型.基于有限元模型,考虑多种行车工况,研究了中央扣对该桥动力特性及在车辆激励下对梁端位移的影响.结果表明:中央扣能显著提高悬索桥的整体纵向刚度,改变悬索桥的纵飘模态特性.在车辆激励下,设置中央扣明显减小了加劲梁的纵向振幅,提高了加劲梁的振动频率,导致梁端累加位移值增大.双向行驶的车辆越多,增设中央扣后梁端位移峰值减小得越明显.不同类型的中央扣造成悬索桥对应的共振车速和主梁的动力响应各不相同.行车工况下,不同类型中央扣对梁端位移的控制效果各有差别.

In this study,the Dongting Lake Bridge II was chosen as engineering background to investigate the effects of the central buckle on the end displacement of suspension girder. Considering the geometric nonlinear effect,three finite element models of the suspension bridge were established. Based on the FE model and considering multiple driving conditions, the effect of central buckle on the dynamic characteristic of the suspension bridge and end displacement under vehicle excitation was investigated. It is shown that the central buckle can significantly increase the stiffness of the suspension bridge,and it seems to govern the longitude modal displacement at the end of the girder. Moreover, the transient analysis was performed to investigate the vehicle-induced dynamic response of the suspension bridge. Furthermore, the effects of the central buckle on the longitude modal displacement in the end of girder were evaluated. The results show that the central buckle can be designed to decrease the peak value of the dynamic response of the girder. However, it increases the cumulative displacement at the end of the girder.