考虑拉索局部振动的铁路斜拉桥车桥耦合振动分析

Analysis of bridge and vehicle coupled vibrations with cable vibration

为研究拉索局部振动对大跨度铁路斜拉桥及桥上列车动力响应的影响,基于索-桥动力相互作用理论,以(60.5+156+464+156+60.5)m五跨连续钢桁梁铁路斜拉桥为工程背景,分别建立考虑斜拉索局部振动的多桁架模型(MECS)和传统的单桁架模型(SECS),采用动力分析程序BDAP V2.0,针对地铁B型车以不同车速通过该桥时的车-桥耦合振动响应进行了仿真计算。计算结果表明:考虑拉索局部振动后,出现大量纯索振型与索-梁耦合振型;桥上车辆受拉索局部振动的影响不大,但单桁架模型会高估斜拉桥塔顶的加速度响应。因此,在进行大跨斜拉桥动力响应分析时,拉索局部振动的影响不容忽视。

In order to study the influence of cable vibration on the responses of train and cable - stayed bridge system, the MECS model through considering the cable vibrations and the traditional SECS model were set up based on the cable-bridge interaction theory, respectively. As an example, a five continuous steel truss beam railway cable-stayed bridge with spans of 60.5 ＋ 156 ＋ 464 ＋ 156 ＋ 60.5m was modeled, and the responses of vehicle and bridge system under B-type subway body running over the bridge at different speeds were calculated and compared by the version 2.0 of bridge dynamic analysis program （BDAP V2.0）. The results show that a large number of single cable vibration mode and cable-beam coupled vibration mode appear after considering the cable vibration, and the cable vibration has trivial influence on the dynamic responses amplitudes of the train. If the cable vibration of the cable-bridge model are ignored, the acceleration responses of the tower on the top may be overrated. So, the cable vibration should not be ignored when the dynamic responses of long span cable - bridge are analyzed.