拱肋内倾角对钢管混凝土提篮拱桥车桥动力响应的影响

Influence of leaning angle on train-bridge coupling vibration of concrete filled steel tube arch bridge

为考虑拱肋内倾角对大跨度钢管混凝土拱桥的动力特性及车辆走形性的影响,以某主跨为240 m的钢管混凝土提篮拱桥为例,运用结构动力学以及有限元原理,分别建立了3种不同内倾角度(7.5°,8.5°,9.5°)下的桥梁动力分析模型和车辆模型,由动力学势能不变值原理"与形成矩阵的"对号入座"法则建立空间振动方程,并对3种情况下的车桥耦合空间响应进行了计算分析。研究结果表明:桥梁横向自振频率随拱肋内倾角的增加而明显增大;竖向自振振动频率随内倾角度的增大而减小;列车通过桥梁时,不同内倾角度下拱顶竖向位移和加速度的变化很小,而横向位移、横向加速度均随着内倾角度的增大而减小;车辆的动力响应对内倾角的变化不敏感。

In order to investigate the influence of leaning angle of rib on the dynamic property and train running performance of big span concrete filled steel tube arch bridge, a bridge of such type with a main span of 220 m was cited as an example. By using structural dynamics and finite element theory, the finite element models for the bridge having three kinds of leaning angle（7.5° ,8.5°,9.5°） as well as train model were respectively built. Based on the principle of total potential energy with stationary value in elastic system and the ＂set in right posi- tion＂ rule for formulating system matrixes, the bridge system spatial vibration equations were derived. By using computer simulation method, the bridge dynamic response and train running performance were calculated and an- alyzed when trains run through the bridge. The results show that the lateral vibration frequency of bridge signifi- cantly increases while the vertical vibration frequency slightly decreases with the increase of the leaning angle. The vertical displacement and acceleration of bridge under three different leaning angles essentially unchanged while the lateral displacement and acceleration increase with the increase of the leaning angle. The train respon ses are not sensitive to the change of leaning angle.