变速移动荷载作用下简支梁桥的动力响应及共振分析

基于振型叠加原理,采用广义坐标变换的方式建立了移动荷载匀变速通过简支梁桥时系统的动力平衡微分方程并编写了分析程序。以某3×32 m铁路多跨简支箱梁桥为例,计算得到车辆匀速运行时桥梁最大挠度随车速的变化曲线,选取曲线上的代表值点进一步计算,并从车桥共振的角度详细分析了桥梁最大挠度的变化趋势以及车辆变速运行对桥梁最大挠度的影响。

Dynamic response and resonance analyses for a simply-supported bridge under speed-varying loads

Based on modal superposition technique, the dynamic equations of a coupled vehicle-bridge system were established with generalized coordinates and the vehicle load passing the bridge with varying speed, and a computer code was worked out. The proposed method was then applied to the analysis of a railway bridge with 3 x 32 m multi-span sim-ply-supported box-girders. The distribution curve of the bridge maximum deflection versus vehicle speed was drawn basedon the calculated data. To study the influence of the speed variation on the bridge deflection, a further calculation was performed on some selected typical points of the curve. The influences of speed - varying loads on the peak bridge deflec-tions and their varying tendency were explained in detail with the vehicle-bridge system resonance mechanism.