中文摘要：

研究目的：随着列车速度不断提高,对既有线上钢桁梁进行动力分析,对于正确地进行铁路桥梁的设计以及既有线路的维修加固有重要的参考意义。研究结论：将列车——钢桁梁桥视为一个整体系统,由弹性系统动力学总势能不变值原理及形成矩阵的对号入座法则,导出了车桥系统的振动方程,此法比一般的有限元法更方便。计算了DF4机车牵引25辆C62货车和DF11机车牵引18辆客车以不同的速度通过某简支钢桁梁桥的振动响应。通过分析,其行车安全有保障,舒适度指标和车辆平稳性指标均达到合格以上。说明该桥具有足够的横、竖向刚度。

英文摘要：

Research purposes：With the continuous speed-raise of train,the analysis of the dynamic response of steel truss bridge of the existing railway line has reference significance to accurate evaluation of design of railway bridge and also to maintenance and reinforcement of the existing railway line.Research conclusions：Regarding train and bridge as one composite system,by means of the principle of total potential energy with stationary value in elastic system dynamics and the ＂set-in-right-position＂rule for structural matrices,the vibration equations of vehicle-bridge time varying system are established.This method is more convenient than the finite elements.The vibration responses of a simply-supported truss bridge are calculated when DF4 locomotive hauling 25 C62 freight wagons and DF11 locomotive hauling 18 passenger coaches to pass this bridge at the different speeds.It can be seen from the analysis that the traffic safety is guaranteed and the comfortableness and stability of train reach at the standards.It shows that the bridge has sufficient lateral and vertical stiffness.