Dynamic Stability of a Girder Under Traveling Load Mass Systems

When a multi-vehicle train passes over a railway bridge, it may be expected that a parametrically excited vibration occurs in the girders, due to the change in the additional mass distribution caused by the unsprung mass of the vehicles. An analytical method to determine the dynamic stability of thin-walled beams under a sequence of equidistant masses traveling at a constant speed is developed in this paper. In the numerical examples, it is shown that the magnitude of the unsprung mass of vehicles, the distance between them and the speed of the vehicles have a large effect on the parametrically excited unstable vibration of girders. The dynamic stability of a simply supported railway bridge is clarified using the above method.