Dynamic modeling of train and bridge with stepped-beam cross-sections

Abstract

Railway systems are critical in many regions and facilitate large volume of freight movement cost-effectively. In North America, the majority of railway bridges were built at the beginning of the twentieth century. With the recent increase of railcar weight limits from 1170 kN to 1272 kN, concerns are raised regarding the condition and dynamic behavior of these bridges. This study focuses on the dynamic response of stepped beam under moving trains. The train is composed of a certain number of railcars, and each railcar is consisted of oscillators with three masses representing the railcar body, bogie and wheel sets, respectively. The connects among components is simulated by spring and dashpot units. Meanwhile, finite element method with Euler-Bernoulli beam element is used to model the stepped beam with variational sections. The contact force between the wheel and rail is simulated by the Hertzian spring. The interaction of train-bridge system is assumed to be nonlinear and is solved by an iterative algorithm. At last the developed model is verified using the data from field testing.