Dynamic Analysis of Railway Bridges under High-Speed Trains Action

Abstract

Train passage over bridge structure creates a non-linear coupled dynamic problem called bridge-vehicle interaction. This phenomenon can be simplified to a moving load problem, but this simplification may be unsuitable for high-speed train cases. This paper introduces two solution schemes for the interaction problem in a finite element numerical domain. The first scheme considers one whole system that includes the two interacting systems and updates its stiffness matrix dynamically according to train wheels position on bridge, meanwhile the second scheme considers two decoupled systems and calculates the transferred forces at points of contact with constraint equations. 2D beam elements of Bernoulli type are used for bridge modeling and the track is modeled as a single continuous elastic layer with irregularities. The moving train system is considered as separate moving axles and each moving axle has two degrees of freedom (DOFs) and consists of a lumped mass which is supported by a spring-damper unit. A parametric study is conducted at speeds ranging from 90 to 504 km/hr to assess the response. The moving load model and interaction models are shown to give similar response apart from resonance speeds for which the moving load model gives very high values and higher resonance speeds.