Investigating plastic behavior of railway bridge and running safety indices in 3D train-track-bridge interaction model under impact load applied to bottom of concrete girder

Abstract

This study investigates dynamic behavior of railway bridges subjected to lateral impact load induced by over-height vehicle while a train passes over the bridge. The lateral displacement at the bottom of the bridge girder subjected to impact load is first compared with the specified value considering the bridge elastic and plastic behavior using finite element model (FEM). Then, in the railway bridge sector, different sensitivity analyses are performed on the parameters of lateral displacement, vertical and lateral bridge deck acceleration, sleeper lateral displacement and vertical and lateral rail acceleration on the same and opposite sides of the impact load at different impact loads induced by changes in the impact velocity. In the vehicle sector, vertical and lateral forces of wheel-rail contact and lateral acceleration of the train bogie are obtained at the impact load of 8,700 kN considering the bridge plastic behavior. Finally, the results obtained from dynamic analysis of train-track-bridge interaction revealed train running safety indices exceed the allowed values specified by China Railway Regulations as the impact load exceeds 66 MN in terms of derailment factor and 4 MN in terms of offload factor. © 2025 Taylor & Francis Group, LLC.