The Influence of Deck Flexibility on the Dynamic Response of Railway Bridges

Abstract

A simplified methodology is proposed for railway bridge vibration analysis under train loading. Dynamic models of both train and bridge were assumed to be initially uncoupled, yet bound by contact forces. These forces were evaluated from the dynamic response of the vehicle subjected to support excitation caused by rail and wheel geometric irregularities. Such forces were statically condensed in the vehicle centre of gravity and applied to a 3D-beam finite-element model of the bridge. The influence of the rigid-deck hypothesis on the dynamic response is assessed via an iterative procedure to redefine updated “equivalent rail irregularities” as the sum of the deck displacements and the “actual” rail irregularities. The new interaction forces are re-applied to the bridge model to determine new displacements, repeating the procedure until the results converge.