The Interaction of Steel Railway Bridges with Wooden Sleepers and Loaded CWR Tracks in Respect of Longitudinal Forces

Helga Papp, Nándor Liegner

Last modified: 2017-02-28


If rails are constructed continuously over discontinuities (such as between a bridge deck and an abutment) without any rail expansion devices, the rails might restrain the free movement of the bridge, therefore longitudinal forces might be generated in the rails, in the bridge structure and the fixed bridge bearings. As a result of the interaction of steel railway bridges and continuously welded rail (CWR) tracks, normal force can be generated in the rails from the deflection of the bridge deck, from braking and acceleration of the trains and from change of temperature. Internal forces and displacements resulting from the change of temperature arise on an unloaded track. Effects from the braking and acceleration of the trains are generated on a loaded track. The longitudinal behaviour of a loaded and an unloaded track is basically different, therefore a non-linear computation has to be carried out on an unloaded and another one on a loaded track. Eurocode standard allows for the linear superimposing of results obtained from two non-linear models. This paper produces calculation methods for the combined response of CWR tracks and bridges in respect of longitudinal effects, without carrying out computations on two separate non-linear models. Recommendations are presented for the calculation of internal normal forces in the rails, bridge structure and the fixed bearing, and also that for relative displacement of the bridge and the rail.


expansion joint; heat expansion; steel bridge; wooden sleepers; rail restraint; combined response

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