Transition zones to railway bridges: Track measurements and numerical modelling

Abstract Railway tracks degrade faster at transition zones to railway bridges. In modern lines, backfills with bound and unbound granular geomaterials have been used to minimize this problem. To provide insight into the behaviour of the train–track system and to fill the gap between numerical and experimental studies, the authors carried out extensive field measurements. These were then used to validate a FEM model that considers the relevant track components, earthworks and bridge; accounts for the train–track interaction using contact elements; and is very accurate in reproducing the measurements. Results showed that the backfill design fulfils its purpose in that it provides a stiffness transition from the embankment to the bridge. The dynamic component of the train–track interaction remained low. The performance of the model makes it a very useful tool to further study the railway track at critical locations, such as transition zones.