Experimental and numerical investigations of rail behaviour under compressive force on ballastless track systems

Aiming to verify the behaviour of ballastless track systems under high compressive rail forces occurring in the vicinity of bridge joints due to track bridge interaction, numerical and experimental studies are described in this paper. At first, a short summary of background information on the allowable rail stresses under compressive force on ballasted track systems is presented. Subsequently, a numerical pre-study for ballastless systems is performed. The unfavourable imperfection cases and loading procedures in transverse direction for experimental tests are determined. Based on these results, two rails are experimentally tested to achieve practical results. To ensure safety and reliability of the system, a specific testing program and a measurement concept are developed. Main testing results including the rail geometry, deformation and stress development are compared and discussed. Additionally, numerical models to evaluate the rail behaviour are improved and verified. A good consistency between the finite element model and the testing results could be achieved. The performed investigations give a scientific basis in order to increase the allowable rail compressive stresses in comparison with the existing values in the codes. A higher allowable rail stress considerably improves the design conditions for long railway bridges.