Behaviour of pre-stressed high strength concrete sleepers subjected to dynamic loads

As part of ballasted railway track, pre-stressed concrete sleepers (PCSs) play an essential role in track response, performance and safety. PCSs are subjected to dynamic loads which are often high magnitude and low duration. The characteristics of dynamic loads, the interactions between track components and the dynamic responses of PCSs under dynamic loads have been vastly investigated throughout past decades and continue to be a subject of interest to the railway industry.. Mechanical behaviours of PCSs such as dynamic response and failure mechanisms are important to meet the structural and durability requirements of railway sleepers. However, the influence of high performance concrete (HPC) mechanical properties on behaviour of PCSs is currently lacking. This paper presents a finite element model developed as a part of a broader investigation undertaken at the University of Melbourne. Finite element modelling package LS-DYNA has been used to represent a sleeper in a simulated track condition. The model is validated based on published experimental information. Different grades of high strength concrete (HSC) have been investigated. Mechanical properties such as compressive strength, tensile strengths, fracture energy and elastic modulus are considered.. The results show that the using higher concrete grade in sleeper leads to a larger bending moment under the same dynamic load. This confirms the inadequacy of current design approach for PCSs