The Effect of Rubber Pads on The Stress Distribution for Concrete Railway Sleepers

A railway track system is comprised of several components such as rail, sleeper and ballast. Ballast is the weakest component in the track system and it is subjected to latent dynamic shifting. Constant and continuous loads lead to wear and breaking up of the ballast, thus, diminish the quality of track geometry. This causes unaccounted periodical tamping of track bed. A holistic solution to slow down this process is by installing rubber sleeper pads. Numerical investigation is performed using the general-purpose finite element software ABAQUS for the track system with varying rubber pad thickness and locality. The elastic properties of rubber are expected to lengthen the bending line of the rails and reduce the direct dynamic load on the ballast. Four separate models of the same load, sleeper and rail but with different rubber pad thicknesses is modelled using the finite element software ABAQUS to investigate the effect of the variation of rubber pad thickness in terms of the static stress distribution of the rail-sleeper. Spring supports are used at the bottom of the sleeper to represent the elastic stiffness of ballast bed and subgrade. The results indicate a reduction of sleeper stress along the depth of the cross-section of the concrete sleeper against increased thickness of rubber sleeper pad. Sleeper pad with 10mm exhibit a stress value of 2737kPa, whereas a stress reduction of approximately 10% and 17% was obtained if a 15mm and 20mm sleeper pad was used respectively. Nevertheless, the author concluded that the economics of using rubber sleeper pads is in the range between 22mm to 25mm. The suggested range was derived from the optimizing the behaviour of stress for both the concrete sleeper and rubber sleeper pads. The sleeper pads have the tendency to minimise excessive stress from developing within naked concrete sleepers. (paper)