Optimal design and analysis of pre-stressed concrete sleepers
The track system consists of structural components like a sleeper that has to be designed to accommodate the maximum tonnage. The main function of a sleeper is to transfer the load from the rail to the ballast via the rail pad and to the under laid formation. The analysis and design of concrete sleepers requires the assessment of load on the sleepers, ballast pressure distribution, selection of the dimensions of the sleeper and moment calculations at critical sections. In this paper a pre-stressed pre-tensioned concrete sleeper having an optimal shape, strength and tendon type and profile with reference to the existing sleeper type that is used by the Ethiopian Railways Corporation (ERC), which is the new type II Chinese sleeper, was analyzed and designed. Moreover, FEM modeling of pre-stressed concrete sleepers was conducted. The optimal design output of this research shows that increasing the concrete grade results an increase in sleeper capacity but has no more effect on moment capacity which is largely dependent on the section dimension of the sleeper, tendon strength and eccentricity. The final optimized design outputs and analysis result of the existing sleepers are compared with respect to raw material consumption for production and its capacity.
Keywords: Analysis, design, sleeper, FEM modeling, optimization, pre-stressed concrete