Analytical Study on Loading Capacity of Prestressed Concrete Sleeper

Abstract

In this study, analytical study is executed to evaluate loading capacity of a prestressed concrete sleeper (PC sleeper) using numerical analysis models reproducing static loading test and impact load test. Recently, demand for replacements of existing PC sleepers is increasing, and hence surveys of deteriorated PC sleepers and studies on preparation of standards for maintenance of the PC sleeper have been strongly needed. However, there were few studies that quantitatively examined the effects of various parameters, such as concrete material property, deformation of sleepers and prestressing steel bars, on the loading capacity of the PC sleepers. In the previous study, the destruction mechanism of PC sleepers due to the impact load generated by wheels and rail joint was made clear by the experiments and the dynamic linear analysis. However, evaluation of the effects of various parameters constituting the PC sleepers is limited. In this study, nonlinear static analysis is executed to identify effects of various parameters on the loading capacity of the PC sleepers. In addition, dynamic nonlinear analysis is executed to identify the effect of impact load caused by wheels and rail joints on the amplification of the response that acts on the PC sleeper. 3D finite element analysis is executed using LS-DYNA. The results of both static and dynamic analyses are able to numerically reproduce experimental results accurately. The result of the static analysis shows that loading capacity of the PC sleeper is strongly affected by the number of valid prestressing steel bar and effective prestressing force. Moreover, wear of the PC sleeper affects the loading capacity of the PC sleeper at a cross section of the middle of the sleeper. The results of the dynamic analyses performed by changing loading time and the peak load of the impact load show that cracking load is reduced compared to the result of static analysis. This is caused by the response amplified by resonance of the natural vibration mode of PC sleeper.