Time-dependent reliability analysis of B70 pre-stressed concrete sleeper subject to deterioration

Railway sleepers are amongst the vital components of the rail track superstructure and play significant role in providing integrity and safe operation of the tracks Such sleepers are manufactured with different composition among them pre-stressed concrete sleepers are more common From the durability and the track resistance point of view the sleepers that originate from the same factory posses almost the same mechanical properties However they may end up in different working conditions Similar to all other types of structures an initial reliability Index can be assigned to pre-stressed concrete sleepers in the beginning of their service life Naturally this index decreases over the time according to the environmental conditions The authors of this article have investigated the impact of penetration of chloride ion on reliability index of B70 pre-stressed concrete sleeper It is the purpose of this paper to present the correlation between the corrosion due to chloride ion and the reliability index of the concrete sleepers UIC713 code is used to provide for the loading conditions and the analysis of concrete sleepers The limit state function that is used for the pre-stressed concrete reliability analysis is based on the allowable stress criteria The simulation procedures that are used in this article are based on a computational reliability model and the Monte Carlo technique The change in the reliability Index is calculated in points with significant tensile stresses such as the top fiber of the sleeper the mid-span and the bottom fiber of the rail seat The sensitivity analyses indicate that the sleeper reliability is considerably sensitive to the variations of dimension the strength and the loading of the sleeper It is concluded that the sleeper mid-span is more vulnerable than the rail seat and the failure at this point is more likely to occur (C) 2010 Elsevier Ltd All rights reserved