Research Information System
TRANSPORTATION RESEARCH BOARD 93rd Annual Meeting, Washington Dc, United States Of America, 12 - 16 January 2014, (Full Text)
Prestressed high performance concrete railroad sleepers are frequently used in ballasted high speed railways. There are strictly enforced dimensional production tolerance values for the concrete sleepers on the scale of millimeters. The creep and shrinkage of the prestressed high performance concrete sleepers within regions of low humidity have the potential to reduce their gauge lengths below their allowed tolerance values. The probability of rail abrasion, friction and derailment of a train under a given speed increases with the level of reduction of the gauge length that requires an evaluation of the time related dimensional changes of a sleeper before the finalization of its design. Ankara - Konya High Speed Railway located in Turkey is a ballasted railway that became operational in 2011. An analytical engineering evaluation that was conducted for the prestressed high strength B70 class sleepers showed that the cumulative dimensional changes of the sleepers due to the effects of prestressing, shrinkage and creep after demolding had the potential to reduce their shoulder length and the associated gauge length below the allowed tolerance within two months of their production. The sleeper molds were dimensioned to include an estimate for the time dependent contractions. The contractions of a number of sleepers produced by the adjusted molds were measured for two months, confirming the requirement to modify the production lengths of the sleepers to be used in high speed railways proposed along routes within arid climates.