The Fatigue Property Influence Study On Non-uniform Tension Of Type Ⅲa Concrete Sleeper

With the development of railway transportation system, the applied amount ofprestressed concrete sleeper are soaring. Concrete sleeper is important force supportelement in the rail rapid transit under train running load. During the train runtime,prestressed concrete sleepers likely to occur cracking phenomenon which can reduce thecarrying capacity. The non-uniform tensioned prestressed concrete sleepers exist duringthe stretching process, which can reduce concrete sleeper bearing capacity and service life.The fatigue property of type-Ⅲ a prestressed reinforced concrete sleeper was studied.First, type-Ⅲa prestressed reinforced concrete sleeper was site tested, the distributionof the non-uniform tension was made clear, and the reason why the spiral rib steel wasnon-uniformity tension was analyzed.Second, the selection of finite element analysis model’s unit type as well as thedivision of the element mesh and the rationality of the constitutive relations andparameter’s value were introduced based on the distribution of the non-uniform tensionand the finite element software ANSYS. The main vibration modes under dynamic loadingof the sleeper were identified by modal analysis. The effect of spiral rib steel’snon-uniformity tension on sleeps’ dynamic characteristics was analyzed, and it laid thefoundation for the numerical simulation of fatigue performance.Last, the impact of tensile force’s non-uniform distribution on the sleeps’ fatigueresistance is discussed. Especially the impact of local stress’s concentration phenomenonwhich appears at the ends of prestessed concrete sleepers on the position of sleeperstructures’ cracks and evolution. Along with the fatigue loading, the effect of the concretesleepers’ internal stress redistribution phenomenon on local stress concentration andfatigue resistance.