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Shear Performance of Steel Fiber in Prestressed Concrete Railway Sleepers

The addition of steel fibers to concrete helps improving post -cracking tensile strength and hence leads to a significant increase in shear strength of reinforced concrete beams. Using steel fiber in structural elements such as pre-cast concrete beams or prestressed beams in road and railway bridges ductility, increase the energy absorption, gives better performance in fatigue, increase shear capacity and incorporates less stirrups spacing. 1n this paper, the shear performance of steel fiber in monoblock priestessʹs concrete sleepers is investigated. From the analyses result, equations for determination of shear capacity of steel fiber used in concrete are determined. Monoblock priestessʹs concrete sleepers arc in fact p riestessʹs concrete beams with critical loading compared to conventional concrete beams (bridge beams in road and railway), where the beams have no stirrups even in area where the prestressing is applied. According to the results when steel fibers are adde d to the Prestressed concrete beams, of shear capacity, a decrease in stirrups amount, a better crack control, and some increase in stiffness and an increase ultimate strength of such beams can be gained. Bence, it can be said that in Prestressed concrete sleepers instead of increasing the prestressing parameter (which reduces the ultimate stiffness of the sleepers), addition of fibers is useful increase the beam stiffness after cracking and to increase the ultimate shear capacity of the beams. The results of experimental study also showed that the presented formulae for calculation of shear capacity of steel fiber in concrete have been are overestimated.