Investigation of Approach Slab On Behaviour of Ballasted Track and Optimization of geomtric parameters in Transition Zone for Railway Short Span Bridge

A suddenly change and non-uniform track vertical stiffness along the railway track among bridges transition zone increased dynamic loads, deformations asymmetric ,bumpy rails, damage track components and train and so maintenance costs are increasing. One of the methods used to solve these problems is creating approach slab around the structures and bridges. So this paper Optimization Dimension of Concrete Approach Slab in Transition Zone for Railway Short Span Bridge studied according to the vertical displacement rails, vertical displacement ballast layer and normal stress distribution in the middle layer of ballast. For this purpose finite element model of the ballasted track and bridge is created and verified. results show that in transition zone for railway short span bridges length of 6 m, a thickness of 50 cm and a slope of 5% are as optimal geometric parameters for the approach slab. So vertical displacement track and vertical displacement ballast layer with optimal approach slab respectively to 24% and 18% are decreased and the contrary normal stress distribution in the middle layer of ballast 40% is non-uniformed but normal stress is under level allowance stress for ballast layer