Optimization of Double Track Railway Bridge Superstructure Using FEM

The purpose of this paper is to optimize truss bridges with a span of 50 m and 60 m long at different heights while they are subjected to wind and railway loading. Later the bridges are compared according to the most important analysis outcome such as deflection in order to identify the optimum bridge height. The analysis and design of double track bridge for modified broad gauge loading is done and further the optimization process is carried out. Principal of static analysis is applied keeping limit state design as its constraint. The optimization is carried by varying heights so that the top chords are located on approximately curved parabolic shape and designing the members using Jindal flat flange sections. Use of Jindal flat flange sections add newness to the structure. In the present paper an effort has been made to use the method of actual wheel load application and to optimize the through truss bridges with different span. Analysis and design of these bridges is done using STAAD PRO-V8i (SS5) (finite element analysis) software. In general the output of the work shows that the weight minimization can be done by designing the bridge somewhat deeper than they are normally built and the performance of bridge regarding the use of Jindal sections. Keywords—Actual wheel load, double track railway bridge, finite element analysis (FEM), Jindal flat flanges, limit state design.