Evaluation of Dynamic Load on Railtrack Sleepers Based on Vehicle-track Modeling and Analysis

The present study reports the results of a rigorous dynamic interaction analysis that accounts for the vehicle-track characteristics and rail imperfections. In order to perform a rigorous dynamic analysis, a model involving all components of the track structure and vehicle parameters are required. A vehicle model (conforming to Indian Railways) with 17 degrees of freedom has been considered. The track model consists of rail, rail-pad, sleeper, ballast, sub-ballast, subsoil and a track length encompassing 12 prestressed concrete sleepers. The dynamic interactive analysis is carried out between the vehicle and track in the time domain using a finite element software. The results of the interactive analysis give responses in the form of reaction time histories at the rail-seat locations during the passage of vehicle. A parametric study is carried out to assess the influence of different track parameters on the dynamic load on the railtrack sleepers. Based on this study, suitable load amplification factors are arrived at to facilitate an improved design basis for an equivalent static analysis in practical designs of sleepers.