A parametric study on fatigue life of plate girder railway bridge with varying velocity of rolling stock

It is important to measure the fatigue life of a structure as it helps in finding the probable life of a structure before its failure. It also helps in making cost effective decision on existing structure regarding replacement or rehabilitation in time. In this study deterministic approach is used for the estimation of fatigue life of a plate girder railway bridge. Finite element analysis is carried out using software to find the critical region of fatigue failure and the stress developed there. Number of cycles of different stress range during the movement of train is evaluated with the help of S-N curve. The S-N curve is selected based on type of welds and type of stress considered. Rain flow counting method is used for evaluating the number of cycles corresponding to each stress range. The fatigue damage is then evaluated by using Palm Miner damage accumulation rule and corresponding fatigue life is evaluated. The fatigue life corresponding to different velocity of train ranging from 30 kmph to 140 kmph is generated similarly and compared to find the influence of velocity of moving load on fatigue life of structure.