ANALYSIS OF EXISTING BRIDGE FOR FATIGUE LIFE

Indian road congress (IRC) recommends a design procedure, prescribed in IRC 21 for design of bridges for flexure. The procedure takes a “Hypothetical vehicles” to be considered across the bridge for analysis. However in real situation, the vehicles which move on the bridge are quite different from the hypothetical vehicle considered in IRC. Hence, this procedure does not reflect the realistic scenario. It is felt that the effect of movement of real vehicles has to be examined. The bridge when designed only for flexure may be subjected to premature failure as the concept of fatigue is not accounted which is an important parameter to be analysed for estimating life of structure. Considering “Real vehicles” for analysis purpose makes more sense. “Moving load analysis” conducted to determine the design bending moment will yield more realistic and reliable data. Hence fatigue analysis is carried out by considering real vehicles obtained from traffic survey and its implicit factor was found. Therefore in this work one of the existing bridges have been evaluated for fatigue life using finite element package as per Indian standard codes