In railway steel bridges, dead load is due to the self weight of the structural member which remains constant over entire service life of the structure. Live load is mainly due to the repetitive train axle loads, for which the fatigue resistance of structural member may be more critical than structural stiffness or strength. The fatigue damage mainly depends on the amplitude of the stress range and the number of cycles made by each stress range in a fixed time period, say a year. The train load in the form of stress spectrum forms one of the important inputs for the analysis of fatigue reliability. The present work deals with the study undertaken to arrive at load spectrums for plate girder bridges of Indian Railways between Mysore and Maddur stations along Mysore-Bangalore sector. The damage analysis is performed on two simply supported bridges with spans of 12.2 m and 18.3 m. The effect of wind loads and other environment load effects, i.e., earthquake, snow, etc., on bridges is not taken into account in the study.
展开▼
