PRIMMETRIC STUDIES FOR OPTIMIUTION OP R. C. GIRDER BRIDGES

Abstract

Bridges are very important as for as security and development of I nation. The girder bridges are most common type of super structure in India. In the absence of focussed study on optimal design of girder bridges, this study to consider longitudinal girders and cross—girders as main design variables have been taken up. Two road widths i.e. two lane bridge and four lane bridge with span of 21 meter have been choosen for study. The longitudinal girders are varied from 3 to 5 in case of two lane bridge and 5 to 8 in case of four lane bridge. The cross girders are varied from 5 to 7. A total of 21 case with different loading combinations have been studied. The analysts has been carried out by grid analysis and design have been done by elastic method. Cost have been calculated as equivalent volume of concrete. A combination of longitudinal and cross girders for eacn of the two road width have been arrived at based the minimum volume cost.