DISTRIBUTION OF CONCENTRATED LOADS ON MULTIBEAM BRIDGES

Abstract

The work presented in this Thesis is a continuation of the work carried out by Arya in his Ph.D. thesis for analysing multi-beam bridges. Influence ordinates for moments in various beams were obtained by him for different positions of a unit load on the bridge. Such influence surfaces were obtained by him for a very large number of bridges with a very wide range of para-meter combinations. The influence surfaces for all such bridges are used here to determine the values of maximum moments., in various beams produced by the various standard loadings specified by the Indian Roads Congress. Thus these reaults can directly. be made use of in normal design Practice. Por the experimental verification of the theory for the analysis of multi-beam bridges, a steel channel model has been tested under ideal conditions as assumed in the theory. Pur-ther a 1/4.5 model of 30 feet span four element reinforced concrete channel bridge, to verify the theoretical distribution of wheel loads both under uncfacked and cracked conditions of the bridge at the working loads and the ultimate loads has been tested. Prom the test results of steel as well as concrete model, it is seen that the theory is quite valid for the analysis of multi-beam bridges. For the concrete model, it is seen further, that the experimental distribution of wheel loads is .1 iv nearly the same as theoretical one both under uncracked and cracked conditions, and that the distribution of wheel loads at ultimate load is not much different from that at working load. Therefore, the distribution of wheel load to various beams at working loads can confidently be used for design purposes. -.4 04-