Distribution Factors For Curved I-Girder Bridges

A study using finite element analysis was made to determine rational factors for the lateral distribution of live loads on typical composite curved I-girder bridges. Within practical ranges, variations in girder stiffness and crossframe spacing had relatively small effects on the factors. The central angle per span and the girder spacing had the largest effects identified. Graphs showing the factors as a function of central angle for two representative girder spacings were developed for use with four-girder bridges. It was also shown that reasonable factors can be obtained from a V-load modification of the factors for straight bridges given by AASHTO. Such factors tend to agree with the finite element results for the exterior girders, but are conservative for the interior girders. Comparisons are also made with the factors given in AASHTO's Curved Girder Guide Specification.