LIVE LOAD DISTRIBUTION IN INTEGRAL COMPOSITE STEEL BRIDGES

In recent years, there has been an increased interest in integral brid ges for highway applications due to their inherent economy, serviceabi lity, and strength. This study deals with the live load distribution o f integral composite steel bridges near the abutments. Girder distribu tion factors for sheer and bending moment in interior as well as in ex terior beams are determined. A comparison between the response of inte gral bridges and their jointed counterpart is also included. Single an d continuous spans are considered in the investigation. The applied lo ading is composed of several side-by-side HS20 trucks. Linearly elasti c finite element analysis is used to analyze the three-dimensional bri dge systems. The results of the study indicated that shear in the inte rior beams and the corresponding girder distribution factor are lower in integral bridges than in simply supported bridges. As the pile leng th to fixity increases, the shear and moment in the beams near the int egral abutment decrease. Further, as the length of the wingwalls in in tegral bridges increases, the shear and moment in the interior beams i ncrease.