Analyzing Nonlinear Response in Reinforced Concrete Slab-on- Girder Bridges for interior girder: Influence of Intermediate Diaphragm

Abstract This study presents the outcomes of a thorough nonlinear finite element analysis conducted on slab-on-girder reinforced concrete bridges. The analysis encompasses nonlinear aspects like concrete cracking, compression behavior, and reinforcement yielding. Thirty-six bridges were examined under truck loads specified by the Egyptian Code (ECP 201–2017) 11, alongside the bridges' self-weight. Among these, nine bridges had varying spans and widths, necessitating adjustments in the number of longitudinal girders to maintain uniform girder spacing. Initially, each bridge underwent analysis without intermediate diaphragms, followed by a reanalysis with the insertion of intermediate diaphragms at the mid-span and support locations. Additionally, nine bridges without intermediate diaphragms underwent linear analysis before nonlinear analysis. Furthermore, nine bridges with varied spans and girder spacings but constant width were analyzed. The finite element model was validated using field test data from the literature. Through a parametric investigation, it was observed that the presence of intermediate diaphragms, firmly linked to the longitudinal girders, notably improves transverse load distribution, resulting in reduced loads on the longitudinal girders. This improvement escalates with increasing bridge width. Finally find the proposed equation of moment distribution factor of interior girder. This equation gives a good agreement with analysis.