Analysis of Shear Live Load Girder Distribution Factors in Integral bridges using the Finite Element Method

This paper studies the accuracy of AASHTO Standard Specifications and AASHTO LRFD design specifications girder distribution factors (GDFs) equations and their applicability to integral abutment bridges (IABs). A three-dimensional (3D) finite element (FE) model of the Scotch Road integral abutment bridge was developed using the finite element software ABAQUS/Cae. The bridge was subjected to vehicular live loading in single and multiple lanes in the FE model(s). The FE model was calibrated using load-displacement data obtained from field testing due to static truck loading. A comparison between the GDFs obtained from the FE models to those computed using both design codes was performed to evaluate their accuracy. A limited parametric study was conducted to evaluate crucial design parameters such as bridge deck thickness, span length, and piles lengths. The results showed that AASHTO LRFD GDFs equations are more conservative compared to those of AASHTO LFD equations in all cases. However, GDFs from the FE models compared more favorably to those calculated based on both design codes for the case single lane loading.