Comparative study of AASHTO load and resistance factor design distribution factors for slab-girder bridges

The distribution factors for slab-on-girder bridges in AASHTO load and resistance factor design (LRFD), and the work upon which they are based, were compared with results from an independent analysis based on the finite strip method. The primary objective of the current work offers an independent comparison of 352 of the same bridges used in the development of the AASHTO LRFD factors. The comparisons were limited to interior girders of slab-on-girder bridges, and the results were compared closely within reasonable deviation. Because of the importance of the AASHTO factors, this independent confirmation is documented. Moreover, statistics on the variability are helpful for calibration where analysis factors are involved.