Live Load Distribution Factor for Tank Loading on Slab-Girder Bridges

The aim of this research is to obtain the bending moment and shear live load distribution factors (LLDFs) for interior girders of simply supported slab-girder bridges subjected to continuous loading, such as military tanks. The effective parameters considered in calculating the live load distribution factor were: Girders' number and spacing, span length, slab thickness and the longitudinal to transverse ratio of deck stiffness. Over fifty 3D finite element models were created based on the existing information of bridges in the USA. An equation was obtained for the distribution factor and its validity was assessed against the numerical results. The proposed equation was compared with the AASHTO-LRFD equation for one lane of standard truck loading and also with the equation proposed by the US army corps of engineers for military vehicles. The accuracy of the equation was also verified by performing several sensitivity analyses for the parameters involved. It is concluded that the proposed LLDF equation predicts the distribution factor more accurately than the above mentioned specifications.