Lateral Distribution Factors in Heavy Vehicle Bridge Access Decision-Making

Abstract

Lateral distribution factors (LDFs) indicate the proportion of load effects carried by bridge elements across the width of the bridge deck. Such factors facilitate more informed assessments for heavy vehicle access on existing bridges. Alas, for heavy vehicles travelling on existing Australian bridges, the LDFs are relatively unknown. This study aims to determine such factors for four test vehicles on three concrete bridge families. Each family comprises five simply-supported single spans. Two design lane positions and two load effects, bending moment and shear, are considered. Altogether, 240 finite element (FE) analyses are conducted to obtain the LDFs. It is found that the LDFs vary with bridge deck stiffness, spans, test vehicle, and axle width. Additionally, published AASHTO formulae are found to be suitable for only some Australian vehicles and bridge decks. Ultimately, these distribution factors allow a quick means for analysing the effect of such heavy vehicles without having to perform time-consuming 3D FE analysis when assessing safe vehicle access to bridges.