Truck Platoon Impacts on Prestressed Concrete Girder Bridges

Abstract

‘Connected and Autonomous Vehicle’ technology allows for the formation of truck platoons which consists of closely spaced trucks travelling at high speeds. Although platooning offers many benefits, its impact on bridges and current design codes require attention. Specifically, because platoons may be heavier than what bridges were designed to withstand and because the Canadian Highway Bridge Design Code (CHBDC) in CSA S6:19, which offers empirical equations to estimate the live load distribution factor (Ft), may not be adequate for autonomous vehicles, especially regarding lane width requirements. The goal of this study is twofold: first, assess the performance of prestressed concrete girder bridges under truck platoons, considering corrosion and climate change effects, and second, evaluate the performance of CHBDC equations in estimating Ft for bridges with reduced lane widths that do not meet standard requirements and provide an amplification factor for improved accuracy. This study begins by comparing the reliability of bridge archetypes under routine traffic versus truck platoon loads. We then incorporate structural deterioration models to account for the effects of corrosion and climate change. Finite element models are employed to evaluate CHBDC Ft estimates, and genetic programming is utilized to develop the amplification factor. The results indicate that closely spaced platoons, corrosion and climate change all decrease the bridge reliability and that even if platooning satisfies the safety criteria at the ultimate limit state, it may falter at the serviceability limit state. CHBDC performs well for interior moment Ft estimates, but has unconservative cases for exterior moment and shear, especially for bridges with reduced lane widths. The load type showed negligible effect on Ft, while reduced lane widths consistently increased Ft. The proposed amplification factor was validated and resulted in more accurate Ft estimations.