Applicability and validation of improved live load distribution factors for commercially available shallow steel tub girders

Press-Brake-Formed Tub Girders (PBFTGs) provide an innovative and efficient solution for short-span steel bridges. Recognized as a 2021 Focus Technology by the American Association of State Highway and Transportation Officials (AASHTO) Innovation Initiative, these galvanized, shallow trapezoidal boxes are fabricated from cold-bent structural steel plates. This study aims to quantify the potential impact of improved live load distribution factors (LLDFs) on the applicability of PBFTGs. Using three-dimensional finite element analysis, the live load distribution behavior of a matrix of 720 Valmont U-BEAM™ bridges, a commercially available PBFTG solution, was analyzed with varying parameters. Statistical analysis was employed to assess the effectiveness, prediction power, and accuracy of the improved LLDFs. The impact of the improved LLDF predictions was then examined by performing a design feasibility and applicability assessment. The findings of this study contribute to the optimization of PBFTG design and the expansion of their use in short-span steel bridge construction.