Impact of Stiffener Configuration on the Structural Performance of Orthotropic Steel Bridge Deck

The impact of longitudinal stiffener configurations on the structural performance of orthotropic steel bridge decks (OSD) was systematically investigated, with emphasis on U-shaped, T-shaped, and rectangular ribs. Finite element analysis was employed to evaluate deformation and stress distribution under three critical loading scenarios: vertical uniform load, vertical eccentric load, and lateral uniform load. Equivalent models ensuring identical steel usage, moment of inertia, and centroid alignment were established to compare five stiffener configurations. Results demonstrate that U-rib configurations exhibit superior performance in controlling local displacements and minimizing stress concentrations. Under eccentric loading, U-ribs significantly reduce deck displacement and mitigate stress fluctuations at critical junctions compared to alternative stiffeners. Stability analysis further reveals that U-ribs achieve stability coefficients substantially higher than open-section alternatives, particularly excelling under lateral loading due to enhanced torsional rigidity. Parametric optimization identifies key geometric thresholds where U-rib thickness exceeding 6 mm yields diminishing returns in stress reduction and stability enhancement, while deck flange thickness beyond 16 mm provides marginal improvements in displacement control despite increased material usage. An optimized design combining 6-mm U-ribs with 16-mm deck flanges is proposed, balancing structural efficiency with stringent deformation requirements for high-speed rail bridges. These findings provide foundational insights for optimizing stiffener selection and enhancing the longevity of orthotropic steel bridge decks in heavy-load applications.