Mechanical behavior of steel-concrete composite boxes reinforced with composite materials: Analysis and modeling

Recent advancements in composite bridges have inspired new strategies for flexural reinforcement of metal box girders. This study analyzes the behavior of a simply supported steel box girder reinforced in bending with a prestressed CFRP composite plate, focusing on deflection, interface stresses, and interfacial slip. Two slab-girder connections are considered: studs and adhesive. Using both an analytical model and a 3D finite element model in Abaqus, the effects of prestressing force and CFRP content in hybrid plates are evaluated. Results show that higher prestressing force reduces deflection and stresses, while increasing CFRP content amplifies interface stresses. Interfacial slip is greater in I-beams than in box girders, and configurations with multiple layers of prestressed CFRP offer the best performance by minimizing deflection and stabilizing stress distribution.