Local strengthening and repair of concrete bridge girders using shape memory alloy precast prestressing plate

Whether due to accidents, natural hazards, or harsh environmental conditions, concrete structures and bridges, in particular, experience local damages throughout their service life. Based on their severity, these damages can compromise the integrity of the structure. External prestressing is often used as an effective strengthening or repair technique for vulnerable or damaged structures, respectively. However, applying external prestressing in local regions of the structure with limited space can be problematic and not feasible for conventional prestressing techniques. This study investigates an innovative method for applying external prestressing in local regions of bridge girders using externally mounted precast prestressing plate reinforced with shape memory alloy wires. A thin mortar plate with embedded curved shape memory alloy wire was experimentally tested to validate the proposed prestressing concept. Afterward, finite element analysis was performed on a concrete bridge girder to numerically investigate the performance of shape memory alloy precast prestressing plate in enhancing the shear and flexural behavior of the girder. Experimental and numerical results evidently demonstrated the feasibility and effectiveness of the innovative method in strengthening and repairing concrete structures through external local prestressing.