Novel Repair Technique for Bridge Decks Using a System of Coupled Prestressing Plates and Shape Memory Alloys

Transverse cracking is a critical deterioration mechanism in concrete bridge decks. These cracks facilitate the ingress of detrimental agents, which reduce the durability of the deck-girder system by promoting corrosion of the reinforcement. To address this issue, this investigation builds on the effectiveness of shape memory alloys (SMAs) in structural rehabilitation and evaluates their use in an external repair technique denominated coupled prestressing plate (CPP) system. The proposed methodology, studied experimentally and numerically, involves enclosing damaged regions with adaptive prestressing system (APS) assemblies anchored at their ends by precast concrete plates. In the experimental phase, a CPP system with NiTiNb-based APS assemblies is installed over a region of a bridge deck specimen containing fatigue-induced transverse cracks. After transferring prestressing forces through the shape memory effect (SME) activation, approximately 12% of residual deflection is recovered, with crack closures of up to 53% under unloaded conditions. The CPP-equipped specimen is retested under cyclic loading, and the reinforcement exhibits strain reductions of up to 20.5% compared to the unrepaired condition. In the numerical phase, the crack growth recorded experimentally is simulated using the cohesive zone method, defining cohesive interactions along planes following the transverse cracks. The results indicate that the model captures the residual crack openings, average healing, and residual deflection satisfactorily before and after the SME activation. A parametric analysis of different APS configurations in CPP systems shows that APS designations can achieve crack closures of up to 84%. Overall, the investigation demonstrates the potential of the SMA-based CPP technique for mitigating transverse cracks in bridge decks and provides a basis for numerical model parameters and technology optimization.