Ageing transportation infrastructure requires innovative solutions to enhance safety, resilience, and sustainability. This study addresses this challenge by advancing Fiber Reinforced Polymer (FRP) strengthening systems bonded to concrete substrates and integrating Distributed Fiber Optic Sensors (DFOS) for real-time structural monitoring. A self-sensing FRP system was employed to map strain and stress distributions along the FRP-concrete interface. Six reinforced concrete beams, five of which were strengthened with adhesively bonded FRP plates, were tested under four-point bending. Embedded fiber optics enabled high-resolution strain monitoring, allowing precise identification of failure mechanisms, including adhesive debonding and cohesive delamination. The results demonstrated the interface engagement of the adhesive, as well as the mechanisms occurring, such as debonding and cohesive failures. Strain distribution analysis revealed cracking patterns, enhancing early damage detection capabilities. The proposed provides a robust and practical framework for self-monitoring retrofitting measures, reducing inspection requirements while improving long-term structural performance. This approach contributes to the development of sustainable and intelligent retrofitting solutions for infrastructure systems.