Near Surface Mounted Strengthening using Fiber Reinforced Polymer (FRP)

This paper reviews recent advancements in strengthening reinforced concrete (RC) and unreinforced masonry (URM) structures using Fiber-reinforced polymers (FRP) through the near-surface mounted (NSM) technique.Interest in NSM-FRP has grown steadily due to its high strength, stiffness, resistance to corrosion, and ease of installation.Both experimental and numerical studies consistently demonstrate its effectiveness in flexural and shear strengthening.In addition, the use of prestressing and anchorage systems has been shown to further improve performance by increasing strain utilization and influencing failure modes.The effectiveness of NSM systems largely depends on the bond between the FRP and the surrounding material.Key factors influencing this bond include groove spacing, adhesive type, temperature conditions, and anchorage details.Research shows that inadequate groove spacing can compromise bond performance, which has led to the development of reduction factors and predictive models to address this issue.Compared to the more conventional externally bonded reinforcement (EBR) method, NSM generally offers stronger bonding, better durability, and more efficient load transfer.Although challenges remain, particularly regarding bond reliability and proper installation, NSM-FRP stands out as a highly promising strengthening solution.It provides distinct advantages over EBR and presents significant opportunities for further research and wider practical applications in structural engineering.