A Comprehensive Review of the Flexural Behavior of RC Beams strengthened by Externally Bonded and Near-Surface Mounted Techniques using FRP and Metal Materials

Abstract

Near surface mounted (NSM) uses of fiber reinforced polymer (FRP) in civil construction have become more common globally and can provide reliable strengthening and repair systems for concrete structures that are already in place. It has been extensively studied how concrete structural members that have been strengthened using FRP and the externally-bonded (EB) technique respond to fatigue and monotonic loads. However, little is known about how NSM FRP-rehabilitated concrete structures respond to monotony and fatigue. This research aims to review the literature on the behavior of R.C beams strengthened with both NSM and EB procedures because there aren't many prior review studies both EB and NSM methods or focus on NSM components. It compares the advantages and disadvantages of each strategy, makes recommendations for the future. The review also highlights the critical of different strengthening materials (both FRP, metallic materials), the techniques employed, the properties of the strengthening elements (like area, shape), other elements affecting the behavior of the RC beams for each technique. The results show that the load-carrying capability of the RC beams strengthened by both techniques had highly influenced by the strengthening elements' mode of failure. Furthermore, the NSM technique may significantly enhance the bonding behavior between FRP composites and the concrete. Additionally, at the FRP-adhesive interface over the grooves, 28.0% and 14.0% of all NSM bonds, respectively, suffered FRP rupture mode and a combination of FRP rupture and debonding.