EXPERIMENTAL STUDY: STRENGTHENING OF REINFORCED CONCRETE MEMBERS USING EXTERNALLY BONDED FRP COMPOSITES

Abstract: The rapid deterioration of reinforced concrete (RC) infrastructure due to corrosion, increased service loads and environmental exposure has created a strong demand for efficient strengthening and retrofitting techniques. Fiber reinforced polymer (FRP) composites have emerged as a promising alternative to conventional steel plate bonding because of their high strength-to-weight ratio, corrosion resistance and ease of installation. This paper presents a concise review of the application of externally bonded FRP systems for the flexural and shear strengthening of RC beams and for the confinement of RC columns.

Key experimental and analytical studies are discussed to highlight improvements in strength, stiffness and ductility, as well as changes in failure modes associated with FRP retrofitting. Particular attention is given to bond and debonding behaviour, the role of structural adhesives, and practical aspects such as constructability and durability.

Existing international guidelines and design provisions for FRP-strengthened RC members are briefly outlined, together with current limitations and gaps. The review shows that externally bonded FRP systems can significantly enhance the performance of deficient RC members, but design is often governed by brittle debonding or FRP rupture, and long-term durability data and unified standards are still evolving.

Keywords: Fiber reinforced polymer (FRP); Reinforced concrete (RC); Retrofitting; Flexural strengthening; Shear strengthening; Column confinement; Structural adhesives.