Strengthening Reinforced Concrete Beams by Using Different Types and Methods of Fiber-Reinforced Polymers: A Critical Review

Fiber-reinforced polymer (FRP) composites are widely used in concrete technology due to their high mechanical and durability properties. FRP has become a mainstream material not only to strengthen damaged elements but also to sustain more service loads and solve long-term ever-growing issues of new infrastructures. Therefore, this review aims to establish a database of research works that focus on the assessment of flexural, shear, and torsional strengthening of reinforced concrete (RC) beams using various types and application methods of FRP composites. The efficiencies of these strengthening techniques were compared in terms of structural behaviors of RC beams, types of FRPs, wrapping configurations, etc. This state-of-the-art review reveals that FRP composites can be used successfully to recover the strength of damaged beams or to improve the structural behaviors of new elements. Furthermore, a statistical analysis was conducted to determine the increment factors for various parameters affecting the structural behaviors of RC beams. It was found that FRP composites were more beneficial for torsional strengthening compared to flexural and shear retrofitting in terms of load capacity and ductility. In addition, the change of FRP layers was more significant than varying FRP wrapping methods, sizes, and types. Finally, based on the compiled database and statistical data, the article proposes some methods for using FRP composites to strengthen RC beams under various load conditions. (C) 2022 American Society of Civil Engineers.