Strengthening Reinforced Concrete Deep Beams with Web Openings Using CFRP, Steel Plates, and Skin Reinforcement

Abstract

Web openings in deep RC beams significantly reduce the strength and stiffness of these structural elements. To overcome this, strengthening practices have been implemented by incorporating various techniques. Several studies have reported on the application of externally bonded fiber-reinforced polymer (FRP) techniques. In contrast, research on use of steel materials, such as steel plates or bars, for strengthening is limited. Therefore, this study applied a carbon fiber–reinforced polymer (CFRP), steel plates, and steel reinforcement to investigate the importance of steel in this area of strengthening. The effects of the opening configuration, installation of the strengthening material, and thicknesses of the CFRP and steel plates were investigated. The application of CFRP, steel plates, and steel reinforcement enhanced the load-carrying capacity of the RC deep beams. Strengthening via steel reinforcement resulted in the maximum improvement among all the installation techniques, except when the CFRP and steel plate thicknesses were increased. Furthermore, maximum improvement was observed when the strengthening material was applied around the outer surface of the opening, compared with the other installation techniques.