Flexural strengthening of preloaded reinforced concrete continuous beams: An experimental investigation

Abstract

This paper investigates experimentally the preloading effect on the flexural behavior of reinforced concrete strengthened continuous beams. Five continuous reinforced concrete beams were tested; they all had the same dimensions and the same reinforcement detailing. Two types of strengthening were used; strengthening with RC jackets and strengthening with CFRP sheets. The five specimens were tested before and after applying the strengthening techniques, but under different preloading levels. For all specimens, deflections and reinforcement strains were recorded throughout the test duration before and after strengthening.The results demonstrated that in case of strengthening with RC jackets, preloading level had an essential role in increasing the flexural load-carrying capacity and the deformability of RC continuous beams, while in case of strengthening with CFRP sheets it didn’t influence either the flexural load-carrying capacity or the deformability of beams. Also comparing the two methods of strengthening showed that strengthening with CFRP sheets improved strength, ductility and dissipated energy and decreased the mid-span deflection at ultimate load of RC continuous beams. On the other side, strengthening with RC layers improved strength, dissipated energy, deflection at ultimate load and ductility of RC continuous beams.