Effect of fiber parameters and concrete strength on shear behavior of strengthened RC beams

• Fibers are used to enhance shear properties of reinforced concrete beams.
• Egyptian (ECP) and American (ACI) codes.
• Parameters: fiber orientation, fiber thickness, concrete strength, analytical model.
• Fiber parameters and concrete strength affects shear strength.
• Both analytical models have similar trend of shear strength values.

This paper presents the performance of reinforced concrete (RC) beams strengthened in shear. Both experimental investigation and analytical models were presented. Experimental investigation was carried out on nine RC beams of three different sets, as-built beams (unstrengthened), beams strengthened with vertical carbon fiber-reinforced polymer (CFRP) wraps, and beams strengthened with inclined CFRP wraps. The main parameters investigated were concrete strength, CFRP thickness and wraps orientations (90°, 45°). The results of the experimental work indicated that externally bonded CFRP wraps enhanced the shear strength of beams significantly and that inclined CFRP configuration is more effective than vertical ones. Also, it was shown that concrete strength affects the contribution of CFRP regarding shear resistance. Experimental results were compared to analytical models, ACI 440.2R-08 and ECP 208-05. The results showed that the design approaches of both codes are almost similar.