Concrete contribution to the shear resistance of FRP-reinforced concrete beams
Ahmed, Ahmed Kamal El-Sayed
Corrosion of steel reinforcement in concrete structures causes deterioration of concrete, resulting in costly maintenance and repair. Many steel-reinforced concrete structures exposed to deicing salts and marine environments require extensive and expensive maintenance. Recently, the use of fibre-reinforced polymers (FRP) as an alternative reinforcing material in reinforced concrete structures has emerged as an innovative solution to the corrosion problem. However, due to the difference in mechanical properties between steel and FRP reinforcements, the shear strength of concrete members reinforced with FRP longitudinal reinforcement may differ from that of members reinforced with steel. An experimental program including two phases is described. The experimental program was conducted at the University of Sherbrooke to investigate the effect of using FRP bars as longitudinal reinforcement on the shear strength and behaviour of concrete beams without web reinforcement. The first phase included 15 large-scale concrete slender beams reinforced with glass FRP, carbon FRP, or conventional steel bars. Nine beams were constructed using normal-strength concrete, whereas six beams were constructed using high-strength concrete. The test variables were the reinforcement ratio and the modulus of elasticity of the reinforcing bars as well as the concrete compressive strength. The second experimental phase included 12 large-scale concrete deep beams reinforced with glass FRP, carbon FRP, or conventional steel bars. The test beams of this phase were constructed using normal-strength concrete and the test parameters were the reinforcement ratio and the modulus of elasticity of the reinforcing bars as well as the shear span-to-depth ratio. The influence of the considered variables on the shear strength and behaviour of the tested beams in the two phases is presented. An analytical investigation to examine the validity of the available design provisions of concrete contribution to shear strength for members longitudinally reinforced with FRP bars is reported. For this purpose, the shear strengths of the tested beams are analyzed using the shear design provisions of the different available codes, manuals, and design guidelines. The results of the analysis are compared with the experimental values. Based on the findings of this investigation, a proposed shear design equation is presented. The proposed equation is verified against experimental shear strengths of 107 specimens tested to date, including the specimens in this investigation. In addition, the proposed equation is compared to the major design provisions using the available test data to further evaluate its reliability.
- Génie – Thèses