Shear Behavior in Beams Reinforced with Glass-Fiber Reinforced Polymer Bars (GFRPB) without stirrups

Abstract

The behavior and shear strength of concrete beams reinforced with glass fiber-reinforced polymer (GFRP) bars was investigated. Total of six reinforced concrete beams without stirrups were constructed and tested up to failure. The beams measured 1400 mm long, 150 mm wide and 300 mm deep and were tested in two-points bending with constant shear span 350 mm in all tested beams, and shear span to depth ratio a/d 1.37. The test variable was the reinforcement ratio. The test beams included three beams designed as tension control (T.C) with GFRP bars, three beams designed as compression control (C.C) with GFRP bars. The test results were compared with predictions provided by ACI 440.1R-15 design guideline and proposed equations in the literature. The test results indicated that the relatively low modulus of elasticity of FRP bars resulted in reducing shear strength. In addition, shear strength provided by ACI 440.1R-15 guideline underestimate shear strength capacity in which proposed equations in the literature had given better prediction than ACI 440.1R-15. The failure mode in T.C beams is diagonal tension by bond failure not by rupture of FRP and C.C beams is shear compression by crushing of the web in extreme fiber.