Ten simply supported reinforced concrete beams, with web reinforcement in the form of vertical stirrups, were tested under two symmetrically concentrated loads to investigate the shear strength of High-Strength Concrete (HSC) T-beams reinforced by Glass Fiber Reinforced Plastics (GFRP) and High Tensile Steel (HTS). Nine of the studied beams were made of HSC with mean compressive strength 70 N/mm², five of them were reinforced by HTS bars and the other four specimens were reinforced by GFRP bars as main reinforcement. The control beam was made of normal strength concrete (NSC) with compressive strength 30 N/mm² and reinforced by HTS bars as main reinforcement. All beams were designed according to the provisions of (ACI 318-99). The studied parameters were the amount of web reinforcement ( ), the shear span to depth ratio (a/d), and the type of main reinforcement (GFRP or HTS). The actual shear strength of each beam was compared with the predicted strength by different codes of practice for NSC beams reinforced by FRP bars such as (JSCE-97), (CHBDC-Draft-98), and (ACI-440-2001) codes in order to assess the validity of such codes when applied to HSC beams reinforced by GFRP with web reinforcement and to establish an empirical formula for the analysis and design of HSC beams reinforced with GFRP bars. Within the limits of the test results of this research it was concluded that, for beams reinforced by GFRP, the flexural reinforcement ratio ( ) must be increased to about (1.4 ), as recommended by (ACI 400-2001), to make the design equations of (JSCE-97), (CHBDC, Draft-98), and (ACI 400-2001) applicable for predicting the shear strength of HSC members reinforced by FRP bars, and there was no NA existed after passing the cracking load . Lower stiffness and low modulus of elasticity in GFRP bars relative to HTS resulted in higher crack width; the crack width in beams reinforced by GFRP was six to nine times that of Beams |
