Ten simply supported reinforced concrete T-beams were experimentally tested under two symmetrically concentrated loads. Nine of the studied beams were made of High Strength Concrete (HSC) with mean compressive strength 70 N/mm² while the control beam was made of normal strength concrete (NSC) with compressive strength 30 N/mm². Five of the studied beams were reinforced by High Tensile Steel (HTS) bars and the other four specimens were reinforced by Glass Fiber Reinforced Plastics (GFRP) bars. The control beam was reinforced by HTS bars as main reinforcement. The web reinforcement for all the test beams was in the form of vertical stirrups. All beams were designed according to the provisions of ACI 318-99. The studied parameters were the amount of web reinforcement, shear span to depth ratio (a/d) and type of main reinforcement (GFRP and HTS). The actual shear strength of each beam was compared with the strength predicted by different codes of practice such as ACI 318-99, BS-8110, and ECCS 203-2001in order 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 found that increasing a/d from 1.5 to 3.5 resulted in reducing the ultimate capacity of the studied beams of approximately 42%. In addition, increasing the amount of web reinforcement μv from 0.202 to 0.324 resulted in increasing the ultimate capacity of the studied beams by approximately 53%. Moreover changing the type of main reinforcement from HTS to GFRP, while keeping the reinforcement ratio constant at μ=0.58 μb, resulted in a great reduction of the ultimate capacity of the studied beams.
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