Effect of variables on shear strength of concrete beams

Although considerable research has been conducted on the shear strength of reinforced concrete members without web reinforcement, the debate as to the effects of the major variables on the ultimate shear strength (v(u)) and c racking shear strengths (v(c)) has yet to be unequivocally established. Pre vious research on the subject has at times been unclear or often yielded co ntradictory results. The intent of this paper is to shed some light and cla rify some of the misconceptions regarding the effects of the compressive st rength (f'c), tensile reinforcement ratio (rho), and shear span-to-depth ra tio (a/d) on v(u), and v(c) of steel-reinforced concrete beams without web reinforcement. The analysis uses extensive shear strength data retrieved fr om existing literature for both normal strength and high strength concrete members. Results show that a/d significantly affects v(u), whereas its effe ct on v(c) is much less significant. The effect of f'c on v(c) is not negli gible and should be accounted for in strength analysis. The impact of rho o n v(c) is insignificant in the case of short beams (a/d < 2.5).