Shear Strength of Reinforced High-Strength Concrete Beams with Shear Span-to-Depth Ratios between 1.5 and 2.5

Abstract

Thirty high-strength concrete beams were tested under concentrated loads at midspan to determine their diagonal cracking strength and nominal shear strength. The test variables were the compressive strength of concrete, the shear span-to-depth ratio, and the vertical shear reinforcement ratio. The effects of each test variable were studied separately. Test results were compared with strengths predicted using American Concrete Institute (ACI) 318-95. It was found that for beams with shear span-to-depth ratios between 1.5 and 2.5, ACI Eq. (11-30) generally underestimates the shear strength contributed by the vertical shear reinforcement. New equations are presented for a more accurate prediction of the diagonal cracking strength and the nominal shear strength of reinforced concrete deep beams.