Minimum shear reinforcement in normal, medium, and high-strength concrete beams

This paper presents the evaluation of minimum shear reinforcement requirements in normal, medium, and hitch-strength reinforced concrete beams. Twelve shear tests were conducted on full-scale beam specimens having concrete compressive strengths of 36, 67, and 87 MPa. Different amounts of minimum shear reinforcement were investigated, including the traditional amounts required by older codes and the amounts required by the 1989 ACI Code (revised 1992) and the 1994 CSA Standard. The performance of the different amounts of shear reinforcement are discussed in terms of shear capacity, ductility, and crack control at service load levels. An assessment of the 1989 ACI and 1994 CSA provisions for minimum shear reinforcement is also presented.