Maximum Shear Capacity of Reinforced Concrete Members

This paper investigates the maximum shear strength limits specified in the ACI Code and the combinations of shear span, concrete strength, and amount of shear reinforcement where this limit is very conservative. A series of new experiments are described and their results, along with those of 127 experiments from the literature, are compared to predictions from the ACI, AASHTO-LRFD, and CSA codes. It is shown that an upper shear stress limit of 0.225f(c)' provides a good estimate of maximum shear capacity. The current ACI limit, on the other hand, seriously underestimates the shear strength of high-strength concrete members when they include large quantities of shear reinforcement or have short shear spans.