Abstract
The shear strength of reinforced concrete members with or without shear reinforcement is influenced by the shear span to effective depth and longitudinal tensile reinforcement ratios. In high-strength concrete, if the paste has a higher strength than the aggregates, then propagation of cracks is possible through the aggregates rather than around the aggregates, and the concrete may fail with a brittle failure, which is against most of the guideline’s philosophies. This paper investigates experimentally the influence of the shear-span to effective depth ratio and the longitudinal tensile reinforcement ratios on the behavior of the shear strength of HSC beams having no shear reinforcement. A total of fifteen reinforced high-strength concrete beams with different longitudinal reinforcement ratios were fabricated and then tested under a two-point bending test with shear-span to effective depth ratios varying from 1 to 3. Experimental results were compared based on design codes and state-of-the-art models. The influence of shear-span to effective depth ratio and longitudinal tensile reinforcement ratio is unaccounted for in most design guidelines and prediction models; therefore, the predicted values are either underestimated (up to 50%) or overestimated, except for the Zsutty Model, which has accurately predicted the shear strength values for all shear-span to effective depth and longitudinal tensile reinforcement ratios. As in the future, high-strength concrete will be more likely used in RC construction, this study directs the understanding of model assumptions for shear prediction before its use.