Shear crack concentration in reinforced concrete beams subjected to shear and flexure

The dual potential capacity model was developed in the authors’ previous studies to estimate the shear strengths of reinforced concrete members, in which the shear crack concentration factor was adopted as the key concept of the proposed approach. In this study, a shear test program was carefully prepared and conducted on five reinforced concrete beam specimens to investigate the crack development, propagation, and merging behavior of critical shear cracks. To this end, concrete cover thickness, diameter of reinforcement, presence of skin reinforcement, and shear reinforcement ratio were taken as the main test variables. From the experiments, the crack merging and concentration phenomena were clearly observed, and the crack concentration factors were estimated from the measured flexural and shear crack widths and spacings. The crack concentration factors were compared to those estimated by the dual potential capacity model, and the shear strengths of the test specimens were also compared with those estimated by the dual potential capacity model and other models in detail.