Diagonal tensile failure mechanism of reinforced concrete beams

The mechanism of diagonal tensile failure of RC beams without shear reinforcement, which is difficult to solve by means of experimental and analytical study, is investigated. The close relationship between the fracture modes and the transfer stress at shear cracks is clarified, and the experimental results are verified by the finite element method taking into consideration the influence of a splitting tensile crack and dowel action. In RC members without shear reinforcement, the width of a shear crack increases owing to the occurrence of a splitting tensile crack along the main bars. As a result, the transfer stress of a shear crack cannot be generated and the shear crack grows and propagates rapidly. This paper also puts forth that FE analysis, in which not only shear crack but also splitting tensile crack are modeled discretely, can predict the size effect on diagonal tensile failure strength of RC beams without shear reinforcement.