Shear Failure Mechanism in Concrete Beams

The aim of the paper is to investigate the shear failure mechanism and shear capacity in longitudinally reinforced concrete beams without transverse reinforcement. It has been found that the shear span-to-depth ratio and a beam size are important parameters which significantly affect the failure mode in the investigated members. The “size effect”, which is described in professional literature as a decrease of shear strength with the increase of the members depth, is not evaluated sufficiently enough. The effective length-to-depth ratio which has been identified in this paper, also has a considerable influence on the contributions of the shear resistance mechanism and thus the ultimate shear capacity. In the paper it has been shown that members characterized by the same shear span-to depth ratio but different effective length-to-depth ratio can fail in a different way.