Shear Strength of Reinforced Concrete Deep Beams

This study reports the test results of 16 reinforced concrete deep beams. Eight were tested with loads applied through and supported by columns, and the others by bearing plates. The main variables studied were the force-transferring mechanisms, the compressive strength of the concrete, and the horizontal and vertical stirrups. With identical shear span-to-effective-depth ratios, the shear strength of deep beams increases significantly with the increase in the compressive strength of concrete. The shear strength of deep beams also increases with the increase of the ratio of horizontal stirrups or vertical stirrups. The critical sections for flexure of deep beams were at the centroid of the half load-bearing plate and the faces of the load column, respectively. An analytical method for predicting the shear strength of deep beams with respect to the force-transferring mechanisms is proposed in this study. The shear strength predicted by the proposed method and the strut-and-tie model of ACI 318-08 are compared with available test results. The comparison shows the proposed method can more accurately predict the shear strength of reinforced concrete deep beams than the strut-and-tie model of ACI 318-08.