Investigation of Shear Reinforcement Schemes for RC Deep Beams

Abstract

The aim of this paper is to experimentally investigate the effect of using alternative shear reinforcement schemes on the shear performance of deep beams. Seven deep beams were cast with different shear reinforcement configurations. Three deep beam samples were used as reference and were cast with (1) plain concrete without stirrups, (2) plain concrete with stirrups and (3) steel fiber reinforced concrete without stirrups. The remaining beams were made using two alternative shear reinforcement schemes including inverted U-shape steel angles of 50 mm × 50 mm × 4 mm and inverted U-shape steel rebars made of 2∅16 mm. For each shear reinforcement scheme, two deep beam samples were tested, one made with plain concrete and the other made with steel fiber reinforced concrete. The results showed that the proposed schemes (inverted U-shape made of angles and steel bars) increased the shear capacity of deep beams by 40.9–75.2% compared to the reference beam without shear reinforcement. In addition to improving the post-peak behavior and ductility, the proposed schemes showed equivalent ultimate shear resistance compared to the reference deep beam made with closely spaced stirrups. The use of steel fiber reinforced concrete in combination with the inverted U-shape angles and steel bars improved the ultimate shear resistance of deep beams and produced a prolonged stable inelastic behavior compared to the reference beam with stirrups. A strut-and-tie model was proposed to predict the shear strength of the deep beams, which showed a strong correlation between the predicted and the experimental results.