Shear tests of reinforced concrete beams with continuous rectangular spiral reinforcement

The behaviour of reinforced concrete shear-critical beams with rectangular cross-section and continuous rectangular spiral reinforcement as transverse reinforcement under monotonous loading is experimentally investigated. Further, an advanced rectangular spiral reinforcement that has shear-favourably inclined vertical links is also presented and tested as shear reinforcement. The experimental program includes eight (8) beams. Test results clearly indicate that the use of rectangular spiral reinforcement provided enhanced bearing capacity and improved shear performance in the examined beams. Beams with spiral reinforcement spacing at 120 mm and 80 mm exhibited 14.9% and 14.7% increased shear capacity with respect to the corresponding beams with stirrups, respectively. Furthermore beams with advanced spirals spacing at 120 mm and 80 mm exhibited 17.2% and 21.7% increased shear capacity with respect to the corresponding beams with stirrups, respectively. Moreover, the beams with advanced spirals exhibited deformation ductility values 2.10 and 2.60, respectively, demonstrating this way improved post-peak deformation ductility compared to the beams with equal quantity of commonly used stirrups.