Shear capacity investigation of self compacting concrete beams with rectangular spiral reinforcement

Replacing traditional closed stirrups by rectangular spiral reinforcements in concrete beams constructed using self compacting concrete (SCC) is experimentally investigated in this paper by testing twenty beams under static loading. The shear performance of SCC beams is evaluated by measuring the maximum shear load values, load-deflection curves, and crack propagation for all tested beams. Two different spirals spacing of 200 and 150 mm and five different angles of inclination for the spiral reinforcement (85°, 80°, 77.2°, 75°, and 72.5°) are adopted. The experimental shear capacity results are compared with theoretical shear strength determined by the (ACI 318) code. The results indicated that using of continuous spiral reinforcement improves the shear capacity of SCC beams up to 16.67% increase in comparison to traditional closed stirrups. Moreover, the results showed that optimum performance depends on the angles of inclination, where 85° was the optimum angle of inclination regardless of pitch spacing. It is recommended to use the continuous spiral reinforcements in SCC beams because it enhances the shear capacity, and reduces time and labor cost needed in construction.