This paper deals with the effect of steel fiber amounts and the interaction between the fiber amount and stirrup ratio on the shear behavior and capacity of reinforced concrete (RC) deep beams with steel fibers. The experimental program was carried out on twelve deep beams with different fiber amounts (0, 30, 40, and 65 kg/m3) and stirrup ratios (0.1, 0.15, and 0.25%). The test results have shown that the use of steel fibers increased the shear resistance (up to 55%), reduced the shear crack width (up to 11 times) and deflection (up to 57%) of the tested deep beams. Also, it was found that using unsuitable steel fiber amount and stirrup ratio would reduce the efficiency of the fibers in a deep beam due to the interaction between the fibers and stirrups. Increasing the stirrup ratio in a deep beam with a high amount of steel fibers can reduce the efficacy of the fibers in enhancing the shear capacity of the beam. The most cost-effective steel fiber amount was found to be around 30 to 45 kg/m3.
Keywords:
steel fibers; deep beam; shear capacity; fiber amount; stirrup ratio.
Effect of fiber amount and stirrup ratio on shear resistance of steel fiber reinforced concrete deep beams
