Improving the structural behavior of shear-deficient RC deep beams using steel fibers: Experimental, numerical and probabilistic approach

The transverse reinforcement of reinforced concrete deep beams is vulnerable to corrosion under harsh environments leading to shear-deficient beams. The use of steel fibers in the concrete mix during casting can enhance the shear capacity of such shear-deficient beams to the extent that the beams can overcome their loss of shear resistance. In the present study, following experimental, numerical, and probabilistic approaches, the role of steel fibers in improving the structural behavior and shear capacity of shear-deficient deep RC beams is studied, and an optimum quantity of steel fibers for achieving the desired safety level is proposed. During the experimental study, six full-scale shear-deficient deep beams having varying percentages of steel fibers (0, 0.5, and 1%) were cast and then tested under quasi-static monotonic displacement-controlled four-point loading. The finite element-based numerical study was carried out under the same experimental loading regime. Probability-based reliability analysis was then carried out to obtain an optimum quantity of steel fibers for the desired reliability. The results of the above three investigations show that the steel fibers can be successfully employed for substantially enhancing the ductility, crack pattern, shear strength, load-displacement behavior, and reliability level of shear-deficient deep beams.