Ultra-high performance steel fibers concrete corbels: Experimental investigation

In the present paper, results of testing eleven ultra-high performance steel fibers concrete (UHPSFC) corbels with concrete compressive strength 150 MPa and under vertical loading are reported. The main test variables were shear span-to depth ratio, main tension reinforcement ratio and the provision of secondary reinforcement (closed stirrups). In all corbels, except one, the main steel bars yielded before failure and corbels failed in a consistent manner. Whereas the validity from provision the secondary reinforcement in the UHPSFC corbels represents by a significant increase in the corbels stiffness with taking into consideration the corbels failure modes. The test results in terms of load versus deflection curves, stiffness, ductility and crack patterns show the effectiveness of using ultra high performance steel fibers concrete to ensure a superior strength and deformation capacity in reinforced concrete corbels. Experimental results have been compared with diverse prediction methods. The truss model can provide accurate strength predictions in comparison with the ACI 318-14 cod's procedure.