Mechanical performance of a confined reinforced concrete beam

This study focused on the four-point bending behavior of the concrete beam subjected to an innovative internal axial confinement process. An experimental study was carried out to validate the effectiveness of this technique. The four-point bending tests was carried out on confined concrete beams by this technique which makes it possible to produce an induced a compression stress induced by the normal component of the tensile effort developed in the resistance reinforcement at the level of the anchoring of steel bars. The results show the increasing of the ultimate bending strength compared to the control beam. Two opposing half-cylindrical plates are welded to the level of the curvatures of the steel bars. Each bar has a hook at one end only. The two hooks are arranged in the taut area of the beam and diametrically opposite. This technique allows us to mobilize the confining stresses from the beginning of loading of the beam, contrary to the existing methods, without using other materials as a composite FRP. Furthermore, a theoretical study was proposed to predict the equivalent load to be applied to the reference concrete beam when it is subjected to an ultimate bending moment determinate in the confined concrete beam. The experimental and theoretical results confrontation shows a good agreement.