Study of Shear Strength Resistance in Confined Concrete Beams

Abstract

High strength concrete provides high strength than a normal concrete but less ductility. Over-reinforcing the concrete beam tends to lower the ductility which lead to structures fail without good warning. In order to avoid these kinds of brittle failures Euro codes and other standards does not allow designers to over-reinforce the concrete beam. Even though the code does not allow over-reinforcing, sometimes the designers may need to over-reinforce the beam due to certain limitations. Therefore, the purpose of this research is to increase the ductility of the beam by introducing helical reinforcement in the compression area.

In this research is to study the behavior of reinforced concrete beams with a single and double steel helical confinement in the compression zone. The investigation will be about the flexural behavior of the confined the reinforced concrete beams with respect to ultimate shear strength. The reinforced concrete beams were under-reinforced with a provided steel ratio of (ρ 0.866%) for the first sets of beams and (ρ 1.29%) for the second set of the beams. By using a high strength concrete of f_ck= 60N/mm²

In this research, the six under-reinforced high strength RC beams dimensions of 200 mm (width), 300 mm (height) having 2000 mm in length with a clear span of 1700 mm that is divided into three categories control beam, single and double confinement beam having same pitch but different steel provided ratio. From this experiment, it expected that the confined concrete beams will have a higher flexural strength and enhanced the shear strength compare to the controlled beams.