Experimental Axial Compressive Behavior of Partially Confined Concrete Columns with Combined External and Internal FRP Strips

Abstract

Current researches have demonstrated that the partial confining design by discrete strips is a promising and economic alternative to the full strengthening technique. In this connection, this study consists to evolve a new sustainable technique for confining concrete columns under axial compression. The proposed design technique consists to embed discontinuously hexagonal fibers reinforced polymer (FRP) strips and wrapped the outer concrete partially using external circular FRP strips. A detailed experimental program was realized on standard dimension composite-encased concrete cylinders under compressive loading until failure to evaluate the axial compressive strength and the corresponding failure mode of the reinforced concrete. In addition, mechanical characterization tests were performed to provide the behavior laws of used raw materials. The emphasized experimental results namely: stress versus hoop and axial strain curves and the rupture patterns of all tested samples indicate clearly an improvement on the stiffness, axial stress and strain of the reinforced concrete columns compared to conventional unconfined ones.

Keywords

• Axial behavior
• Experimental; Hexagonal FRP strips
• Partially confined-concrete.