Enhancing concrete column performance: a comparative study of full vs. partial CFRP confinement techniques

This study evaluates the effectiveness of full and partial fiber-reinforced polymer (FRP) confinement techniques on concrete columns, with a focus on carbon fiber-reinforced polymers (CFRP). Experimental results revealed that full CFRP confinement markedly improves both compressive strength and ductility. Specifically, columns fully confined with CFRP exhibited a maximum increase in compressive strength of 89.36% compared to unconfined specimens. In contrast, partial confinement using horizontal strips with a 30 mm spacing resulted in a 49.53% increase in compressive strength, though this was 21.03% less than that achieved with full confinement. Spiral confinement, with spacings of 45 mm and 65 mm, achieved strength increases of 3.03% and 6.58%, respectively, with a maximum enhancement of 21.90% compared to unconfined concrete. Deformation results showed that horizontal strips enhanced ultimate axial deformation by up to 610.78%, whereas spiral confinement improved deformation by 591.42% at 30 mm spacing. The study concludes that horizontal CFRP strips provide superior performance and efficiency for strength enhancement compared to spiral confinement. These findings indicate that partial CFRP confinement is a viable alternative to full confinement, offering substantial improvements in concrete strength and deformation while optimizing material use and installation complexity.