Strengthening of Eccentric and Concentric Reinforced Concrete Columns Using CFRP Sheets with and without Confinement: A Numerical Study

Strengthening reinforced concrete columns (RCC) has become an essential technique due to its critical role in existing structures rehabilitation. The behavior of RCC strengthened with fiber-reinforced polymers (FRPs) was assessed by performing a numerical study. Carbon fiber-reinforced polymer longitudinal sheets (CFRPs), which are externally bonded (EB), were suggested for the proposed technique. Furthermore, two alternatives were explored in this study: with or without confinement using CFRPs. Additionally, four different parameters were studied, including the area of fiber (Af), confinement percentage, eccentricity (e), and steel reinforcement ratio (As %). Sixty-seven (67) RCCs were idealized and simulated using a three-dimensional finite element program called ANSYS v. 2022 R2. The numerical results were validated against three published experimental and analytical data sets found in the literature. The research concludes that strengthening with both longitudinal and transverse FRP reinforcement can enhance columns’ axial and flexural behaviors. In the case of axial loading without eccentricity, heavy confinement significantly improves column capacity by almost 61%, whereas in the case of eccentricity, strengthening can improve the column capacity by 40%. Moreover, a remarkable increase in column ductility is achieved through strengthening with confinement.