Design-Oriented Analysis of Slender RC Columns Strengthened with Longitudinal High Modulus CFRP Laminates

This paper investigates the effectiveness of high modulus fiber reinforced polymer (FRP) composites for strengthening of slender reinforced concrete (RC) columns. Most research on strengthening RC columns using FRP composites has focused on the confinement issue of the concrete section; however slender RC columns may suffer overall buckling failure at loads much lower than their counterpart short columns. This paper is focused on using an analytical model based on modifying the provisions of ACI 318-08 to develop the loath path of the slender columns. Using the load paths and cross-sectional axial load-bending moment interaction curves, the interaction curves of the slender columns are developed. Moreover, through a parametric study, the effectiveness of CFRP laminates is evaluated for different slenderness ratios, CFRP reinforcement ratios, and effective length factors. It is shown that the longitudinal CFRP reinforcements are more effective on slender columns.