Damage Effect on Concrete Columns Confined with Carbon Composites

Five experimental cyclic tests were carried out on reinforced concrete (RC) rectangular columns with rounded corners, different conditions (new and damaged), and different strengthening systems, which included confinement through carbon fiber-reinforced polymer (CFRP) jackets, anchor dowels, high-strength repair mortar, and external longitudinal stainless steel bars. Lateral load-displacement relationship, energy dissipation, ductility, and curvature results were analyzed with two different damage assessment classifications. The overall evaluation concludes that confining RC columns with external CFRP is both viable and improves performance by itself and combined with other techniques. Damaged columns that were retrofitted showed an increased load capacity up to 20% along with good ductile behavior within the limits of the United States, European, Canadian, and Japanese codes, with minor/moderate degree of damage at 1% drift ratio and moderate degree of damage at 2% drift ratio.