Enhancing load capacity of reinforced concrete columns using high strength concrete and fiber reinforcement

Strengthening of structural elements is sometimes necessary for architectural purposes to withstand additional loads without cross-section enlargement. This study evaluates the structural performance of reinforced concrete columns toughened using high-strength concrete, steel fiber concrete of 1% volume fraction, and near-surface mounted NSM steel or carbon fiber reinforced polymer CFRP bars. Five columns of 0.15×0.15×1 m were cast and axially loaded till failure. The investigational consequences revealed that a load-carrying capacity and stiffness augmented by 55.1 and 91.1% when the compressive strength is 1.5 times the normal with a ductility decrease of 28.2% whereas steel fiber concrete raised them by 34.3, 6.4, and 11.6%. In addition, NSM steel or CFRP bars exhibited ultimate loads and stiffness 13.6 to 29.7% and 17.2 to 21.7% higher than the non-strengthened column. However, the ductility decreased by 2.5 to 12.4%.