Effect of Slenderness Ratio on Confined Reinforced Concrete Columns Using NSM-CFRP Rope

Abstract

The need for the flexible near-surface-mounted carbon fiber–reinforced polymer (NSM-CFRP) material has recently been used as a strengthening material for structures. Therefore, this experimental work and finite element analysis studies were carried out to assess the behavior of confined rectangular columns using NSM-CFRP rope. Nine RC columns with three slenderness ratios (17.78, 24.44, and 28.89) including the spacing between ropes were investigated under concentric compression load. The obtained results revealed that the NSM-CFRP significantly contributed to the load capacity of RC columns. Furthermore, the role of the spacing between ropes in improving the load capacity of confined rectangular RC columns was observed. The load capacity increased by decreasing the spacing from 200 to 100 mm between ropes by 133.1%–149.7%. The improvement in the load capacity of columns when the slenderness ratio decreases were recorded. The percentage of load capacity was approximately 124.5%–139.7% and 112.3%–133.1% when using slenderness ratios of 24.44 and 28.89, respectively. The failure mode for all strengthened specimens was dominated by spalling and crushing of concrete followed by NSM-CFRP rope rupture. A numerical model was developed using ABAQUS software for NSM-CFRP rope–confined columns accounting for material nonlinearities. The results showed a good agreement between the experimental work and numerical model results.