Behavior of Square RC Short Columns with New Arrangement of Ties Subjected to Axial Load: Experimental and Numerical Studies

Reinforced concrete columns consume large quantities of ties, especially inner cross-ties in columns with large dimensions. In some cases, nesting of the pillars occurs as a result of the presence of cross-ties. The main objective of this paper is to develop new methods for transverse reinforcement in RC columns and investigate their effect on the behavior of the columns. The proposed V-ties as transverse reinforcement replacing the ordinary and cross-ties details are economically feasible. They facilitate shorter construction periods and decrease materials and labor costs. For this purpose, experimental and numerical studies are carried out. In the experimental program, nine reinforced concrete columns with identical concrete dimensions and longitudinal reinforcing bars were prepared and tested under concentric axial load with different tie configurations. The main parameters were the tie configurations and the length (lv) of V-tie legs. As part of the numerical study, the finite element model using the ABAQUS software program obtained good agreement with the experimental results of specimens. A numerical parametric study was carried out to study the influence of concrete compressive strength and longitudinal reinforcement ratio on the behavior of RC columns with the considered tie configurations. Based on the experimental and numerical results, it was found that using V-tie techniques instead of traditional ties could increase the axial load capacity of columns, restrain early local buckling of the longitudinal reinforcing bars and improve the concrete core confinement of reinforced concrete columns.