Experimental behavior of concrete columns confined by welded wire fabric as transverse reinforcement under axial compression

An experimental study was carried out to investigate the behavior of normal-strength concrete short columns confined by welded wire fabric (WWF) as transverse reinforcement under monotonically increasing concentric compression. The parameters studied in this research included the volumetric ratio, spacing and lateral steel configuration, and distribution of longitudinal steel around the core perimeter or longitudinal reinforcement ratio. The effects of these variables on the uniaxial behavior of reinforced concrete columns are presented and discussed. The performance of columns laterally reinforced with WWF was compared with that of columns laterally reinforced with conventional ties. The results indicate that WWF can be effective in confining the core concrete, resulting in significant improvements in the strength and ductility of columns. Strength increases of at least 17% and ductility increases of 130% were observed when compared with the corresponding specimens with conventional ties. An increase of longitudinal reinforcement and decrease of transverse reinforcement spacing effectively improved the ductility of confined concrete columns. Columns with four longitudinal reinforcing bars exhibited much less ductility than columns with eight or 12 longitudinal reinforcing bars. In addition, welded grids can be useful to reduce the congestion of reinforcement and improve the concrete quality in the members. Experimental observations and results of tests on 22 short concrete columns reinforced with longitudinal steel and WWF or conventional ties under axial compression are presented herein.