Compression behavior of concrete columns confined by high strength steel wire

Experimental investigations were undertaken on high strength wire (HSW) confined concrete columns. Fifteen columns were tested with the variation of confinement pressure that was achieved by changing the winding spacing of HSW. The stress-strain response, peak strength and strain, ultimate strain, and failure modes of the columns were investigated. The experimental results showed that winding HSW is an effective and efficient method of column jacketing that can significantly increase column strength and ductility. The failure mode of HSW confined concrete columns showed successive fractures of HSW with increased ductility and abundant warning compared with fiber reinforced polymer (FRP) jacketed columns. The test results show that the existing framework for stress-strain modeling of ordinary steel spiral confined concrete columns is generally applicable to HSW confined concrete columns. However, the parameters of the stress-strain model must be revised to suit the significantly different characteristics of the new confining material. Using the test results from this work and other data collected from the literature, an improved stress-strain model is developed which is applicable not only to HSW confined concrete columns but also to ordinary steel spiral confined concrete columns. The proposed model shows an improved performance compared with existing models reported in the literature.