Effect of ply configuration on hollow square reinforced concrete columns confined with Carbon fibre-reinforced polymer (CFRP)

This paper presents results of testing twelve hollow square reinforced concrete specimens wrapped with Carbon fibre reinforced polymer CFRP. The effect of ply configuration on the behaviour of the specimens is investigated. All specimens were 800mm high and had the dimensions of 200mm×200mm in cross-section and a hollow core of 80mm×80 mm. The specimens were divided into four groups with three specimens each. The specimens in the first group without bonding CFRP served as references. While the remaining three groups of specimens were externally wrapped with CFRP in three different ply configurations of hoop, vertical and 45◦ angle with reference to the circumferential direction, respectively. The specimens in each group were tested as columns under three eccentricities (0, 25, and 50 mm). Experimental results show that all types of wrap configuration increased the strength of reinforced concrete columns. The columns wrapped exclusively with hoop configuration proved to show the greatest ductility properties.