Experimental Behavior of RC Columns, Confined with Stirrup and Strips, Under Cyclic Axial Load

Abstract

This paper presents the experimental behavior of columns confined with passive steel strips instead of standard deformed stirrups. Three types of steel strips having width with thickness ratios as 7.5, 12.4 and 18.8 were used. To compare results stirrup with 6.35 mm in diameter were also used as confining reinforcement. Cross-sectional area of each strip was kept the same and was equivalent to 6.35 mm diameter deformed bars. All the columns were tested under cyclic axial load and behavior of columns, in terms of performance of hooks and stress–strain relationship, was compared. It was found that strength of column increases as width to thickness ratio increases. However, when width to thickness ratio of strips increases from 12.4 to 18.8, the resulting increases in strength decreases. It was also found that the technique used to provide hooks to the strips needs improvement.