Experimental behavior of circular concrete columns under reversed cyclic loading

This paper experimentally investigates the cyclic behavior of reinforced concrete circular columns confined using a new confinement technique. The new confinement technique uses two opposing spirals (cross spirals) to confine circular columns in order to enhance their strength and ductility or to increase the spiral spacing to facilitate the flow of concrete during construction. Twelve cantilever circular columns with two different lengths and several spiral spacing and patterns were tested. The columns were subjected to constant axial load and reversed cyclic lateral displacement to study the influence of the new confinement technique on the lateral strength and ductility of circular columns compared to columns confined with conventional single spiral. Six of the columns (1000 mm high and 200 mm diameter) were designed to study the flexural behavior, and the other six columns (500 mm high and 200 mm diameter) were designed to study the shear behavior.