Hysteretic Behavior of R/C Columns Confined with Opposing Spirals

Abstract

This paper investigates the cyclic behavior of reinforced concrete circular bridge columns confined using a new confinement technique. The new confinement technique uses two opposing spirals (cross spirals) to confine circular bridge columns in order to enhance their strength and ductility or to increase the spiral spacing (pitch) to facilitate construction. Twelve reduced scale reinforced concrete columns with two different lengths and several spiral spacings were tested. The columns were subjected to constant axial load (bridge self weight) and reversed cyclic lateral displacement (seismic load) to study the influence of the new confinement technique on the lateral strength and ductility of reinforced concrete columns compared to conventional single spiral confinement. Six of the columns were designed to study the flexural behavior, and the other six columns were designed to study the shear behavior. This paper reveals the effect of the new confinement technique on the cyclic behavior of reinforced concrete circular bridge columns.