An experimental study on spiral columns

Abstract

In this study, minimum confinement reinforcement requirement of spiral columns under combined bending and axial load was investigated. Since the object of this study was to test the equation proposed by Ersoy and Ozcebe [1] experimentally and to report the results comprehensively, twelve spiral column specimens were tested under combined bending and axial load [2, 3]. Six specimens were designed according to one of the equations used in the Turkish [4] and ACI (American Concrete Institute) codes [5] and the other six specimens were designed according to the proposed equation. The variable parameters used in this study were the volumetric ratio of spiral steel (calculated by the code and the proposed equation), the ratio of the gross concrete area to the confined core area and the yield strength of the spiral steel. Test results of the columns designed according to the current Code equations, based on the axially loaded column behavior, are compared with the test results of the columns designed according to the proposed equation, based on the eccentrically loaded column behavior.