New Approach for Modeling Confined Concrete. I: Circular Columns

Abstract

An analytical stress-strain model for concrete confined by spiral steel was developed. The model is based on the concrete–spiral steel interaction. The deformational behavior of concrete under axial and lateral compression provided at discrete locations was studied experimentally, and the response characteristics of spiral to lateral expansion of concrete was determined theoretically. A total of 24 (145 × 300 mm) confined concrete cylinders were tested to failure under monotonic concentric compression. A criterion for maximum axial strength and a set of constitutive relations for estimating the characteristic points on the stress-strain curve of confined concrete were derived. A comparative study was performed on the response of concrete cylinders tested in the present study and of 15 large-size circular columns tested by other researchers. The proposed model gave good agreement with the test results.