A Model of the Confined Concrete in High-Strength Reinforced Concrete Tied Columns

Abstract

An experimental and analytical study was conducted to develop the confined concrete model of reinforced high-strength concrete tied columns subjected to monotonically increasing concentric axial compression. Twenty-one large-scale columns (260 X 260 X 1200 mm) of high-strength concrete of 50 MPa and 85 MPa were fabricated to simulate full-size structural members. The effects of the main variables such as the concrete compressive strengths, tie configurations, amount of the transverse reinforcement, tie spacing and the spalling of the concrete cover were studied in this research programme. More confinement is required in columns of high-strength concrete than in columns of low-strength concrete to achieve the same degree of strength enhancement. The proposed model satisfactorily predicted the experimental stress-strain behaviours for the confined high-strength concrete up to 100 MPa.