A model for the stress-strain relationship of rectangular confined normal and high strength concrete columns

Abstract

In this paper an analytical model is developed to predict the complete stress-strain relationship of normal and high strength square and rectangular short columns confined with rectilinear hoops, cross ties, and combinations of different types of lateral reinforcement. The confinement pressure is assumed to be uniform within the core of the column. The internal force equilibrium, the properties of the materials, and the geometry of the section are used to evaluate the lateral pressures. The model utilizes a fractional equation which gives a realistic description of the behaviour of the confined sections. Comparisons are made between the predictions of the model and the available experimental results. The model demonstrates good predictive capability for a variety of cross-sectional shapes and configurations of longitudinal as well as lateral confinement reinforcement. The effects of different parameters, such as the concrete strength, the amount of confining steel, and the configurations of the longitudinal as well as lateral reinforcement, on the behaviour of the confined columns are presented and discussed.