FLEXURAL BEHAVIOR OF HIGH-STRENGTH RC COLUMNS CONFINED BY RECTILINEAR REINFORCEMENT

Abstract

A comparative study of stress-strain curve models for confined concrete proposed by authors and other researchers is conducted at the first phase of the investigation described in this paper. Five models are applied to predict the results of specimens, which were tested under concentric axial load only, as well as under combined axial load and bending moment without moment gradient. It is concluded that the authors' model predicts test results better than the other models studied. The proposed stress-strain curve model is applied to predict the flexural behavior of the plastic hinge regions of the columns under axial load and bending moment with moment gradient (shear) at the second phase of the investigation. The emphasis is placed on estimation of the flexural strength of columns made of high-strength concrete. A semi-empirical formula to estimate the flexural strength of concrete columns is proposed from the viewpoint of practical design.