Constitutive Model for Confined High Strength Concrete Subjected to Cyclic Loading

The paper presents a constitutive model developed for high strength concrete with uniform lateral confinement subjected to cyclic axial compression. It is based on the testing program carried out for normal and high strength concrete. Compressive strengths of concrete at the time of testing were 44, 58, 83, and 106 MPa. Uniform confining pressures applied were 4, 8, and 12 MPa. The stress–strain model presented in this paper was developed based on triaxial test results, which were obtained under well-controlled conditions, where direct measurement of axial and lateral strains were possible. Ability to predict the axial as well as lateral strains in confined concrete is a superior attribute of the proposed model. When concrete is analyzed for passive confinement (such as the one provided by reinforcement), estimating the lateral strain is important because the lateral confinement directly depends on it. The proposed model can be used for modeling high strength concrete in seismic analysis of structures, where confining of concrete by reinforcement is essential for ductility.