Empirical Models for Confined Concrete under Uniaxial Loading

Abstract

Theoretically sound empirical models for the axial stress-strain behavior as well as the transverse deformation behavior of concrete with constant confinement under uniaxial compression loading are proposed based on plasticity theory using existing empirical models and test data in the literature. The proposed axial stress-strain model provides strength and ductility increases with increasing confining pressure. The confining pressure is applied in the model as an initial hydrostatic compression loading region. The proposed empirical transverse deformation model uses the plastic strain rate as a function of the axial strain to provide a basis for quantifying the compaction and dilation behavior of confined concrete under uniaxial loading conditions. Concretes with various compressive strengths are considered in combination with confining pressures up to 50% of the unconfined concrete strength. Parameters needed to describe the axial and transverse deformation behaviors are identified and their recommended values are provided.