A constitutive model for analysis of reinforced concrete solids

Abstract

This paper describes formulations intended to expand the applicability of the modified compression field theory for general three-dimensional analysis of reinforced concrete solids.The modified compression field theory, which was specifically developed from tests on cracked reinforced concrete panels, has primarily concentrated on describing the stress-strain response of reinforced concrete under compression and tension stress states.Recent work has been directed at refining finite element programs based on the modified compression field theory for problems in which confinement and lateral expansion effects are important.Proposed stress-strain relationships are based on an orthotropic nonlinear elastic model that acknowledges the asymmetric response of concrete under multiaxial stress conditions.Lateral expansion of concrete subjected to compression is modelled under all stress states.The formulation accounts for complex behaviour such as concrete strength enhancement due to confinement, concrete strength degradation due to transverse cracking, tension stiffening, and crack slip.The models assume short-term, monotonic loading conditions.A sample analysis of a reinforced concrete shear wall is presented to illustrate the improved modelling with the consideration of lateral expansion and confinement effects.