Concrete Constitutive Model for NLEE Analysis of Structures

Abstract

A simple constitutive model for ‘smeared cracking’ nonlinear finite element analysis of reinforced concrete structures is described. The model divides the uniaxial response curve for concrete into fivedamage regions, described as linear elastic; compressive strain hardening; compressive strain softening; tensile strain softening; and tensile stiffening regions. Recommendations for incorporating strain localization effects into homogenized material properties in the softening regions are given. The effect of biaxial stress conditions on peak strengths is represented by a variation of the Kupfer‐Hilsdorf failure curve in stress space, in which the compressive and tensile envelopes are separately specified. Recommendations for the effects of tensile cracking and confinement on the shear modulus and the compressivesoftening modulus, respectively, are included. The central thrust of the paper is to incorporate those attributes of the constitutive model which affect the prediction of structural failure modes as the nature of thestructures varies.