COMPLETE TRIAXIAL STRESS-STRAIN CURVES FOR CONCRETE.

A method to predict the ascending and the descending parts of the stress-strain curve of concrete subjected to triaxial compressive stresses is presented. The proposed analytical stress-strain relationship depends on the values of the three principal stresses and strains at the ultimate compressive strength. A criterion to predict the triaxial compressive strength is proposed, which is sensitive to all three stress invariants. To enable predictions of the post-peak stress-strain relation, experiments were conducted on concrete confined by steel tube.