Generalized Stress-Strain Relations for Concrete

Triaxial experimental data on the behavior of concrete have indicated that while only volumetric changes occur under pure hydrostatic stress, both distortional and volumetric changes occur under pure deviatoric stress. By analyzing these data and assuming that such experimental data in general can only be relied upon to represent the material behavior up to the level at which continuous cracks begin to form within the structure of the material, it has been possible to express mathematically the deformational characteristics of concrete in terms of the bulk and shear moduli and a correction function that allows for volume changes unde deviatoric stress. These expressions have been formulated to be consistent with use in computer-based methods of structural analysis and they completely define the state of strain corresponding to any state of stress.