LAUSR

Abstract Biaxial and triaxial compression tests were performed on 100 × 100 ×100 mm cubic specimens of concrete under different stress loading rates. All the tests were performed using a true triaxial testing machine. The analysis of the data revealed that the intermediate principal stress, hydrostatic stress and shear stress are the main factors influencing the failure criterion for concrete under multiaxial stress. Based on the twin shear strength theory, three failure criterion models were developed. The five-parameter model A considers the shear strength as the main factor, the five-parameter model B considers hydrostatic strength as the main factor, and the six-parameter model considers both the shear strength and hydrostatic strength. The parameters for these failure criterion models have clear physical significance and form the failure criterion in a theoretical analysis. Models A and B apply to different stress states and show similar results. The six-parameter model can apply to most stress states, but the computed results depend on the boundary conditions. This convenient model can also be extended for nonlinear analyses of concrete under multiaxial stress in compression.