Strength Behavior of High Strength R/C Columns under Biaxial Bending-Shear and Varying Axial Load

Twelve short square R/C columns using high-strength concrete were tested to examine the effects of biaxial bending-shear force and varying axial load on the shear and flexural strength behavior. The columns were cyclically deflected either along their transverse principal axis to produce uniaxial bending-shear or along their diagonal to produce biaxial bending-shear. For columns failing in flexure, the experimental results were found to be in close agreement with the computed values given by the AIJ Code, regardless of the differences of concrete strength, biaxial bending-shear and varying axial load. For short columns subjected to low compressive or tensile axial stress, the computed ultimate shear strengths by the 1988 AIJ Design Equation overestimated the test results. The shear test results were in best agreement with the computed values by the "Kuramoto-Minami\u27s Ultimate Shear Design Equation" proposed in 1990