Abstract
Practical expressions of Failure Criteria of structural light-weight and normal-weight concrete under combined compression and torsion were investigated. Consequently, the following empirical formulas in terms of F_<sp> and F_<cy> were obtained for the faiure criteria of the above mentioned concretes; [numerical formula] or [numerical formula] or [numerical formula] where, F_<cy> : compressive strength, σ_1, σ_3 : principal stresses, F_<sp> : tensile splitting strength, σ_y : axial compressive stress, σ : normal stress, τ_<xy> : torsional shearing stress. τ : shearing stress,
