Time-Dependent Tangent Modulus Applied to Column Creep Buckling

The relation of the time-dependent tangent-modulus load—as conceived by Shanley—to actual column capacity is clarified. It may be interpreted as a limiting case of the “allowable-load capacity” which has been shown to be a conservative estimate. The time-dependent tangent-modulus load is, therefore, an approximation to a conservative estimate. The approximation, however, may be either conservative or nonconservative when applied to imperfect or real columns. Typical cases are discussed and experimental results for two alloys are cited.