Research On Stability For Axially Compressed Hot-Rolled Single--Angle Members

Hot-rolled angles are classified as equal and unequal angles. An equal angle section, being a singly-symmetric section, will buckle in a torsional-flexural pattern about any axis except for flexural buckling about the unsymmetric axis. Being an unsymmetric section, an unequal angle section is torsional-flexural buckling. In active code for design of steel structures, axially compressed members are calculated not as torsional-flexural buckling but as flexural buckling with equivalent slenderness ratio, residual stress and initial geometry imperfection are also taken into account as flexural buckling. Although this can avoid the complicated calculation, it is difficult to calculate a member precisely and safely because the influence of imperfection for torsional-flexural buckling is not same as the one for flexural buckling. In this paper, torsional-flexural buckling of single-angle members is researched deeply and systematically by ultimate strength theory and general FEM analysis software ANSYS, and is contrasted with some codes, as a result the simple and practical formulas for stability coefficient are recommended for design purpose.