A common concern when checking flexural buckling of a channel section under axial load, is what radius of gyration should be used to calculate Fex and Fey?
In S16-14 Clause 13.3.2, the elastic buckling stresses are given by:
For singly-symmetric sections such as channels, the same clause specifies that the y-axis is taken as the axis of symmetry. But when using the tables of properties and dimensions for channels in Part 6 of the Handbook of Steel Construction, the x-axis is defined as the axis of symmetry. Therefore, Fex should be calculated using the radius of gyration ry as given in the Handbook tables, and likewise Fey should be calculated using rx.