The equivalent axial tensile load Pe, which produces an average axial tensile stress in the section equivalent to the combined stress due to axial tension P and bending M, at the extreme fibre of the section, is given by (where Z is the section modulus of

The equivalent axial tensile load Pe, which produces an average axial tensile stress in the section equivalent to the combined stress due to axial tension P and bending M, at the extreme fibre of the section, is given by (where Z is the section modulus of the section).