# D1.J.2.3 Stress Due to Compression

The allowable compressive stress on the gross section of axially loaded compression members is calculated based on the formula 3.2.2-1 in the API Code when the largest effective slenderness ratio, Kl/r is less than or equal to C_{c}. If Kl/r exceeds C_{c}, then the allowable compressive stress is increased as per formula (3.2.2-2) of the Code.

Where:

${C}_{c}=\sqrt{2{\pi}^{2}\frac{E}{{F}_{y}}}$

For D/t > 60, the lesser of F_{xe} or F_{xc} is substituted for F_{xy}.

Where:

- F
_{xe}= the elastic local buckling stress calculated with C, the critical elastic buckling coefficient = 0.3 (3.2.2-3) - F
_{xc}= the inelastic local buckling stress. (3.2.2-4)