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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 Cc. If Kl/r exceeds Cc, then the allowable compressive stress is increased as per formula (3.2.2-2) of the Code.


C c = 2 π 2 E F y

For D/t > 60, the lesser of Fxe or Fxc is substituted for Fxy.


  • Fxe = the elastic local buckling stress calculated with C, the critical elastic buckling coefficient = 0.3 (3.2.2-3)
  • Fxc = the inelastic local buckling stress. (3.2.2-4)