Fundamental Specifications for Steel Construction/Compression

• ${\displaystyle P_{n}=F_{n}A_{e}}$

For ${\displaystyle F_{y}/F_{e}\leq 2.25}$

• ${\displaystyle F_{n}=(0.658}$^{(${\displaystyle F_{y}/F_{e}}$)})${\displaystyle F_{y}}$

For ${\displaystyle F_{y}/F_{e}>2.25}$

• ${\displaystyle F_{n}=0.877F_{e}}$

• ${\displaystyle F_{e}}$ = π²E/(KL/r)²

• ${\displaystyle F_{c}r}$ = flexural buckling stress (ksi, MPa)
• ${\displaystyle F_{e}}$ = elastick buckling stress (ksi, MPa)
• ${\displaystyle F_{y}}$ = specified minimum yield stress (ksi, MPa)
• ${\displaystyle F_{u}}$ = specified minimum tensile strength (ksi, MPa)
• ${\displaystyle A_{g}}$ = gross area of cross section (in², mm²)
• ${\displaystyle A_{e}}$ = effective net area of cross section, as reduced for holes and/or local buckling effects (in², mm²)