Plastic analysis of prismatic compression members in buildings is permitted if (F_y)^½(l/r) does not exceed 800 and F_uless than equal to 65 ksi (448 MPa). For axially loaded members with b/t less than equal to (lambda)_r , the maximum load P _u , ksi (MPa= 6.894 X ksi), may be computed from

P_u = 0.85A_gF_cr

Where A_g=gross cross-sectional area of the member
F _cr =0.658 ^lambda F_y for lambda <= 2.25

=0.877 F_y/lambda for lambda  > 2.25

lambda =(Kl/r)²(F_y/286,220)

The AISC specification for LRFD presents formulas for designing members with slender elements.

The AISC specification for allowable-stress design (ASD) for buildings provides two formulas for computing allowable compressive stress Fa, ksi (MPa), for main members. The formula to use depends on the relationship of the largest effective slenderness ratio Kl/r of the cross section of any unbraced segment to a factor C _c defined by the following equation and table below:
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Based on the American Institute of Steel Construction (AISC) specifications for load-and-resistance factor design (LRFD) for buildings, the shear capacity V _u , kip (kN = 4.448 X kip), of flexural members may be computed from the following:
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