F6I-shaped members and channels bent about their minor axis

This section applies to I-shaped members and channels bent about their minor axis.

The nominal flexural strength, $M_{n}$, shall be the lower value obtained according to the limit states of yielding (plastic moment) and flange local buckling.

F6.1 Yielding

M₁ = M₁ = F,Z, ≤ 1.6F,Sy (F6-1)

where

$S_{y}=$ elastic section modulus taken about the $y$-axis, in. ${ }^{3}\left(\mathrm{~mm}^{3}\right)$

$Z_{y}=$ plastic section modulus taken about the y-axis, in. ${ }^{3}\left(\mathrm{~mm}^{3}\right)$

F6.2 Flange Local Buckling

• (a) For sections with compact flanges, the limit state of flange local buckling does not apply.

User Note: For Fy = 50 ksi (345 MPa), all current ASTM A6/A6M W, S, M, C, and MC shapes except W21×48, W14×99, W14×90, W12×65, W10×12, W8×31, W8×10, W6×15, W6×9, W6×8.5, and M4×6 have compact flanges.

(b) For sections with noncompact flanges

(c) For sections with slender flanges

(F6-3)

where

(F6-4)

$b=$ for flanges of I-shaped members, half the full flange width, $b_{f}$; for flanges of channels, the full nominal dimension of the flange, in. (mm)

$t_{f} \quad$ = thickness of the flange, in. (mm)

$\lambda=\frac{b}{t_{f}}$

$\lambda_{p f}=\lambda_{p}$, the limiting width-to-thickness ratio for a compact flange as defined in Table B4.1b

$\lambda_{r f}=\lambda_{r}$, the limiting width-to-thickness ratio for a noncompact flange as defined in Table B4.1b