F8Round HSS

This section applies to round HSS having $D / t$ ratios of less than $\frac{0.45 E}{F_{y}}$

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

F8.1 Yielding

(F8-1)

F8.2 Local Buckling

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

(F8-2)

• (c) For sections with slender walls

(F8-3)

where

$\begin{aligned} D & =\text { outside diameter of round HSS, in. (mm) } \\ F_{c r} & =\frac{0.33 E}{(D)}\end{aligned}$ (F8-4)

$t \quad$ = design wall thickness of HSS member, in. (mm)