G5Round HSS

AISC 360-22, Specification for Structural Steel Buildings

Last Updated 29 Oct 2026

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The nominal shear strength, $V_{n}$ , of round HSS, according to the limit states of shear yielding and shear buckling, shall be determined as

V_{n}=F_{c r} A_{g} / 2

(G5-1)

where

$F_{c r}$ shall be the larger of

$F_{cr} = \frac{1.60 E}{\sqrt{\frac{L_{v}}{D}} \left( \frac{D}{t} \right)^{\frac{5}{4}}} (G5-2a$

F_{c r}=\frac{1.60 E}{\sqrt{\frac{L_{v}}{D}}\left(\frac{D}{t}\right)^{\frac{5}{4}}}

(G5-2a)

$Mathematical Formula Equation: $F{cr} = \frac{0.78E}{$

Figure description:

Mathematical Formula

Equation: $F_{cr} = \frac{0.78E}{(\frac{D}{t}^{\frac{3}{2}}}$
Reference Label: (G5-2b)
Variables (from context:
- $F_{cr}$ : Critical stress
- $E$ : Modulus of elasticity
- $D$ : Outside diameter
- $t$ : Design wall thickness

F_{c r}=\frac{0.78 E}{\left(\frac{D}{t}\right)^{\frac{3}{2}}}

(G5-2b)

but shall not exceed $0.6 F_{y}$ $A_{g}=$ gross area of member, in. ${ }^{2}\left(\mathrm{~mm}^{2}\right)$ $D=$ outside diameter, in. (mm) $L_{v}=$ distance from maximum to zero shear force, in. (mm) $t \quad=$ design wall thickness, in. (mm)

User Note: The shear buckling equations, Equations G5-2a and G5-2b, will control for $D / t$ over 100, high-strength steels, and long lengths. For standard sections, shear yielding will usually control and $F_{c r}=0.6 F_{y}$ .