CAN/CSA S16

For unsymmetrical flange sections the following equation per SSRC has been implemented to calculate the lateral torsional buckling capacity:

M_{c r} = \frac{ω 2 E}{K_{y} L} [\sqrt{E I_{y} G J} (B_{1} + \sqrt{1 + B_{2} + B_{1}^{2}})]

where

B₁	=	$\frac{π β_{x}}{2 K_{y} L} \sqrt{\frac{E I_{y}}{G J}}$
B₂	=	$\frac{π^{2} E C_{w}}{{(K_{y} L)}^{2} G J}$
β_x	=	$0.9 d^{'} (2 \frac{I_{y c}}{I_{y}} - 1) [1 - {(\frac{I_{y}}{I_{x}})}^{2}]$
d'	=	distance between center of the top and bottom flange
I_yc	=	The moment of inertia of the compression axis about the section minor axis.

The bending capacity of class 3 is considered to be the compression flange section modulus multiplied by the design yield strength.

Channels are designed using the symmetrical provisions of the design specification with the assumption that loading is through the shear center.