Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	Design
	Subarea:	American Steel Design
	Original Author:	Bentley Technical Support Group

The KL/ry reported for a double angle does not match my hand calculations. I am designing the section per the AISC ASD 9th edition code.

For singly symmetric shapes such as Tees and Double Angles, the KL/r value for the Y axis is calculated by STAAD using the rules for flexural torsional buckling as explained in page 3-53 of the AISC ASD manual. It is not calculated as Ky multiplied by Ly divided by ry.