Applies To
	Product(s):	STAAD.Pro
	Version(s):	ALL
	Environment:	ALL
	Area:	Design
	Subarea:	American Design Codes
	Original Author:	Abhisek Mandal, Bentley Technical Support Group

 

What is Ix in staad American cold form members. If Ix is polar momemnt of inertia then it will be Iz+Iy. but values are showing very less compared to Iz and Iy.

 

IX in STAAD for American cold formed members are equivalent to J (capital J) which is known as St. Venant's torsion constant. It is different from polar moment of inertia. All the formula and above mentioned data is available in AISI manual part 1. Please refer to the document to know all the formula for different shapes in details.