RE: "J" For Lateral Torsional Buckling equations

Assuming J is the Torsion Constant. Then for open sections approximately

 

J = sum( bt^3/3)

 

Where b = length of element

           T = thickness

 

For special case of  circular section J equals the polar second moment of area.

 

Regards

Conrad Harrison

B.Tech (mfg & mech), MIIE, gradTIEAust

mailto:sch.tectonic@bigpond.com

Adelaide

South Australia