Cracking for Torsion

[dcarr82775]

I know there is a general Ig modifier for concrete beams. Is there a way to tell RISA the section cracked for torsion? I tried adjusting Ig, but I didn't see a significant change in the member torsions.

 

[JoshPlumSE]

The Icracked factors affect flexure, not torsion. RISA doesn't give you a direct way to manipulate the torsional stiffness of concrete members.

That being said, what about just modifying the G value for the concrete material? This will affect shear stiffness as well, so there could be some additional affect on your structure. But, shear stiffness may be a small contributor compared with the flexural stiffness of the member.

Also, if this reduction only applies to certain members, you can create a new concrete material and only assign it to these members.

 

[dcarr82775]

Good idea. It worked well enough. Thanks