Incorrect Section - slenderness ratio

[Anonymous]

Dear Sirs,

I'm working on this model which is a steel structure on the roof of a building.

When I run the analysis I get an "Incorrect Section" error when I see the code check of some steel beams on the roof of the structure, it happens because of the slenderness ratio.

Actually all those beams are restrained by the purlins, which I do not show in the model.

Is there any way to say to Robot that the top flange of the beams are restrained?

Thanks, kind regards.

Giacomo

[Artur.Kosakowski · Accepted solution]

Actually all those beams are restrained by the purlins, which I do not show in the model.

You may indicate their positions using the internal bracings dialog.

Is there any way to say to Robot that the top flange of the beams are restrained?

See the attached picture (the corresponding settings is marked in red)

I'd recommend watching the recording of the 3rd Robot webinar on steel design available from:

http://forums.autodesk.com/t5/robot-structural-analysis-forum/robot-structural-analysis-webinars/td-...

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[Anonymous · Accepted solution]

Hi Giacomo,

yes of course.

You just have to go to Steel/Aluminium design -> Steel/Aluminium member type -> create a new type -> fill the fields you want and activate lateral buckling analysis -> click on upper flange (or lower as you prefer) -> choose intermediate bracings -> insert the position of the bracings in the following field:

[Anonymous]

Thanks! I followed the instructions and everything is ok now. 🙂

[Anonymous]

Thanks Artur! I'll watch the video today to get to a better understanding. I solved the issue, by the way 🙂