Slenderness value in steel design

[meenz27]

Hello, I'm working on roof truss design and now facing a trouble 'bout instability which is the slenderness check of steel sections. 2 attached images show my doubt about kL/r ratio which is extremely high. From images i got the values of ky, Ly and ry which are 1.0, 11.0 m. and 6.0 cm respectively. Hence ky*Ly/ry should be 183.33 isn't it?

So how can i solve it?

Thank you

[Artur.Kosakowski]

Please check if the value of axial force is not above the critical level. If this doesn't answer your question attach the file please. Thank you.

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.

[meenz27]

Thank you for reply. So, i attach the file and hope you will solve my ploblem. I found something in the verification formula when i take a manual calculation follows that formulas. Some parameters are zero which make errors in that formulas.

Pls figure out what i found.

Thank you for help.

Here is the link (Can't attach because file size is large)

http://www.mediafire.com/?g99ukd877gz6n34

[Artur.Kosakowski · Accepted solution]

Please download and install SP4 and HF 5 for Robot 2013 from:

http://usa.autodesk.com/adsk/servlet/ps/dl/index?siteID=123112&id=2334435&linkID=13140816

Mind the select the correct files (Robot Professional vs. Standard and 32 vs. 64-bit).

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.

[meenz27]

The problem has fixed. Thanks for help.

[dinawagdy11]

Hi Artur,

I'm facing the same issue now with Robot 2019. What should I do?