cruciform column consisting from "I" shaped profiles

[engco]

I have a problem with the design of cruciform column consisting from "I" shaped profiles. Should I consider the them as two parts and consider only the part which is in the bending direction or add the weak axis strength of the other part?? I don't know exactly which part of the code (LRFD)i should use..(F1 to F12)

and also i wonder the axial load design...if there any writings or source for an example calculation, i'd appreciate much..thanks for your help..

 

[phuduhudu]

I did the same recently. I guess you mean an I section with it's flange against the web of another I section. I would consider it as a built up section and work out the Moment of Inertia and the Elastic Modulus of the combined section. I don't know anything about US codes but to be safe I would design it using only the elastic modulus as it is not a very compact section any more. Then you have to ensure that they are connected enough to allow sharing of forces evenly.

Carl Bauer

http://www.bauerconsultbotswana.com

 

[sdz]

I agree mostly with carlbauer. That assumes the sections are welded together. You might have to consider slenderness of the various elements to guard agains local buckling.

 

[frv]

If you are actually building this from rolled "w" shapes, then you don't need to worry about slenderness.

See Section E4 (b) (i) of AISC 13th Ed.

 

[swearingen]

Cruciform shapes also bring up the limit state of flexural-torsional buckling, where they twist on their own axis.



If you "heard" it on the internet, it's guilty until proven innocent. - DCS