Cold-Formed Steel Design

[WD7]

What programs or references are recommended?

Curious if a hat section about 4" deep is stronger in bending with the top fibers in tension or compression?

 

[Ltwine]

Check metal deck institute, or cold formed steel institute for technical information.

It really depends on how the supports are arranged, and the sheetings laid - continuous over several supports, or simply supported between two.

 

[JAE]

AISI for cold steel design:

http://www.steel.org//AM/Template.cfm?Section=Home

 

[WD7]

Actually the hat section will be used for a curved rafter section with purlins spaced about 4' apart along the length of the member.

This also brings up the unbraced factors Lx,Ly, and Lt. If the purlins are 4' apart, are the unbraced lengths all equal to 4'? The roof covering will be a fabric or polycarb covering with 4-6' spacing between rafters.

Thx

 

[ash060]

Is the 4" section holding something up like a roof or just there for the ceiling support?

 

[WD7]

The hat section is holding the fabric covering, but it will have to withstand snow and wind loads that will be applied to the fabric and then distributed to the rafters.

 

[MikeHalloran]

Try CUFSM, free software that may be helpful:

http://www.ce.jhu.edu/bschafer/

Mike Halloran
Pembroke Pines, FL, USA

 

[NearBeer]

FWIW...

Kind of off topic but I went to a short course on cold formed steel design put on by the Univ. of Missouri

http://www.ccfssonline.org

3 day course, intensive, and got a free textbook out of it. I think it is offered twice a year.

/R,

NearBeer

 

[DHKpeWI]

The CFS program is excellent and can be downloaded for free at

http://www.rsgsoftware.com.

 

[ash060]

I would recommend something that is a little more stout if it has to resist snow and wind loads.

Hat Channels are generally for furring and ceilings (non-structural)

 

[ajh1]

Comment to NearBeer:
I would agree with your assessment on the Short Course.
However, it is an every odd year offering, alternating with an International Cold-Form Steel Conference in St. Louis in the even numbered years.

 

[WD7]

I am using RAM Advanse for analysis and then transferring the forces to the CFS software to compare results. The results seem to be significantly different with differences up to 10% for the code check. Is there a way to figure out the values RAM automatically calculates for the Cb and Cm factors? When I calculate them by hand, the results still vary (quite a bit) even though the same spec is used.

Also, how are the Saint-Venant torsion (J) and warping constants (Cw) calculated?

Does anybody use the CFS or RAM software fairly regularly for cold formed design? If so, do you have any recommendations or tips for the software? Thx

 

[UcfSE]

Have you looked in the comprehensive reports RAM Advanse offers for each designed members?