Cold formed steel

[McGill10]

Hello,
I am new for Cold formed steel design field.From previous posts on similar topics in this forum, I find lots of good information.Still have few questions and would appreciate any help:
-the project I am talking about is one story building with CFS framing: what will be the best selection for roof framing: bar joist or Cold Formed Steel truss?.The roof will be monosloped. I don't see Dietrich catalog on truss,who is the commonly used MFR on truss.
-What is the common practice for Header/jamb design: designing a built up section or using HDS or similar assembly from Dietrich.As I see dietrich has pre-fabricated assembly of heavy duty studs for header and jamb.
-is there any reference material that shows a complete design of CFS framing building.I don't have the CFS design manual-does this cover most of itmes and worth bying?
thanks a lot in advance.

 

[dik]

What is the roof span... that will likely determine the use of OWSJ vs. CFS... What is the roof construction?

Dik

 

[homostructural]

Yes, the span of the roof will definitely determine if a truss is needed!
Which design standard do you have to use?

Check this list with design examples. Some of them are for the design of basic cold-formed structural elements (beams, columns etc).

All about Eurocodes:

http://www.DesignToEurocodes.com

 

[McGill10]

Roof typical span is 25 ft. The roof construction is metal deck with insulation. Code to be followed is AISI North American Specification for cold formed steel based on IBC 2006. I am thinking truss will be more economical than C or Z section.

 

[hokie66]

The choice of system would be dependent on where you are located in the world. As you referred to IBC, I assume US or Canada. In those countries, bar joists would be the usual solution, as steel joists are essentially a commodity, not requiring individual design. On the other hand, it you were in Australia, cold formed sections would probably be the system of choice, as bar joists are scarce and cold formed purlins are treated as a commodity. For a 25' span, C or Z sections would be used...too much labor in fabrication of trusses.

 

[johnbridge231]

Do you perform your design according to Eurocode or other regulation?


Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[Bagman2524]

Cold Formed Steel Design by Wei-Wen Yu is a good reference for design Cold Formed Steel Structures.

 

[haynewp]

Z or C cold-formed individual members should be pretty cheap if you don't have unusual loads, the span falls in a typical pre-engineered building bay length.

I have seen jamb and header shapes by the Steel Network and Dietrich used instead of built-up members. You could probably count on better quality if using the proprietary jamb rather than specifying a built-up section and relying on the installer to connect the members according to your drawings.

The AISI manual and their several other publications have examples. I don't know of one that goes through a complete building example though.

 

[PeterDias]

Hello all,

At moment I have working in a company that is apllying the construction methode of light steel framing and i need a programe who helps me to make and analyse de structures, make output designs and calculate de forces. Somebody can give me the link for the steel smart system? The steel network site seem's to be always down.

Thanks,

Peter Dias

 

[McGill10]

Peter dias,

The link for Steel Smart is below, I haven't come accros server down problem- have not used the sofrware yet but seems very impressive:

http://www.steelsmartsystem.com/site/LSFDetails.aspx

share your experience in Cold formed design.
thanks

 

[McGill10]

Hello All,

I have two more questions to all about little more specific details on CFS framing System:
1) Parapet Detail in CFS framing system. How the parapet detail look likes.The Ht of parapet is 3ft, and my question is do we provide kicker at top of parapet stud or we cantilever parapet stud.

2) As the structure of roof will be sloped requiring varying height of studs which seems little hectic for construction.What's your experience on these? How better is to make roof structure flat and taper the insulation any limits on that.

Your thoughts will be Greatly appreciated.

thanks.

 

[UcfSE]

1. Do either that works. A 3-foot cantilever should not be difficult.

2. Tapered insulation is ok if the maximum insulation thickness is not excessive. Too much and you won't be able to find screws long enough to attach the insulation to the deck, not to mention it increases your loads. CFS framers can deal with varying stud heights without much issue, though they won't like it.

 

[McGill10]

For Parapet framing, the kicker option is ruled out by Arch.
Now the remaining option being cantilever parapet .As the wall studs stop below roof and the parapet studs start from there as a two separate members. What is the best connection to make the parapet stud as a cantilever member ?.I am thinking using straps on both flanges and connecting the studs(above and below) to make a moment connection.


Any thoughts/suggestions appreciated.

 

[UcfSE]

If your studs are interupted to form the parapet, I would provide some hot-rolled steel at a wide spacing to form the cantilever, and let the cfs studs be infill. Straps won't do a very good job providing the stiffness you need to restrain the deflection, imo.