Primer on Cold-Formed Steel Lateral Systems

[Simba13]

Morning all,

I've been trying to read up on how cold-formed steel lateral systems work and I admit I'm a little confused. In some ways it seems like a timber stud wall with light gauge studs instead of timber studs and tracks instead of top and bottom plates and so my mind goes to sheathing/shear walls. But I've also seen braced frames online and looked at Simpson's walls. Is there a good resource to help wrap my mind around cold-formed steel lateral systems? Rather than specific details at this point, I'm more interested in getting the general sense of the lateral load path.

Thanks,

 

[DaveAtkins]

AISI S213-07/S1-09 (2012). This is the North American Standard for Cold-Formed Steel Framing - Lateral Design.

DaveAtkins

 

[Simba13]

DaveAtkins Very nice, I'm reading through it. This is basically what I was looking for, Thanks!

 

[phamENG]

Simba - you're quite right. Light gauge metal framing and standard stud walls are both light framing methods and have similar lateral solutions. DaveATkin's reference is a good one - I have it on my shelf and use it every time I do a light gauge project.

Nearly all of the options available to wood shear walls are also available to light gauge. You can sheath it in plywood or gypsum and use it as a shear wall. But you can also use light gauge steel sheets and get some pretty robust shear walls. This may be what you mean by "similar to simpson walls." Then again, Simpson has a light gauge Strong-Wall option. Where wood walls have let-in braces, light gauge have straps that can be used to form in plane bracing. In larger buildings, lateral systems are occasionally replaced by structural steel shapes as it gets easier/cheaper than building up several heavy "light" gauge members.

 

[Simba13]

phamENG Alright, I think it's making sense. Looking at sheathing specifically, just trying to think this through a bit. With Table C2.1-3 it goes through the capacities of different sheathing with different fastener spacings. It seems basically the same as the table out of the SDPWS albeit with screws instead of nails (it even has the aspect ratio reduction factor). That's fine and makes a lot of sense. But what if I wanted to do a perforated shear wall with hold-downs on either end. My understanding is that headers acts to form the continuous load path over openings, is there an equivalent of a header in light-gauge metal framing? And secondly, if you use sheathing, is it continuously sheathed just like a perforated wood shear wall/wood structural panel?

 

[phamENG]

A wall with openings falls under "Type II" shearwall if I remember correctly.

 

[skeletron]

This document:

https://nvlpubs.nist.gov/nistpubs/gcr/2016/NIST.GCR.16-917-38.pdf

And there was a recent corresponding webinar about lateral systems with cold-formed steel. It was quite high level, but was helpful in introducing the concepts.

 

[DaveAtkins]

A wall with openings falls under "Type II" shearwall if I remember correctly.

Yes, you remember correctly. Type II is their terminology for a perforated shear wall.

DaveAtkins