CFS Lateral Bracing 2

[BSVBD]

I've used this detail for 20 years:

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1473886312/tips/CFS_-_LATERAL_BRACING_krmcgc.pdf[/url]

The general contractor said, "What is the purpose of the steel stud lateral bracing? I understand interior wind loads and using the channel stiffeners but do we really need to screw clips at every stud connection? This seems more for load bearing walls."

Lateral bracing is to prevent the studs from twisting. I tend to agree that clips at EVERY stud seems to be overkill for partition walls. Can i lighten up on this?

Any suggestions or comments?

Thank you!

 

[KootK]

I think that your choices are:

1) Require the channel and connect to all studs OR;

2) Don't provide the channel.

In a typical interior application with dry wall on both sides, I don't think that you need the channel except, perhaps where the studs continue above the drywall. I don't think that it makes sense to brace some studs in a wall but not others though. The unbraced ones would be, well... unbraced obviously.

I've run into some oddball situations where I wasn't allowed to count on sheathing as bracing for reasons of fire protection. That's rare though and has always been on exterior walls.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[sandman21]

If you to get the moment capacity of the metal studs you would need to have the bracing. If you want to make it easier for the contractor consider using, Simpson Bracing or similar connector.

 

[BSVBD]

Koot... i believe, if every other stud were NOT braced by the u-channel, if the partition has wallboard each side, since ALL studs are fastened with DW-screws, wouldn't THAT provide contributory / tributary bracing. Similarly, if you provide blocking to only a few spaces, if half the joists can't fall, when sheathed, none can fall or twist!

Koot... have you ever specified partition walls without channel brace? Why else would you provide choice #2? I can't imagine not specifying ANY lat-brace...

sandman... I've not seen those brace clips before. Thank you!

 

[KootK]

Koot... i believe, if every other stud were NOT braced by the u-channel, if the partition has wallboard each side, since ALL studs are fastened with DW-screws, wouldn't THAT provide contributory / tributary bracing.

I see the logic but I've never felt compelled to do it this way. And I'm not familiar with any references that detail this method as a valid bracing scheme. That said:

1) I'm hardly a CFM wizard and;

2) From my perspective, once's you've got the sheathing, you're done anyhow.

Koot... have you ever specified partition walls without channel brace?

Well yeah, that's pretty much all that I do unless the studs continue substantially higher than the sheathing. See the exerpt below from Clark Dietrich's website.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[sandman21]

we have a note for interior partition conditions which states that if the wall has sheathing, gyp. etc. each side the bracing is not required.

 

[wannabeSE]

That's a pretty typical detail when there isn't gyp (or other sheathing) on both sides except is usually 4' max spacing (I work with a lot of 14' - 18' floor to floor heights). When the studs get bigger than 6", it is common to see flat straps on each face with blocking at 8' OC max. See SSMA Details. Clark Dietrich has similar clips to Simpson

http://www.clarkdietrich.com/products/bridging-bracing-backing-connections/fastbridge-clip-fb43-fb68

 

[XR250]

For interior, non gravity load bearing applications of normal proportions, I don't see the need as the sheetrock should provide proper restraint. I will always show it on interior (or exterior) gravity load bearing studs as the sheetrock may be removed at some point causing instability.
I am conflicted on normal height exterior curtainwall studs - not really because I think it does anything, but because everyone else shows it

 

[DaveAtkins]

I think--but do not know for sure--that the reason for using bridging in all stud walls (loadbearing and non-load bearing) is twofold:
* Stability of the studs during construction, prior to the GWB or other sheathing being applied
* The possibility of the sheathing deteriorating over time (think water softening up exterior GWB over a period of years)

DaveAtkins

 

[tolchijb]

All valid points, but if the drawings indicate the bridging requirement the contractor should have bid it with the bridging and should install it per the drawings. Unless he is going to pass on the savings to the owner (never happen), you are just helping him increase his profit at the expense of your liability since you are reducing the requirements relative to the CD's. In the future you could revise your detail, but for this project I would stick to the drawings as bid.