wood stud bracing - gyp board?

[cf2]

I am designing a structure built with two wood double stud walls. The interior wall is load bearing. Would it be reasonable to assume that the gyp board could brace the studs out of plane? I am assuming I would have to spec a minimum panel size and connections.

Thanks!

 

[asixth]

What is the size of the studs and at what spacing. I'll assume they will be something like 4"x2" at 12 or 18" centers. When calculating the compressive capacity of the wall studs, I would not assume that the plasterboard restrains the studs out of plane.

 

[cf2]

The studs are 2x4 at 24" on center. The architect is using advanced framing and wants to minimize wood use as much as possible. That is why I wanted to look at bracing with gyp. I cannot decrease the stud spacing.

 

[mijowe]

I like to specify stud blocking for weak axis bracing of the studs. In cases where a building is three or four stories, the dead weight and construction loads on the building will load these studs, and in most cases this will be there long before drywall is added to the studs.

Also, if i understand you correctly, you have a double 2x4 stud wall, typically used for sound isolation. In this case you will only be sheathing one side of the stud.

I do think i have seen limits for bracing steel studs by sheathing, so some information may be out there.

 

[asixth]

I went through the numbers on a timber stud using the wood design code in my region and would not be using the 2x4" studs to take anymore than 10kN (2.2kips) dead and live load. This is with restraint at 10' and noggin at 5'.

 

[BAretired]

What's noggin?

BA

 

[asixth]

See framing diagram, may just be local terminology

 

[cf2]

Thanks for your thoughts! And yes, construction timeline is a good thought. I think we'd still be ok... It's a 2 story building with concrete on the upper floor. (the exterior wall is sheathed and takes seismic and wind, the interior wall only has gyp and is load bearing. we may add gussets between the walls, like a larsen truss, for wind).

I think we'll add "noggin"/blocking at the center of studs or go to 2x6.

Thanks!

 

[hokie66]

The blocking is "nogging", "noggin" is your/my blockhead.

 

[apsix]

Known as a 'dwang' by our Kiwi friends.

 

[asixth]

I row of nogging is always good. I have never used a timber stud to support a concrete slab. I would be concerned about the compressive capacity of the timber stud. I would much prefer using corefilled cmu.

 

[DaveAtkins]

I have never seen any Code that says you can't assume wood studs are braced by GWB. And as I recall, GWB on one face is adequate for bracing.

DaveAtkins

 

[abusementpark]

For the construction timeline reasons outlined by mijowe, I like to only consider gypsum wall board as providing flexural bracing for exterior (i.e. due to wind/lateral load), but not compressive bracing due to gravity loads.

 

[BAretired]

Well, dwang! I should have used my noggin.

A few years ago, I was amazed to see three story apartments with floors and roof of hollow core slabs and wood stud bearing walls in Winnipeg, Manitoba. Apparently it is a common system there. I did not like it then and still do not.

Our code specifically says that a wood stud may be considered braced in the weak direction by gypsum wallboard applied on one side only.

BA

 

[cf2]

I should have been more specific regarding the concrete. It's a 2" topping slab over the plywood. Still adds significant weight unusual to a wood framed building.

 

[shobroco]

Canadian codes, like most codes, recognize GWB on one side only of wood studs as sufficient restraint . 2" of concrete floor topping is not significant enough to change that.

Nogging in our area is an historic term meaning brick or mortar infill between the studs (pugging if it is between the joists). I have restored buildings with it, but never seen it done in a modern building. It was intended to provide insulation, sound-proofing, & a measure of fire protection, but it also provided lateral support to the studs.