What is considered lateral bracing for a wood stud. 1

[wds1]

I have a 2x6 stud, 10.5' high. When I run the numbers, it can take 5.56k when braced in the weak direction and 0.49k when NOT braced in the weak direction. Can drywall provide the necessary lateral support? If Not, how do they build 2 story houses with walls made of 1/2"dry wall, 2x4 studs, 1/2" rigid insulation, and vinyl siding. A braced 2x4 can carry 2.65k while a unbraced 2x4 can only carry 0.53k.

 

[SlideRuleEra]

When properly attached to the studs, the drywall can provide the necessary bracing. See Paragraph 5.5.2 "Load Bearing Walls", on Page 5-35, of "Residential Structural Design Guide - 2000 Edition" (free .pdf download) at this link

http://www.pathnet.org/sp.asp?id=1442

http://www.SlideRuleEra.net

 

[Pressed]

You have numerous questions and directions there with your note. And to try to just cut through it, have you seen a cut in brace or "wind brace"? A piece of T shaped metal that is installed into a wall for stiffness.

http://www.icc-es.org/reports/pdf_files/BNBC/94-04.pdf

It can be instaled laterally as well.

Balloon framing isn't allowed anymore for multiple stories. It had one stud from top to bottom in a two story house. Now they frame a single story wall with double top plate, add joists and plywood fllor, then start the second story wall just like the first. This is to keep fire from spreading up the cavity that would be there if the walls used one stud from top to bottom.

If this application is required to meet code I suggest you seek a professional in your area. Otherwise there would be not harm in adding lateral blocks/bar for stiffness. But I don't know the whole story of what you have or are trying to do there so my comments may be mute.

Can sheetrock hold some force, yeah. But have you ever seen a nail walk it's way through sheetrock when loaded? I have. Finally, normal framing "studs" don't require special lateral bracing in my experience.



_______________________________________
Feeling frisky.........

http://www.tailofthedragon.com

 

[wds1]

Pressed,
I think you are confusing lateral bracing for Main Wind Force Resisting Systems with lateral bracing to reduce the slenderness ratio. My concern is that I see alot of 2 story houses going up where the lateral support for the studs is provided by 1/2" drywall on the interior and 1/2" rigid insulation and vinyl siding on the exterior. It would be hard to claim lateral support of the stud in the weak direction. Remember a braced 8' 2x4 in the weak direction can carry 2.6k axial load while an Unbraced can only carry 0.5k. Assume we have a typ. 28' wide house with roof trusses. An unbraced stud can only carry 0.5k/(1.33'*14')=.027ksf. 1.33' is the stud spacing and 14' is 1/2 the roof span. That will NOT even carry the roof load, not to mention the 2nd floor and wind loading. They must claim some lateral support. How much and How do they back it up?

 

[rday]

wds1

Yes, the gyp-board (drywall) is assumed to provide weak axis bracing. With the standard 6/12 fastener schedule it is adequate. As far as the 2.6 kip or 5.56 kip number you provide; you need to check crushing in the plate, which is likely the control.

Also note, if the stud is over 10' blocking is required.

Rik

 

[Pressed]

wds

I think you are confused by looking at the pictures. My reply states that a wind brace could be mounted laterally.

Single story studs are 92 5/8" long. Two story studs are 92 5/8" long as well, they are stacked. There is no special lateral support needed for this type of construction (from my experience) and the other two people that responded agree to this. If yours are longer and you are worried, go ahead and install blocks or the wind brace(lateral not diagonal as the picture shows).

Local codes are different from place to place and to be sure a check with a local inspector is probably better for ya.

_______________________________________
Feeling frisky.........

http://www.tailofthedragon.com

 

[madd]

Hi fellas, I'm new here. I'm acting as an owner-builder and got one question about safe maximum loading on temporary 2x4-7' studs stacked together to support 2nd floor and roofing. can you tell me an approx load that can be applied on six (6) 2x4 - 7' studs stacked tightly together? Any information would be great. Thanks. Sorry for hijacking this thread.

 

[AggieYank]

madd. It depends on the type and grade of wood, inconsistencies in the wood, how they are attached so they are "tightly together", what type of load it is (vibrating machine, pallet of drywall, beam above, etc), if the load above is actually all transmitted through the floor to the (6) 2x4s (load path), what the 2x4s are sitting on top of, are they going to be laterally braced in some way, and will the 2x4s be braced by a sheathing such as plywood in either direction or be free standing.

 

[madd]

2x4's are #2 SYP. Three 2x4's are nailed together and another set of three 2x4's nailed together. Both sets of 2x4's are butt up together. Bottom of 2x4's are on top of foundation wall and the top supporting I-beam header. There are no plywood/sheathing or addtional bracing to the (6) 2x4s. The only activity above the studs are normal building of 2nd floor walls and adding trusses. These studs will be removed before drywall being delivered. If these studs can support 10k-15k lbs then I'll be OK! If not then I'd like to know minimum # of 2x4's required for that weight. BTW, the framer initially had (3) 2x4's, I said to add three more! Thanks!

 

[RARWOOD]

Does anyone know a mathematical method to determine if drywall provides sufficient bracing in a studs weak direction.

In general I've assumed that the stud was sufficiently braced if it had drywall on one face. However in the field I've seen garages with load bearing walls braced by Built Rite on one face only. I'm not sure I would want to rely on Built Rite.

 

[madd]

Whoops, I was wrong about the load. The load I posted are both live and dead loads. Plus I don't have bricks, windows, drywall, etc in yet. So the load would be around 6000 lbs.
I would not depend on drywall for bracing. Why not add blockings between studs and use plywood/osb sheathing?