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RE: 3x studs in (E) stud wall (Remodel)

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Why doesn’t the code allow use of 3x studs for bearing?

 

Is it because cannot guarantee transfer of force into all three members? Is it a problem of cutting the ends square to bear against the plates, or a problem of composite action of the three lamina? If the three members truly behave as a single member, then cutting the end square is no different than cutting the end of a solid piece of material. Glue laminating is probably better in this respect than nail laminating. Nail laminating the studs on site is potentially a poor way of getting both a built up stud and square end.

 

In similar manner for the use of 3x studs in the shear wall: can the required forces be transferred into all three studs? What affect does it have if the forces are not transferred into all 3 studs?

 

When the wall frame racks over, then the 2 or 3 lamina of the built up studs will slide one over the other. When fasten the sheathing how many of the studs will it be fastened to? One sheet may be fastened to one stud, and the adjacent panel fastened to two studs. Other than dove tailing the sheathing I don’t see how sheathing on either side of the stud can be fastened to all three studs: 2 out of the three at the most. This suggests only using one of the studs in a shear panel, and only considering individual panels. That is don’t treat as perforated shear wall unless have continuity.

 

That’s my guess.

Regards

Conrad Harrison

B.Tech (mfg & mech), MIIE, gradTIEAust

mailto:sch.tectonic(--nospam--at)bigpond.com

Adelaide

South Australia


From: erik gibbs [mailto:erik.gibbs(--nospam--at)gmail.com]
Sent: Thursday, 6 March 2008 14:51
To: seaint(--nospam--at)seaint.org
Subject: 3x studs in (E) stud wall (Remodel)

 

We are working on a remodel where the existing 2 story home was built sometime in the early 1920's. All the walls, including exterior are 2x flat studs. The architect is calling for (N) windows in the (E) exterior walls and now we need to provide new shearwalls. The problem is that we would like to keep the wall thickness as minimal as possible. We are thinking of using 3x studs next to the (E) 2x flat studs and turning the (E) walls into shearwalls.

 

Does anyone have any idea if 3x studs are allowed to be used in shearwalls of an existing structure?

 

I know that the code does not allow 3x studs for exterior bearing walls, but in this case the (E) stud walls are already there. we are just using the 3x's for shear purposes.

 

Any info or feedback would be greatly appreciated.

 

Erik Gibbs