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Re: 3/8 inch shear panels

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Can't resist getting my $0.02 worth in.  The UBC requires that all nailing
spaced 2 in. o.c. must be in staggered rows; e.g., two rows with nails
spaced 4 in. o.c. in each row.  Splitting of framing is avoided with this
pattern.  Also applies to 10d nails spaced 3 in. o.c.  At vertical joints
where panels butt on the same stud, the framing must be 3 in. nominal to
accomodate the two rows of nails on each panel edge.

We have run some cyclic load tests on shear walls with above provisions and
results support code values (585 plf for one case, 600 plf for another),
with load factors of 2.2 or higher compared to 97 UBC values.

More info will be discussed at Wood Solutions Fair in Long Beach on 9/30.
Be there and be square!

John Rose/APA,Tacoma

Robert Kazanjy wrote:

> Yes, the design load on the hd is about 5 to 6 kips but the ultimate
> load is about 12 to 15 kips; not an insignificant load but not an
> unreasonable load.  Your footing & connection has to be able to handle
> the ultimate loads.   Shear is no problem but uplift/pullout might be.
>
> If you've got to use 3/8 STR I with 8d @ 2"  maybe you're "stretching"
> the envelope.  How about using more reasonably nailed walls (8d at 3" or
> 4")  {These work great I've tested LOTS of them}and adding another one.
> Or a longer wall.  IMO 8d @ 2" is asking for trouble.
>
> There is nothing wrong with 3/8" plywood shear walls properly designed &
> detailed.  Just use reasonable nailing schedules.
>
> Reference June 1998 EERI paper - Cyclic Load Testing of Woof-Framed,
> Plywood Sheathed Shear Walls Using ASTM 564 and Three Loading Sequences.
> All the plywood was 3/8 & all the nailing was at 3" oc.  (Unfortunately
> units in the paper are metric).  While you at take a look at SEAOC 1995
> & 1996 Annual Convention Proceedings >>>>> lots more plywood panel test
> data.
>
>  Robert Kazanjy, PE  **Disclaimer: I speak for myself not UC-Irvine**
>  Senior Development Engineer
>  Civil & Environmental Engineering
>  UC Irvine
>  E4130 EG,  Zot: 2175
>  rkazanjy(--nospam--at)uci.edu
>
> Lynn wrote:
>
> > EphHirsch(--nospam--at)aol.com wrote:
> >
> > > 730 plf ?!!!  What are the hold-down forces on such a wall panel?
> >
> > Well, if the shear panel was 4 feet long, and 8 feet high, the uplift
> > would be
> > around 5,000 to 6,000 lbs.  An average sized hold down is all that is
> > required.
> >
> > > And even if
> > > a hold-down is found from a catalog (or special designed) to resist
> > such a
> > > force, what resists the hold-down itself? (That's probably a lot of
> > concrete
> > > footing dead weight required.)
> >
> > It does not take a lot of footing and slab to come up with 6,000 lbs.
> >
> > > The sill bolts figure to be pretty significant
> > > too.
> >
> > Hmm, well 3/4" dia bolts at 16" o/c. in a 3x sill plate would probably
> > work fine.
> > No big deal.
> >
> > > Regrdless of what the code in question allows, such a force and
> > nailing
> > > pattern are pretty questionable, even if legal.
> >
> > Really!  Well, I can tell you it is very common.  In our office we do
> > not use 3/8"
> > plywood anymore, but a unit shear of 730 plf is very common.  I hope
> > you were not
> > thinking something like "KIPS" per lineal ft.  That would certainly be
> > a problem.
> >
> > Lynn
> >
>