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Re: 16d Common vs 16d Sinker vs 16d Short

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Ah,yes the old "sinkers" vs "common" debate

Yes in a perfect world everything would be built per plan & at least
you'd be getting what the designer had specified  but.......

would that be the "best"  (or at least, the better structure)?

imo (& experience) the 16d common (.162 dia x 3.5") is a rather burly
nail, sure to split wood much more frequently than a sinker

Many years ago (~10)  I did a series of tests comparing the
performance of Simpson MST48s nailed into 4x6 timber as inter storey
ties.   Sinkers (16d)  vs commons (16d).....................

the sinkers reliably (100% of the time) developed the straps to strap failure
the commons typically failed the system by causing the timber to split
wide open before reaching strap ultimate

When the commons did not cause splitting failure, they provided a
stiffer system but considering all the tests, the commons yielded a
variety of failure modes with an accompanying larger spread of
strength values.

Simpson finally figured this out (after years of calling out 16
commons for strap installation)
I don't have the Simpson catalog memorized but they do call for
sinkers in some applications.   additionally, their nail spacing is
rather close,   jmho

imo  .162 dia is just too big a nail to drive into most common framing
members w/o causing damage.   So unless predrilling is going to be
done, a  nail dia of .148 seems to be a good compromise, .131 is
getting pretty skinny though

Quoted nail values are all well & good but what happens to them when
the wood splits?



cheers
Bob



On 7/19/05, Gary Grinstead <Gary.Grinstead(--nospam--at)ci.stockton.ca.us> wrote:
> It has come to my attention that virtually all houses in my area are using 16d sinkers instead of the 16d commons typically specified on the plans.  Additionally in some instances 16d shorts are being used.  The nail sizes are as follows:
> 
> 16d common = 3-1/2" x 0.162"  diameter
> 16d sinker = 3-1/4" x 0.148" diameter
> 16d short = 3-1/4" x 0.131" diameter
> 
> There is no way I'd accept a 16d short which has less than 70% of the capacity of the 16d common.  My question is about the 16d sinker which has about 84% capacity.  Is the general feeling that a combination of (1) factor of safety on capacity, (2) conservative live loads, and (3) additional nailing (calc'd to 3.4 nails --- use 4 nails) will make up for the shortfall or is this something you'd call the contractor on?
> 
> Gary Grinstead, SE
> Plancheck Engineer
> City of Stockton, CA
> 
> 
> 
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