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RE: Plywood shear panels / box nails

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Ray,
Time makes issues of the past fuzzy so here is what I recall:
 
1. There is a difference in shear capacity of box nails and commons. Common nails, if I recall, have a thicker shank and larger head area which contributes to the increase shear capacity as noted in the UBC nail capacity tables.
 
2. I vaguely remember the testing done by Ficcadenti and my memory recalls that it was done prior to the publication of the SEAOSC standards for Cyclic testing which would have made Ficcadenti's cyclic tests unacceptable.
 
3. Although this is a rumor, it was my understanding from other sources that Ficcadenti's results, like the paper he wrote about eccentric blocking for shear transfer, was done as an expert witness representing one of the sides of the argument. This makes the results questionable. As I recall (and again this is only from memory and should be verified rather than taken as fact) Ficcadenti's paper on eccentric blocking which was published by SEAOC in "Proceedings" (the SEAOC Annual Publication) was published without review or comment. It created some stir as to how easy it was for an opinion paper to be published so as to gain credibility in the professional community. The wood committee chairman at the time issued a disclaimer indicating that the paper did not represent the opinion of SEAOSC or the Wood Committee members.
 
I would tend to base my opinions on the difference between Box nails and Commons from the technical documents produced by APA, which was rather extensive. The City of Los Angeles required a reduction of shear by 15% if box nails were used in lieu of Commons. While it is true that Box nails were used at one time in nail guns, it is my understanding that Commons have been available for nailing guns for some time. While shank diameter is important in bending and shear strength of the nail, you can't neglect the surface area of the head of the nail as this will reduce pull-though and crushing of the panel edge.
 
Check with APA on their studies done with Common verses Box nails. I believe it is pretty intensive and should help you.
 
Regards,
Dennis S Wish, PE
-----Original Message-----
From: RShreenan(--nospam--at)aol.com [mailto:RShreenan(--nospam--at)aol.com]
Sent: Sunday, May 20, 2001 4:31 PM
To: seaint(--nospam--at)seaint.org
Subject: Plywood shear panels / box nails

Hi structural intellectuals and sport fans:

Is it reasonable to assume that box nails perform as well as common nails in
plywood shear panels within the deflection limits required by the Uniform
Building Codes prior to 1997 (.005h)
?  Has there been any cyclic testing done
recently in that regard?  I have the test results done by Seb Ficcadenti and
there does not appear to be an appreciable difference but there seems to be a
difference of opinion amongst structural engineers as to whether the proper
test protocol was used in the testing procedure.  I was also told by many
that the SEAOC did not accept the results as being valid, but I don't know
for what reason.

It seems that 8-10 years ago and prior most wood framed residential projects
with plywood shear walls and diaphragms were nailed with gun nails that were
box nails.   

I would like your opinions on this issue or any sources of information on
documented cyclic test results on plywood shear panels nailed with box nails.

Thanks in advance.

Ray Shreenan SE