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nails in withdrawal to resist wind uplift?

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Title: nails in withdrawal to resist wind uplift?

Scott,

There is nothing in the NDS(r) to that effect, except for 2001 NDS 11.2.3.2 which states that "Nails and spikes shall not be loaded in withdrawal from end grain of wood." Also, note that Table 10.3.3 of the 2001 NDS shows reductions of 75% for nails in withdrawal in wood that will have moisture content fluctuating above or below 19% in-service vs. time of fabrication.

In general, you'll want to load nails laterally to resist uplift if possible. Case-in-point is our Wood Frame Construction Manual (WFCM) for One- and Two-Family Dwellings, 2001 Edition, which contains prescriptive solutions for roof to wall, wall to wall, and wall to foundation uplift connections. In each case, they are handled by 1-1/4"x20gage ASTM A653 Grade 33 steel straps, with enough nails loaded LATERALLY to resist the uplift loads.

However, note that in the case of roof and wall sheathing, nails must be loaded in withdrawal to resist suction loads. So, Tables 3.10 and 3.11 of the WFCM tabulate maximum nail spacing for sheathing causing withdrawal loads on nails.

HTH

Buddy

John "Buddy" Showalter, P.E.
Director, Technical Media
AF&PA/American Wood Council
1111 19th Street, NW, Suite 800
Washington, DC 20036
P: 202-463-2769
F: 202-463-2791
http://www.awc.org

The American Wood Council (AWC) is the wood products division of the American Forest & Paper Association (AF&PA). AWC develops internationally recognized standards for wood design and construction. Its efforts with building codes and standards, engineering and research, and technology transfer ensure proper application for engineered and traditional wood products.

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The guidance provided herein is not a formal interpretation of any AF&PA standard.  Interpretations of AF&PA standards are only available through a formal process outlined in AF&PA's standards development procedures.

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Subject: nails in withdrawal to resist wind uplift?
From: "Haan, Scott M POA" <Scott.M.Haan(--nospam--at)poa02.usace.army.mil>
To: "Seaint(--nospam--at)Seaint.Org" <seaint(--nospam--at)seaint.org>

Anyone:
Is there anything in the IBC or NDS or anywhere that says nails in withdrawal shall not be used for wind uplift?

Thanks.
Scott Haan.