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1/2" A307 bolts or lag bolts

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Title: 1/2" A307 bolts or lag bolts

If you are looking for design values for these bolts in wood, they are in the NDS(r). The equation for lag screw withdrawal values is: W=1800 * G^(3/2) * D^(3/4) where G is specific gravity of the wood. Units are lbs. per inch of thread penetration in the main member. For a 1/2" lag with G=0.50 (DFL), W=378lbs./inch

The lateral design values are not as easily spelled out, but here's an example:

1/2" bolt with 1-1/2" main, 1-1/2" side, G=0.50 (DFL), both members loaded parallel to grain Z=480lbs.
1/2" lag screw with 1-1/2" side member, G=0.50 (DFL), both members loaded parallel to grain Z=390lbs.


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
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.

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.


From: Peggy Dall [mailto:pdall(--nospam--at)]
Sent: Wednesday, March 02, 2005 11:29 AM
To: seaint(--nospam--at)
Subject: 1/2" A307 bolts or lag bolts

Does anyone know where I can find some design information (shear and
pullout) on these bolts? Thanks in advance.