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Re: Wood Fasteners [was Re: Re: 1/3 increase]

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Nels,

The Supplementary Requirements of ASTM Specification F 1667 (Standard Specification for Driven Fasteners: Nails, Spikes, and Staples) specifies nail bending yield strengths, as required by UBC and AF&PA/AWC NDS for engineered designs, such as shear walls and diaphragms. Section S1.5 of this supplement calls for identification of fasteners meeting these requirements as follows on packages or containers: "Engineered Construction Nails, ASTM F 1667."  Of course, the proper size and type of nail as specified by the engineer should be identified also.  Some engineers list the length, shank and head diameters for the specified nails in the design notes on construction drawings.  Others may just "bite the bullet" and base the design on the lower code values for box nails (or other types per F 1667), instead of common nails.

Hopefully the CUREe fastener lateral load testing project being conducted by Dr. Gerard Pardoen at UC-Irvine will put these questions to bed, once and for all.

John Rose
APA (Retired)

"Nels Roselund, SE" wrote:

George, I find nail sizes on the job are difficult to control.  A framer was using nails that were specified to be 16d commons.  I could tell by the head size of installed nails that they were not 16d commons -- they looked like 8d commons.  I challenged the framer about it.  He showed me the box they were in [a box of about 15# of nails] -- it was labeled 16d common.  I don't know what they really are, but they are the diameter of an 8d common nail [0.131"], and 3-1/4" long instead of 3-1/2".  The actual diameter and length were printed on the box under the label "16d Common".  The framer "knew" that he was using what was specified -- not because of the size notations, but because the box said "16d Common". I'm thinking of requiring that a board that displays a specimen of the actual nail of each specified size be submitted to the Engineer prior to beginning construction -- after my review and acceptance, the board would be set up on the site to be used to compare a nail with the acceptable standard for each structural nail size.  Has anyone tried this? Fasteners for wood construction are a big problem -- in addition to nails, wood screws and lag screws listed in the NDS seem to be impossible to find on the supplier's shelf, and, if apparently found, impossible to verify on the job.  I specify the Simpson SDS1/4 screws whenever practical -- at least you know what you are specifying, the ICBO ES report makes clear what the allowable values are for just about any application, and they can be identified after installation.  But at $0.75 + per screw they are pretty pricey. How are you guys and gals handling this wood fastener business? Nels Roselund
Structural Engineer
South San Gabriel, CA
njineer(--nospam--at)att.net