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Re: Wood Dowels embedded in concrete

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Title: Re: Wood Dowels embedded in concrete

Jim/Scott,

Nels already recommended TR12, which is a good reference for this question if you don't have the 2001 NDS.

However, wrt the suggestion to ignore certain equations in the 2001 NDS, this is incorrect. We consolidated all the connection equations in the 2001 NDS (based on TR12) and now all equations must be checked for different dowel-types. There is no longer the option to ignore certain yield modes for certain fasteners and materials.

Note that all equations except 11.3-2 use Fem (concrete dowel bearing strength) in some fashion (note the k1, k2, k3 and Re equations), so these yield modes cannot be ignored.

There's a paper describing the changes to the 2001 NDS on our website:

http://www.awc.org/Publications/papers/NDS2001article.pdf

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.

*********************
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: Scott Maxwell <smaxwell(--nospam--at)engin.umich.edu>
To: seaint(--nospam--at)seaint.org
Subject: Re: Wood Dowels embedded in concrete

Jim:

Section 8.2.3 of the 1997 NDS might help some.  It seems to give some
guidance on how the Table 11E (and the similar if not identical table 8.2E
in the 1997 NDs) are determined.  According to section 8.2.3 of the 1997
NDS, you are to use the lesser of Equations 8.2-2, 8.2-3, 8.2-4, 8.2-5 and
8.2-6 (which equate to 11.3-2 through 11.3-6 in the 2001 NDS).  You use
the dowel bearing strength of the concrete or masonry for Fem and it
appears the embeddment depth of the masonry for tm or lm (note that since
you don't use Equation 8.2-1/11.3-1, then the only Equation with tm/lm is
8.2-4/11.4/-4).

HTH,

Scott
Adrian, MI


On Thu, 11 Nov 2004, Jim Wilson wrote:

> NDS Table 11E is for single shear sawn lumber bolted to concrete with an embedment of 6" or greater.  For a case with less than 6" embedment, is there some sort of an adjustment factor to determine the capacity?  For a paltry couple hundred pounds of loading, is a 6" embedment any different than a 3" or 4" embedment?

>
> Or is it perhaps acceptable to use either Table 11J for lag screws or Table 11A for bolts, hopefully as a conservative backup?  Table 11A would be a much better value, but then what would be the thickness for the main member?  It might be reasonable to use a large thickness for the main member to better model the concrete, but that might be a real stretch.

>
> Jim Wilson, PE
> Stroudsburg, PA