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Re: Concrete Nails

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Daryl,

Could you clarify something...the 2x6s...are they oriented vertically so
that one end is sitting on the floor/footing (almost like a wood pilaster
that is just nailed to the wall) or oriented horizontally with all the
load being supported by the concrete nails?

I would be leary about the latter.  While I don't have concrete evidence
(no pun intended), I would think that concrete nails don't have too much
tension capacity.  Such a situation would have been better achieve with
either epoxied bolts, thru bolts, or expansion/sleve anchors.

If the former, then I would not see to much of a problem with it.

HTH,

Scott
Ypsilanti, MI


On Sat, 3 May 2003, Daryl Richardson wrote:

> Fellow engineers,
>
>         A colleague of mine, a registered P.Eng., is facing a discipline
> committee hearing regarding the suitability of one of his structural
> designs.  He has asked me to sit in as an expert witness on his behalf
> and I have agreed to do so.  One of the key issues will be the
> suitability of the use of concrete nails in securing a double 2x6 "post"
> to a concrete foundation wall.  To help me prepare for this role I would
> appreciate any comments you are prepared to send.
>
>         The situation details are the following.
>
>         The hearing date is May 13, but some documents must be filed by
> May 6 (not yours, of course).
>
>         The project is standard residential wood frame construction.
> The house is a single family "split level" located in south/central
> Alberta.  Seismic is virtually zero; wind is fairly high; but neither of
> these are applicable to the case.  Usually a structural engineer is not
> involved with a single family residence in Alberta unless there is some
> special circumstance such as an unusual beam arrangement, a retaining
> wall, or some problem such as the one I am describing develops.
>
>         The floor system is 2x10 floor joists supported on laminated
> wood beams (possibly MicroLam or ParaLam both of which are made op of
> approximately 1/8" laminations with the glue plane vertical and
> totalling 3.5" in width) which are, in turn, supported on columns.
> Normally, there is a pocket cast in the foundation wall to support the
> end beam beam reaction; but on this project the pocket was omitted,
> hence the problem.
>
>         The foundation wall is 8" thick; the strength and age of the
> concrete are unknown.  Normally, concrete strength would be about 2,500
> p.s.i. and it could be normal or sulphate resistant.  One may speculate
> that the concrete age might be from 5 to 15 days.  Below the wall is a
> footing 6" thick and 16" wide.  There is no requirement for reinforcing
> steel in residential concrete basements although some builders place ten
> millimetre or #4 bars horizontally at 15" centres.
>
>         Since the beam pockets were omitted my colleague got involved.
> His solution was to place a 2x6 "on the flat", against the wall and nail
> it to the wall using ten 5" long by 3/16" diameter concrete nails.  He
> then took a second 2x6 and nailed this directly to the first using "an
> appropriate number of ordinary wire nails".  This provides a 3" seat for
> the laminated beam.  The double 2x6 are approximately 5' long or less
> and are also in contact with the wall's strip footing.  The slab on
> grade basement floor is placed directly on top of the wall footing
> encasing the double 2x6 post.  Unless I have been misinformed there has
> been no indication of a failure taking place.
>
>         Please comment on a) the suitability of using concrete nails in
> this way, b) the capacity of such nails, or c) anything else related to
> this situation you want to.  All replies will be appreciated.
>
>         Thank you.
>
> Regards,
>
> H. Daryl Richardson
>
>
>
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