Thursday, November 19, 2009

Re: Can 2x6 T&G roof or floor consider to be a diaphragm?

Concrete Home Building Council? These numbers look too high. I've been
used to the Western Woods User Book values/methodology (Section 10.3)
which gives you about 50 plf for joists at 16" oc. With joists a 54"
you'd get 50plf x 16/45 = 15plf. Each set of nails develops a force
couple and the density of these gives you the shear capacity. These
joists are too far apart IMHO.

Jnapd@aol.com wrote:
> Ken
>
> Are the 2x6's perpendicular to framing or diagonal ?
>
> Roof
> perpendicular = 100plf
> diagonal = 250plf
>
> Floor
> perpendicular = 100plf
> perpendicular = 500plf
> w/ wood flooring
>
> diagonal = 250plf
> w/ wood flooring = 600plf
>
>
> I believe it is 2-16d's @ each support min.
> 2007 CHBC Table 8-8A
>
> Joe Venuti
> Johnson & Nielsen Associates
> Palm Springs, CA
>
> In a message dated 11/18/2009 3:43:03 A.M. Pacific Standard Time,
> mStuart@cmxengineering.com writes:
>
> It is very likely that the existing deck was horizontally spiked
> together such that the spikes plus the T&G resistance will enable
> the deck to act as a diaphragm.
>
>
>
> *D. Matthew Stuart, P.E., S.E., F.ASCE, SECB*
>
> *Senior Project Manager*
>
> *Structural Department*
>
> *Associate*
>
> *Engineers and Consultants - CMX
> <http://www.cmxengineering.com/index.htm>*
>
> 200 Route 9
>
> Manalapan, NJ 07726
>
> 732-577-9000 (Ext. 308)
>
> 908-309-8657 (Cell)
>
> 732-298-9441 (Fax)
>
> mstuart@CMXEngineering.com
>
>
>
> ------------------------------------------------------------------------
>
> *From:* ken ng [mailto:zy7up@yahoo.com]
> *Sent:* Wednesday, November 18, 2009 1:07 AM
> *To:* seaint@seaint.org
> *Subject:* Can 2x6 T&G roof or floor consider to be a diaphragm?
>
>
>
> 1. 1. I have a 1945 building and it has 2x6 T&G (2" Vert. and 6"
> Horiz) roof and the floor is nailed directly to beams at 54"o.c.
> Can I consider these are flexural diaphragms with 54" existing
> nail spacing?
>
>
>
> 2. 2. What about additional floor or roof joists that were added
> @ 18" o.c. with new nails at 18" o.c. Will this be considered to
> be a diaphragm?
>
>
>
> 3. 3. Or ½" plywood shall be added on top of existing 2x6 T&G?
>
>
>
> 4. 4. The drawing plan called out some live load for Storage in
> 1945. However the hand created drawing was not so clear to read.
> I could not read the numbers if it's 50#, 75#, 100#, or 125#.
> Does anyone know what was the 1945 UBC required for this year?
>
>
>
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>


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