National Structural Firm
Tim Rudolph
ken ng
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?
Stuart, Matthew
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
200 Route 9
Manalapan, NJ 07726
732-577-9000 (Ext. 308)
908-309-8657 (Cell)
732-298-9441 (Fax)
mst...@CMXEngineering.com
Jn...@aol.com
Johnson & Nielsen Associates
Palm Springs, CA
Chuck Utzman
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.
Jn...@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,
> mSt...@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)
>
> mst...@CMXEngineering.com
>
>
>
> ------------------------------------------------------------------------
>
> *From:* ken ng [mailto:zy...@yahoo.com]
> *Sent:* Wednesday, November 18, 2009 1:07 AM
> *To:* sea...@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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