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Re: Roof Framing, Joist Spacing...Input please

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I believe that the table that you are looking at ("Recommended Maximum
Spans for Construction and Maintenance Loads Standard for 1 1/2" and 3"
Roof Deck") is for loads during construction to prevent damage.  I
certainly could be wrong.  That SDI table is repeated on page 10 of the
Vulcraft catalog.

The SDI spans listed on pages 3-7 for the specific Vulcraft tables (table
at bottom of each page in column #3) is for "permanent" loading...at least
I think.

That might explain some differences.  I had forgotten about the table on
page 10.

Scott Maxwell, PE, SE


On Fri, 21 Jul 2000, c2 wrote:

> Scott,
> 
>   <<  I will say again that I am not sure where you are getting the 5'-0"
> limit.>>
> 
> I refer to SDI Specifications and Commentary ie: "Recommended Maximum Spans
> for Construction and Maintenance Loads Standard for 1 1/2" and 3 Inch Roof
> Deck."
> 
> In these tables, note that NR22 with a span condition of "2 or more" is SDI
> limited to a max span of 4'-9".  In the corresponding load tables of
> Vulcraft's same catalog under "VERTICAL LOADS FOR TYPE 1.5F", again, lists
> "Max. SDI Const. Span" as 4'-9", yet the Vulcraft load tables allow a 41 PSF
> load for a single span on this same deck on a span condition of 6'-0".  I
> consider a 41 PSF a reasonable load combination in this area.
> 
> To futher add to the confusion, Vulcraft lists F22 deck on a three span
> condition as SDI maxed at 5'-10", (conflicting with SDI published tables of
> 4'-9" for "2 or more spans")  This same deck in Vulcraft's catalog on a
> three span condition is listed as 41 PSF at a 7'-0" span condition.  Again,
> a reasonable load combination in this area.
> 
> I am looking at Vulcraft's 1996 catalog on p.4 with the SDI "Max Spans"
> listed on p. 10.  It is not untill one reaches a deck configuration of NR18
> in the SDI tables that the allowable single span exceeds 5'-0".
> 
> I certainly don't call these restrictive SDI load limits as "promoting" the
> use of steel decks.  About the only thing I see it "promoting" is confusion
> and the likelihood of a lawsuit.
> 
> 
> Jimmy  C.......(hisself)
> 
> 
> 
> 
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