What Scott says goes along with our Canadian codes.
Gary
Dennis Wish wrote:
>
> This makes more sense and I would have to yield to you on this because
> of the lack of snow loads in the majority of Southern California.
> According to the 97 UBC we applied what the building official provided
> as the snow load for the elevation and region regardless of slope and
> had an increase on the eaves. The wording of this section is somewhat
> ambiguous for those of us not familiar with snow loads according to
> the IBC provisions.
>
> Unless anyone else has another interpretation, I will accept Scotts
> explanation of snow loading and add this to Multi-lat(mt). Thanks Scott.
>
> Dennis
>
> *From:* Scott Maxwell [mailto:smaxwell@umich.edu]
> *Sent:* Sunday, July 20, 2008 7:06 AM
> *To:* seaint@seaint.org
> *Subject:* RE: ASCE 7-05 Section 12.14.8.1 (#4) clarification needed
>
> I interpret this as if the flat roof snow load (Psubf) exceeds 30 psf,
> then you take 20% of the FLAT roof snow load (Psubf) and add that to
> the seismic mass. You do NOT take 20% of the SLOPED roof snow load
> (Psubs)...that is the "regardless of actual roof slope" part. And you
> do NOT take 20% of the portion that exceeds 30 psf.
>
> Thus, if you have a 40 psf flat roof snow load and a 12:12 roof pitch
> on a non-slippery roof such that the sloped roof snow load is 24 psf,
> then you would add 8 psf (20% of 40 psf) to the seismic mass...NOT 4.8
> psf (20% of 24 psf).
>
> Regards,
>
> Scott
>
> Adrian, MI
>
> -----Original Message-----
> *From:* Dennis Wish [mailto:dennis.wish@verizon.net]
> *Sent:* Saturday, July 19, 2008 9:56 PM
> *To:* seaint@seaint.org
> *Subject:* ASCE 7-05 Section 12.14.8.1 (#4) clarification needed
>
> I need an interpretation to note number 4 of ASCE 7-05 Section
> 12.14.8.1 which states:
>
> "Where the flat roof snow load, Pf, exceeds 30 psf (1.44 kN/m^2),
> 20 percent of the uniform design snow load, regardless of actual
> roof slope."
>
> This seems to conflict with itself. My first interpretation is
> that if the snow load for a flat roof (say ¼" in 1-foot) slope or
> a shed roof exceeds 30 psf then you would add 20% or 6 psf to the
> roof dead load. However, the last section of the statement reads
> "regardless of actual roof slope" in which case I would interpret
> the 20% of the Snow Load exceeding 30-psf to be added to any
> sloped roof.
>
> How do others interpret this statement. If the roof is flat should
> 20% of any Snow Load be considered whereas only 20% of the Snow
> load exceeding 30-psf be used if the roof is pitched?
>
> Dennis S. Wish, PE
>
> Dennis S. Wish, PE
>
> California Professional Engineer
>
> Structural Engineering Consultant
>
> La Quinta, CA 92253
>
> dennis.wish@verizon.net
>
> http://structuralist.wordpress.com
>
> http://www.structuralist.net
>
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