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Re: Question on wood Roof Trusses

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While in most cases it would still not apply, but I thought it worth
mentioning.  If my memory serves me correctly, it the tributary area of a
"Component and Cladding" element exceeds 700 sq ft, the loads can be
determined by the "Main Wind Force..." procedure.  As mentioned, I doubt
most the cases you are considering "trigger" that limit.


On Tue, 16 Jan 2001, Bill Polhemus wrote:

> Can I venture a guess, and see if I'm right?
> The truss manufacturers are simply looking to save money, that's all.
> They have somehow justified to themselves that the joists are part of the
> "primary framing" (or "Main Wind Force Resisting System" to use the ASCE 7
> terminology) rather than an "element/component" (or "Components and Cladding"
> per ASCE).
> I, too, think they are wrong, and I would simply specify on the drawings or
> specs that the joists are to be so designed, and fix the problem once and for
> all.
> Monty Hart wrote:
> > 
> > While we are discussing roof trusses.  Can someone tell me why the truss
> > manufacturers use the "Primary frames and systems" Wind Pressure Coefficients (Cq
> > in the '97 UBC Table 16-H), instead of the "Elements and Components"
> > coefficients.