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Re: questions!

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Actually, in the summertime it's "shake and bake".......

jim
----- Original Message -----
From: "Bill Polhemus" <bpolhem(--nospam--at)swbell.net>
To: <seaint(--nospam--at)seaint.org>
Sent: Thursday, September 14, 2000 4:28 PM
Subject: Re: questions!


> One problem with the ASCE 7 is that the research behind it has almost
entirely
> been funded by the Metal Buildings industry, and thus reflects a definite
slant
> in their direction as far as the recommended criteria. Why is it that
other
> "building industry" interests have not made themselves part of ASCE 7
> development?
>
> Because "good enough" is typically "good enough" for most engineers
(witness the
> hubbub that begins when I utter those four little letters "LRFD"). Most
> engineers simply want an equivalent pressure, and let it go at that
(witness the
> still simple-minded procedure for wind load computations in UBC 94).
>
> But the metal buildings folks try to engineer down to the gnat's arse.
They want
> every ounce of steel out of their designs they can get, and so they want
to know
> the difference between the equivalent pressures at "discontinuities" like
> corners and eaves, and that at the center of the structure.
>
> Look at the "examples" shown in your ASCE 7, and also the companion "Guide
to
> Use of the Wind Load Provisions" authored by Kishor Mehta. It's ALL metal
> buildings. They're not even very clear about how to handle a flat roof
with a
> parapet all around (Does the parapet provide some shielding for uplift on
the
> roof? Do you apply a "windward" load on one side and a "leeward" on the
other
> side of the same parapet? It isn't at all clear!)
>
> They weenie out of it all by recommending you do a "wind load test" for
> structures that don't readily lend themselves to the ASCE 7
recommendations--all
> very well for BL wind tunnel facilities like that at Texas Tech, but
highly
> improbable for use by designers of most low- and mid-rise buildings that
> represent the preponderance of such facilities for commercial use.
>
> Much as I love the advances in the provisions of ASCE 7 over the years
since it
> was established, I am wholly unsatisfied that only one industry, metal
> buildings, has chosen to get involved in that development.
>
> Thanks. Getting off soap-box now, and turning it back over to you "shake,
rattle
> and roll" guys in Seismic Zone 4.
>
> Keith Fix wrote:
> >
> > I want to know whether large numbers of re-entrant corners in relatively
small
> > buildings (1-4 stories, 250 ft maximum width) are correctly modeled by
building
> > code prescribed wind loads.  Thesis: "ASCE 7-98 Wind Forces are
(in)appropriate
> > for the design of mid-sized buildings with numerous re-entrant corners".
>
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