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Re: "Blown Away"

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1997 Uniform Building Code, Division III - Wind Design, Section 1615 -

"Every building or structure and every portion thereof shall be designed and
constructed to resist the wind effects determined in accordance with the
requirements of this division."

Seems clear and succinct.  Probably the other codes say something similar.

John P. Riley, PE, SE
Riley Engineering
20 Oakwood Drive, Blue Grass, Iowa 52726
Tel & Fax:  319-381-3949

> Recently, an architect client of mine and I were discussing a feature of a
> commercial building we were working on. He does lots of convenience
> food combination facilities. One client has a "doghouse" at the front
> of the store, a "penthouse" type structure that allows a sign-logo above
> entrance that extends about eight feet or so above the parapet line.
> The doghouse itself is CFS supporting metal cladding, which sits on the
> and joists of the main structure.
> The design drawings given me showed a CFS structure that was WAY
> to resist code-specified wind forces, and I proceeded to design it
> which made for a much "beefier" structure, particularly where the roof
> and overall connnections were concerned. When he saw this, he had a
> reaction. "Too much", he said.
> I pointed out to him that we were building in an area where the design
> speed is 120 mph (three-second gust). His response was "oh, that doesn't
> if they had a hurricane, the doghouse would just be blown off, and they
> build it back again".
> I had NEVER heard of this approach before! In essence, he's saying "just
> it to handle gravity loads and don't worry about wind, this is not an
> portion of the structure. If it gets scoured off, no big deal".
> Have any of you designed "components and cladding" type portions of a
> under this approach? The architect insists it is perfectly valid: "we do
it all
> the time". Of course, this guy is the "Wal-Mart" of architects in our
> and is used by developers here because he works cheaply, and doesn't get
> their way.
> I'm starting to rethink my relationship with him on this basis, but I'd
like to
> know if this is perhaps more commonplace than I realize, and if I'm
> "overreacting". I just can't imagine a building department anywhere
allowing a
> portion of a structure the possibility of being "blown away".
> Thanks