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Re: Drift Limits for Wind

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To elaborate on Paul's response, I would agree that "yes", you can design
to "to meet L/240 for wind and the Delta_M for seismic".   You can design
to what ever wind drift limit you want (at least as far as the code is
concerned as I don't believe that there is any drift limits specified in
the code for wind).  Now, will you be "OK"?  Dunno.  Depends on what the
over all system (i.e. structural and non-structural items) can handle
before problems occur.  As another poster suggested, to much drift could
cause problems in your stucco finish (i.e. cracking, deteriorating, etc).

But, the point is that the only CODE require drift limit is for seismic
(that I am aware of).  Of course, "standard of care" might dictate some
wind drift limits, but "standard of care" can be harder to interpret than
code requirements.  ;-)

Scott
Adrian, MI


On Wed, 21 Sep 2005, Paul Feather wrote:

> Yes, unless the finishes require something more stringent than l/240.
>
>
> Paul Feather PE, SE
> www.SE-Solutions.net
> pfeather(--nospam--at)SE-Solutions.net
>   ----- Original Message -----
>   From: Gerard Madden, SE
>   To: seaint(--nospam--at)seaint.org
>   Sent: Wednesday, September 21, 2005 4:13 PM
>   Subject: Drift Limits for Wind
>
>
>   I must be getting old cause I can't seem to find this, so I ask all of you to refresh my memory..
>
>
>
>   I have a simple storefront renovation project and I am using cantilevered steel columns to resist the lateral wind load. The wind force governs over seismic by a factor of 2.
>
>
>
>   In UBC/CBC the Delta_M drift limit is 0.7*R*Delta_S .. Now that I know for sure is for seismic and is straight forward.
>
>
>
>   Since I have twice the load governed by wind, do I still need to meet this requirement?
>
>
>
>   I know technically there is no drift limit for 1 story steel construction and this is basically a false tower/covered entrance outside of an existing building but I'd still like to meet the drift limit since there are several illuminated signage type things and stucco finish that I'd rather not have bust all up under huge deflections.
>
>
>
>   Can I design it to meet L/240 for wind and the Delta_M for seismic and be okay?
>
>
>
>   TIA,
>
>
>
>   -gm
>

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