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RE: BILLBOARD SIGN DEFLECTION CRITERIA

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Steve,

1.  Good luck in finding deflection criteria for billboards per se.
AISC developed some general criteria for wind drift limits for low-rise
buildings in AISC Design Guide 3.  I don't think AASHTO has anything on
billboards.  The perceptibility criteria is based on human occupancy.
That should not be a concern for a billboard.  Your deflection criteria
should fall out of your gust factor calculations per the ASCE 7-95
commentary 6.6.  You will probably be in Category III.

2.  Look in the yellow pages under Advertising - Outdoor.  There are
several.  You can also look at the names at the bottom of billboards.
They list the people who own the signs.  These people can direct you to
the various billboard structural engineers.

Regards,
Harold Sprague
Black & Veatch
 ----------
From: uthoff(--nospam--at)S6.hninc.com
To: seaoc(--nospam--at)seaoc.org
Subject: BILLBOARD SIGN DEFLECTION CRITERIA
Date: Thursday, October 09, 1997 10:12AM


I have a billboard with two flagpole type column supports.  The sign has
about 450 square feet of surface about 20 feet up in the air.

1.  Does anyone have any recommended deflection criteria for billboards?
 The sign I'm looking at will have people around it most of the time.  I
think AASHTO has a code on it, but I can't find it right now.  I know
you do
not want the vibration to be perceptible in moderate winds (say 30 mph),
yet
probably will accept perceptable deflection for maximum wind (70 + mph).

2.  Does anyone have names & phone numbers & contact person for
billboard
sign manufacturers.  I can find flagpoles in Sweet's (10350), but not
billboards.  I've heard that the flagpole supports are tapered partly
because it damps out any potential resonance (variable moment of inertia
=
variable natural period) under wind loading.  I wanted to call and learn
more.


Thanks

Steve Uthoff, S.E.