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RE: Sign Structures

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Gary,
I have nothing else to what I have already posted.  There are a lot of signs on the Las Vegas strip that are amazing in their design challenge.  CPP has done a lot of modeling of unusual structures in their wind tunnel including signs.  They use a spring base support that can mimic the response of flexible structures.  That way they can evaluate the dynamic effects. 
 
We generally assume that wind and seismic are not dynamic effects, but that is not always true.  I get concerned any time I have a flexible structure that may be prone to wind dynamics and dynamic exacerbating conditions like notch effect. 

Regards,
Harold Sprague

> Date: Mon, 3 Mar 2008 07:51:45 -0500
> From: ghodgson(--nospam--at)bellnet.ca
> To: seaint(--nospam--at)seaint.org
> Subject: Re: Sign Structures
>
> Harold,
> I am going there in May (under protest) so I will go see this sign.
> Anything else you can tell me about it?
> Gary
>
> Harold Sprague wrote:
> > The sign in question does not warrent a dynamic analysis, but there
> > are signs along the strip in Las Vegas that sometimes are evaluated in
> > wind tunnels with modifications at the base to determine a dynamic
> > response.
> >
> > The Hilton sign in Las Vegas is 279' tall with a terrible plan and
> > elevation aspect ratio. The sign it replaced blew down in a wind storm.
> >
> >
> > Regards,
> > Harold Sprague
> >
> >
> > ------------------------------------------------------------------------
> > Date: Fri, 29 Feb 2008 09:15:41 -0800
> > From: d.topete73(--nospam--at)gmail.com
> > To: seaint(--nospam--at)seaint.org
> > Subject: Re: Sign Structures
> >
> > A "dynamic" analysis for a billboard.... Tomfoolery at its highest...
> >
> > On Fri, Feb 29, 2008 at 5:00 AM, Gary L. Hodgson and Assoc.
> > <ghodgson(--nospam--at)bellnet.ca <mailto:ghodgson(--nospam--at)bellnet.ca>> wrote:
> >
> > Thanks, Harold
> > I will be doing that. There is no guidance in our codes on
> > signs or
> > other non-building structures. Your codes go further than
> > ours, as ours
> > are only written in regard to buildings. If I want to design
> > a crane
> > runway, storage bin, or sign _for seismic loads_, I have to
> > refer to
> > American publications. The problem is that our codes don't use
> > the same
> > terms or geographical data.
> > In going up against this municipality, I have to be on firm
> > footing,
> > because my customer has a history of bad relations with
> > them--he has won
> > two law suits against the city and their three page letter (of
> > structural questions only) came two days after the latest
> > judgement was
> > published in the newspaper. This city has the first or second
> > highest
> > average income in Canada and they don't like billboard signs,
> > even if
> > though there a lot of them existing in the city. One of the
> > questions
> > was "did I do a dynamic analysis of the structure" (for a
> > 20'x10' sign
> > with a top at 25' above grade).
> > Gary
> > How many cases of beer do I owe you now?
> >
> > Harold Sprague wrote:
> > > Gary,
> > > The projected area in the plane of the sign is relatively small.
> > > Seismic may govern. You could categorize signs as nonbuilding
> > > structures. The loading is a function of the force
> > resisting system
> > > which establishes the response coefficient and the mass.
> > >
> > > Regards,
> > > Harold Sprague
> > >
> > > > Date: Thu, 28 Feb 2008 17:04:42 -0500
> > > > From: ghodgson(--nospam--at)bellnet.ca <mailto:ghodgson(--nospam--at)bellnet.ca>
> > > > To: seaint(--nospam--at)seaint.org <mailto:seaint(--nospam--at)seaint.org>
> > > > Subject: Sign Structures
> > > >
> > > > List,
> > > > I design sign structures for 2 clients-these are all
> > free-standing
> > > signs
> > > > on one or two posts. In our area, generally wind governs. A
> > > > municipality has questioned whether I designed a
> > particular sign for
> > > > seismic loading. Nothing in our codes addresses the issue
> > of signs
> > > > subject to seismic loading unless they are part of a
> > building, in which
> > > > case they are considered a fixture just like a mechanical
> > piece of
> > > > equipment. Our codes only require that signs over a
> > certain height or
> > > > area have to be designed by a professional engineer. So, I
> > guess my
> > > > question is what seismic loading do you design signs for?
> > Thanks in
> > > > advance.
> > > > Gary
> > >
> >
> >
> > ------------------------------------------------------------------------
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