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RE: steel brace

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Greg,
I can think of two issues for this type of bracing:
1- The unbalanced load of the single brace needs to be
transferred through the beam. So you will end up with a
heavy beam section.
2- There are limits on the percentage of the seismic load
that can be resisted by tension-only/compression-only
braces. So you may want to make sure that there are other
braces in the system to act in the opposite direction.
Hope it helps,
Frank

--- Greg Meyer <gmeyer(--nospam--at)scahouston.com> wrote:
> Scott, Thanks for your input.  It would just be a single
> brace member.
> Essentially what I have is 1/2 of a inverted "V" chevron
> brace.
> I guess that it would fit the criteria of  UBC 2213.8.4.3
> Nonconcentric
> bracing.
> 
> Greg
> 
> -----Original Message-----
> From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
> Sent: Tuesday, July 23, 2002 2:17 PM
> To: 'seaint'
> Subject: Re: steel brace
> 
> 
> Greg,
> 
> Based upon your limited description, I would say yes you
> can use this type
> of brace, but a little more information would be helpful.
> 
> Is there another brace that meets this one at the middle
> of the beam
> coming from the beam to column connection at the other
> side of the beam?
> 
> If so, does the working point of the braces (essentially
> the centerlines)
> meet roughly at the centerline of the beam?
> 
> If the answer to the first question is "no", then it
> sound like an
> eccentric brace system.
> 
> If the answer to the first and second question is "yes",
> then is sounds
> like a concentric brace system.
> 
> If the answer to the first question is "yes" and the
> second is "no", then
> it sounds like another configuration for an eccentric
> brace system.
> 
> FYI, an eccentric brace system relies on getting its
> brace force into a
> beam or column by both bending and resolution of the
> axial loads into
> component forces (like a truss member), in general terms.
>  An eccentric
> brace system will have a "link" beam segment that is
> designed to create
> the ductility in the system (note an eccentric brace
> system is typically
> more ductile than a concentric brace system).  A
> concentric brace system,
> OTOH, will not rely on any bending to transfer force from
> the brace to
> beam or column.
> 
> HTH,
> 
> Scott
> Ypsilanti, MI
> 
> On Tue, 23 Jul 2002, Greg Meyer wrote:
> 
> > 	I would like to use a brace that goes from a beam to
> column connection at
> > one level to the middle of a beam at the next level.
> > The brace would be part of the lateral resisting system
> for a building
> > located in a seismic zone 3  (1997 UBC).
> > It doesn't seem to meet any of the definitions for
> braces in the UBC.
> >
> > Can I use this type of brace?
> >
> > If I can, how would this brace be classified?
> (Eccentric, Concentric, etc)
> >
> >
> > Thanks in advance,
> >
> > Greg Meyer
> >
> >
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=====
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