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RE: steel brace

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Greg,

This is an eccentric braced frame with a long link beam.  Re: UBC 2211.4.
The length of the liink beam has a dramatic effect on the lateral drift.
The longer the link the greater the lateral drift.

Regards,
Harold O. Sprague

> On Tue, 23 Jul 2002, Greg Meyer 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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