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Re[2]: Steel Building Bracing

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     There is an exception in the 1994 UBC in zones 3 & 4 for bracing of 
     one or two story buildings.  However, you must design the bracing for 
     3Rw/8.  (Section 2211.8.5 ) This is probably the section that the 
     "pre-engineered" buildings use.  I still see rod X-bracing in metal 
     buildings.
     
     Ed Haninger
     Fluor Daniel


______________________________ Reply Separator 
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Subject: RE: Steel Building Bracing
Author:  dhorning@CH2M.com_at_-FDInternet at FDINET
Date:    10/29/97 11:40 AM


Tom, where are you seeing a TENSION-ONLY provision in the UBC?  For 
Zones 3/4, the 1994 and 1997 UBC have stringent limits on slenderness 
ratios of braces and require compression braces to carry 70% of story 
shear.  This has eliminated use of rod x-bracing and virtually forced 
use of tubes.  If you have found a way around these provisions, I'm all 
ears (figuratively).
     
> ----------
> From:      Thomas Chiu[SMTP:Tomchiu(--nospam--at)worldnet.att.net] 
> Sent:      Tuesday, October 28, 1997 9:46 PM
> To:      seaoc(--nospam--at)seaoc.org
> Subject:      Re: Steel Building Bracing 
>
> Chris Towne wrote:
> >
> > What factor of safety is prudent on design of steel cable for 
> tension
> > x-framing?
> >
> > Chris Towne, E.I.T.
> >
> >
>
> Don't forget the 3 Rw/8 X the UBC seismic force in your design, I 
> don't
> have the UBC Code section handy but it should be under TENSION-ONLY 
> braced frame section. I had reviewed some engineer's design that did 
> not
> check for 3 Rw/8 x UBC forces and he ended up revising his details 
> that
> had gone for bid and cost the owner an arm and leg for the revision. 
> The reason being that they were using some old computer program that 
> never got updated for that section of the Code --- another unproper 
> use
> of computer program.
>
>
>