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RE: PEMB / Masonry expansion joints

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Thanks again, Harold,

I've already referenced DG #3 and other documents. 
Another useful publication I found since I last asked
(and you provided) for reference ideas is NCMA's
"Concrete masonry walls for metal buildings," a very
good publication with all the right information about
detailing the interface between the masonry and the
steel.  Putting all of this information together has
been quite enlightening, to say the least.

Jim

--- Harold Sprague <spraguehope(--nospam--at)hotmail.com> wrote:
> Jim,
> There are several considerations that I would
> suggest for consideration.  It 
> is important to note that this is a servicability
> issue, and not a life 
> safety issue.  Therfor the building code is not much
> help.
> 
> Lateral Drift:
> The standard for Butler Manufacturing for a masonry
> clad building is h/100.  
> I would suggest that you obtain the AISC Design
> Guide #3 "Serviceability 
> Design Considerations for Low-Rise Buildings". 
> Reference p 17.  I prefer to 
> limit the drift of the frame to h/200.  With proper
> detailing one can design 
> to h/100.  It really does not cost that much to
> require an increase in frame 
> stiffness when you look at the cost per square foot
> of the building.  Keep 
> in mind that this drift limit is for a 10 year wind
> not a 50 year wind.
> 
> Horizontal deflection:
> There is a lot of controversy on this issue, and the
> opiinions vary 
> depending on who's is citing the research.  The
> light guage people claim 
> that you can go to L/360.  But the same research
> (the Clemson Study) cited 
> by others would indicate L/720.  I have a bit of
> heart burn with the 
> research itself because of the types of mortar
> either used or not properly 
> cited.  N mortar is much better for crack healing
> than S mortar.  But that 
> is another issue.  The Canadian Mortgage and Housing
> Corporation (CMHC) did 
> an independent evaluation and suggests L/720.  But
> again, this is a 
> serviceability issue, and this would suggest a 10
> year wind.  My preference 
> is to use L/600 with a 50 year wind.  This is about
> the same as a L/720 with 
> a 10 year wind.  The L/600 is consistant with the
> Brick Institute of America 
> (BIA) recommendation.
> 
> Vertical deflection:
> Obviously this one is L/600 as mandated by most
> building codes. You can go 
> more with proper detailing, but why fight it?
> 
> There have been several good articles in The
> Magazine of Masonry 
> Construction on this issue.
> 
> PS Use G-90 galvanized studs.
> 
> Regards,
> Harold Sprague
> 
> 
> 
> 
> >From: Jim Wilson <wilsonengineers(--nospam--at)yahoo.com>
> >Reply-To: <seaint(--nospam--at)seaint.org>
> >To: seaint(--nospam--at)seaint.org
> >Subject: PEMB / Masonry expansion joints
> >Date: Thu, 19 May 2005 06:42:13 -0700 (PDT)
> >
> >If a metal building is designed to H/100 lateral
> >displacement, is it appropriate to size the
> vertical
> >expansion joints in the masonry facade at the
> >building's corners for an equal amount of movement?
> >
> >For example, 20ft tall building, masonry walls to
> 12ft
> >tall.  Lateral displacement = 2.4" at roof level,
> >1.44" at top of masonry.  Expansion joints in
> masonry
> >should provide for 1.5"(1.44") lateral movement.
> >
> >This seems obvious, but is there anything else to
> it
> >that I am missing?
> >
> >TIA,
> >Jim Wilson
> >Stroudsburg, PA
> 
>
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