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RE: heavy timber frame

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Bruce,

 

Ell-shaped plates installed into kerfs in the centers of the beams and columns would engage the wood each side of the plate in double shear; this seems like a reasonable way to stiffen the frame – the length of the plates and kerfs would be based on the moment and the perpendicular-to-grain capacity of the bolted connections.  The holes would need to be drilled with templates and drill press in order to avoid the need for oversized holes.

 

Nels Roselund, SE

South San Gabriel, CA

njineer(--nospam--at)att.net


From: Bruce Holcomb [mailto:bholcomb(--nospam--at)brpae.com]
Sent: Thursday, September 15, 2005 3:05 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: heavy timber frame

 

Drew,

We did discuss that just a little while ago.  That may be a good option as well, although I wonder about the potential movement in the bolted joint due to oversizing the hole.  I will probably need to look at this option a little but for now, I’ve been asked to not make any changes… the “higher-ups” are discussing…

 

Thanks.

 

 

BDH

 

-----Original Message-----
From: Drew Morris [mailto:dmorris(--nospam--at)bbfm.com]
Sent: Thursday, September 15, 2005 4:47 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: heavy timber frame

 

Could you add "L" shaped steel plates in the upper corners centered in the beams and columns with just bolts exposed?  I'm not sure if this would calculate out with the bolts bearing perpendicular to grain, but it would stiffen the joints.  Or hide the plates away from view?

Bruce Holcomb wrote:

I have been asked to review a heavy timber frame which will be located inside of a retail store and will serve as a canopy over a snack bar.  The drawings I received showed 8x8 posts, 8x12 beams and 4x10 purlins… all of Cedar.  I see nothing providing lateral stability for the structure.  Even though it is inside another building, I want to make sure it doesn’t fall over when the first tired customer leans against a post, so I added 6x6 knee braces, lag screwed into the beams and columns.  The knee braces extend 2’-0” from the inside of the beam / column joint each way.  The client had a fit… they don’t want any additional bracing.

 

The beams and columns are typically connected with ¼” steel kerf plates.  Has anyone built this kind of structure without additional bracing?  Basically, the ¼” kerf plates create a moment joint?  The timber framer has said he wanted to change the kerf plates to mortise and tenon joints… will that create some lateral stability?

 

I’m not too concerned about seismic… it’s in the Midwest, but I may have to produce calcs to provide to the city reviewer.  I want to make sure I can “prove” the structure is laterally stable.

 

 

Bruce D. Holcomb