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Re: Glu-Lam beam with Steel Channel calc

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If you are removing lams, I'd basically ignore the GLB's contribution since the good wood on the lower fibers are gone.

Are you using an unbraced length = to the span for the channel? If you are bolting to the existing GLB or connecting to the diaphragm somehow, you can reduce that for LTB. What about a W8 or W10? Shore joists/rafters, remove (E) header, put in new PSL, Powerbeam, or Steel flush beam?


On 8/2/07, Jerry Coombs <JCoombs(--nospam--at)> wrote:
Exactly.  Those are "filler" layers, and are generally low-grade.  Reality is, you don't know what they  are. 
RE: loading, with the proper number of connectors, you can ensure that they will be loaded "simultaneously", but you still won't know what the wood contribution is.

>>> On 8/2/2007 at 1:30 PM, "Josh Comfort" <jcomfort(--nospam--at)> wrote:
When you say "taking off a few laminations" it sounds to me as if you are proposing cutting off the lower portion of the existing glulam beam, is that correct?  If so, you'll want to be sure to take into account the new grade of lumber that you have at the tension face of your beam when figuring F'b.
-----Original Message-----
From: erik gibbs [mailto: erik.gibbs(--nospam--at)]
Sent: Thursday, August 02, 2007 10:59 AM
To: seaint(--nospam--at)
Subject: Glu-Lam beam with Steel Channel calc

I previously posted a question about a plan check question for out of plane loading on a shearwall and to all that posted I thank you, it cleared up any questions that I had.
Now to my new question. I have an existing 5-1/8" x 15"  Glu Lam beam that spans 21'-6" in a garage of an existing residence. The owner wants to turn this into a flush beam, which means taking a few laminations off and sistering a new beam next to the GLB. I want to use a steel channel, C10x15.3, but this section, when checked in bending fails under the full load. Also the GLB fails under the full load when checked by itself. My question is how would you check/calc both beams in a rational method, instead of just saying that the GLB takes 50% of the load and the steel beam takes the other 50%?
Erik Gibbs