RE: Glu-Lam beam with Steel Channel calc

Erik,

There are a few issues with transferring the load, bolting, stiffness, etc from the glb  to the steel section, and it also appears that you are removing some of the high strength laminations from the bottom of the beam,

I would design the new steel section to handle ALL the load, but that's just me

Tarek Mokhtar, SE

Laguna Beach

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@gmail.com]
Sent: Thursday, August 02, 2007 10:59 AM
To: seaint@seaint.org
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%?

 

Thanks

 

Erik Gibbs

 

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Tarek Mokhtar, SE
TMM Structural Engineers, Inc
31645 S. Coast Hwy
Laguna Beach, CA., 92651
949-499-6254
949-499-2777 Fax