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RE: Cutting a Glulam Beam

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Everybody is telling you that you can't cut the glulam but they're not
giving you any suggestions.  I have been in almost an identical
situation.  I resolved this by planning on removing at least 4.5" the
glulam (maybe more).  The plan is to lag bolt a thin plate to the bottom
of the glulam.  You may need to remove an additional 3/4" -1" to hide
the plate and the bolt heads.  The procedure is to assume that the plate
will be designed to handle 100% of the tension required in the flexural
component.  If you are able to determine what the interior LAM strengths
are then you need only design for the difference between the required
tensile capacity and the capacity of the modified beam.  The next step
is to perform a shear flow calculation to determine the correct
attachment per linear foot of the lab bolts to the glulam.  This
calculation for materials with different properties is illustrated in
most "design of materials" books.  If not I'm sure somebody will be
happy to supply it from the list.  One thing to realize is that the
plate need only be as long as the portion of the beam were the actual
capacity is less than the required capacity.  As the moment decreases
the farther from the center (assuming simple span) the farther away the
lag bolts can be spaced.  The same principle will apply in regards to
the modified moment of inertia when checking the beam for deflection.  


To: seaint(--nospam--at)seaint.org
From: Shafat Qazi <seaint-ad(--nospam--at)seaint.org>
Subject: Cutting a Glulam Beam

One of my clients wishes to install a garage door to his two car garage.
The header beam is too low and needs to be reduced in depth by about 4.5
inches. One of the solutions proposed by the client's contractor is to
remove the bottom three laminations and add a new post + pad  about
mid-span. The current Glulam beam is 21 inches deep. It works as a 16.5
inch beam for the reduced span.

Question: Is there a problem if he cuts 4.5 inches from the bottom of
the
Glulam?

Shafat