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Re: GLB Failure

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I am aware of many GLB failures such as you describe. The school district in
Anchorage, Alaska has experienced several failures and became so concerned
that they inspected all of the GLB's in all of the schools. I can provide
the name of an engineer involved with this problem if you desire. Contact me
via email.

I personally have been involved with only one case and it was catastrophic.
Luckily no injuries. The failure occurrs in the glue lines.

James Allen, P.E.
-----Original Message-----
From: Parkerres(--nospam--at)aol.com <Parkerres(--nospam--at)aol.com>
To: seaint(--nospam--at)seaint.org <seaint(--nospam--at)seaint.org>
Date: Friday, September 18, 1998 11:52 AM
Subject: GLB Failure


>To all:
>
>A question regarding possibile causes of the failure of a glulam beam:
>
>At the request of a client, the other day I looked at a glulam beam which
had
>failed in the roof of a one-story building.  (Fortunately, we did not
design
>this.)  The building is about 20 years old, and the beam appears to be
about
>5-1/8" x 24".  The beam is about 42' long supporting a panelized wood roof
>system.  There is nothing of note weight-wise on the roof.
>
>The beam has "broken" at about midspan and is now temporarily shored.  The
>finger joint in the lowest lamination has separated about 3", and there are
4
>or 5 other major cracks in the beam at the failure point.  The cracks are
>primarliy horizontal but are diagonal enough to be extending through the
>laminations not along the glue lines.  The beam has sagged about 6" due to
the
>failure and was probably hanging from the roof until it was shored.  The
beam
>is over a kitchen area.   Reportedly, someone heard a "pop" and noticed the
>ceiling was sagging.  The failure was noticed when the ceiling was opened
to
>inspect the beam.
>
>We are recommending that the beam be removed and replaced from above, which
>the owner is willing to do.
>
>However, I am curious as to possible failure causes.  There is no unusual
>equipment on the roof and the building engineer says they have no ponding
>problems.  Could the failure be related to heat or gases from the kitchen?
>Could it be a latent defect?
>
>Any thoughts and/or similar experiences would be appreciated.
>
>Thanks,
>
>Bruce Resnick, S.E.
>Parker Resnick Str. Eng.
>
>
>
>