Existing Beam: Repair or O.K.?

Dear Mr. Allen: Of your three options below, I think the third option might be the way to go which to repair the damaged beam. However, we may need to find out first what caused this crack in the beam? Without knowing the cause of damage, the repaired beam can also be cracked for the same reason the original beam cracked. Option one "to do nothing" does not seem to me an option at all. Pretty much you have two options either repair the damaged beam and if that cannot be done in a reliable and economical way, then the beam has to be replaced.
Hope my 2-cents is helpful.
A. Astaneh-Asl, Ph.D., P.E.
Professor and Consultant on
Structural Engineering, Earthquake Engineering and Protection of
Buildings and Bridges against Blast and Impact
==========

From: "Bill Allen" <T.W.Allen@cox.net>
To: "Seaint" <seaint@seaint.org>
Subject: Existing Beam: Repair or O.K.?

I'm working on a small commercial remodel in Southern California. The =
part
of the work for which I'm responsible is nearly complete. However, when =
the
inspector came out to finalize the framing, he noticed problems in an
existing beam which is not part of my original scope of work. The =
building
is three stories and is rectangular. There is a beam line running down =
the
middle of the long direction. For my work, I had to remove and replace =
the
existing beam where the office is being remodeled. Beyond my work, the
existing beam is unmodified. What caught the inspector's eye are small =
holes
drilled in the beam used to pass electrical conduit. I haven't run the
numbers yet, but I believe these holes are O.K. What is troubling is =
that,
on one span, there is a long crack down the wide face of the beam for =
most
of the length. Worse yet, it appears that the beam above the crack has
rotated slightly. Below is a sketch prepared by my original CAD program.
I've exaggerated the rotation, but it is obvious. The beam is huge. It's
18-3/4"x701/4". It spans about 12-1/2 feet and supports two floors and a
roof. I'm concerned about two things; the ability of the beam to =
transfer
VQ/I stresses through the cracked region and the ability of the beam to
remain stable if the crack propagates. Maybe there are other things I =
should
worry about. There are three methods of addressing this problem that I =
can
think about off the top of my head and they are:

1. Do nothing; the beam is still structurally viable.

2. Add Simpson LTP4s at 12" o.c. or so which would stitch the crack =
in
the hopes that it will keep the crack from enlarging/propagating and =
will
hopefully transfer the VQ/I stresses by an unknown load transfer path.

3. Don't mess around with it and repair the beam by sandwiching two
PSLs, one on each side and designed to take 100% of the load. I would =
have
the contractor jack the beam as far as he can (there are bearing walls
above) before he bolted these beams to the existing beam. If I could get
100% of the load off the existing beam, it would then act to only =
transfer
the load to the PSLs.

What would you do and why?

TIA,

T. William (Bill) Allen, S.E.

ALLEN DESIGNS <http://www.AllenDesigns.com>=20

Consulting Structural Engineers
V (949) 248-8588 . F(949) 209-2509

=====================================

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