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RE: Unreinforced Masonry Building

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We had a similar problem with several warehouses n Florida.  We were
renovation small portions of the buildings and noticed that there was
insufficient reinforcing (i.e., none) in the cmu walls.  Lucky for us,
the building was not designed by us.  We "fixed" this by saw cutting the
face shell out of a full height cell at whatever spacing we need, added
rebar, forming the cut side of the block (by Tapcon screwing plywood to
the cmu) and grouting the reinforced cells.  It was not pretty, or
inexpensive, but it worked.  You may want to try and use larger bars at
a slightly larger o.c. (maybe 6'-0" o.c.) spacing to cut down on the
quantity of repairs.


Charles F. Espenlaub, III, P.E.
Martin-Espenlaub Engineering



-----Original Message-----
From: David Hall [mailto:Dahl(--nospam--at)deainc.com]
Sent: Friday, February 11, 2000 12:42 PM
To: RickLennen(--nospam--at)AOL.COM; seaint(--nospam--at)seaint.org
Subject: Unreinforced Masonry Building


A few weeks back I sent out a request asking if anyone knew how to
conduct non-destructive testing to determine if reinforcing and grout
was placed in the voids of an existing masonry building.  I appreciate
the responses that I received from many of you.

Well guess what.  There was only grout and reinforcing in the horizontal
bond beams which were placed at 4 foot centers horizontal, in the
lintels, and vertically at each side of the expansion joints and
openings.

Now heres another one for you, there are 15 of these building designed
by our office and from what I recently heard 12 more that were designed
by another.  

These buildings are telecommunication building in Texas which is in
seismic zone 0 with a 80 mph wind speed.  I haven't checked yet but I
believe that #4's at 4 feet on center will work vertically.  

Now to retrofit this building I am considering having them saw cut and
remove the inner shell of the block from the inside, embed #4 bars into
the upper and lower bond beams with epoxy grout ,lapping the bars 30
inches, then gluing the shell back up to the course just below upper
bond beam, then filling the void with grout continuing up carefully and
adding the last shell and pointing the remainder.

What a mess, If anyone has a better idea I would sure like to hear it.
Adding shotcrete with a grid of steel to the interior is not an
alternative.

I would appreciate your suggestions.


David A. Hall, S.E., P.E.
Senior Structural Engineer
David Evans and Associates, Inc.
2828 SW Corbett Ave
Portland, OR 97201
503-499-0280
Fax 503-223-2701
E-Mail dahl(--nospam--at)deainc.com