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Re: Masonry: Epoxy-injection for shear repair?

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> From: Sprague, Harold O. <SpragueHO(--nospam--at)bv.com>
> To: 'seaoc ' <seaoc(--nospam--at)seaoc.org>
> Subject: RE: Masonry: Epoxy-injection for shear repair?
> Date: Tuesday, August 26, 1997 8:27 AM
> 
> Michael,
> 
> Call Mike Schuller of Atkinson-Noland & Assoc. 303-444-3620.  Mike is
> very knowledgeable in masonry repair and epoxy injection.  Mike has also
> developed  a method of grout injection (Re: Masonry Construction, Sept.
> 1996).  The contractor that has actually repaired several masonry walls
> using grout injection is Hunt Valley Masonry of Baltimore 410-683-0177.
> 
> The grout injection method involves drilling and porting similar to
> epoxy injection, but the material is a fine grout which has properties
> compatible with the masonry.  Epoxy is much harder than the masonry and
> is not all that compatible with masonry.  Mike has some fairly
> impressive data on masonry walls that were constructed, cracked,
> repaired, and tested.
> 
> Additional references:
> Proceedings "International Brick Masonry Conference 1991, "Strengthening
> and Durability of Decayed Brick Masonry Repaired by Injections, by
> Binda, Baronio, & Fontana.
> 
> ASTM STP 992, 1988, "Masonry Cracks: A review of Literature", by Grimm
> 
> City of LA RGA #1-91, "Crack Repair of Unreinforced Masonry Walls with
> Grout Injection", May 22, 1991.
> 
> Regards,
> Harold Sprague
> Black & Veatch
>  ----------
> From: Livingston, Michael
> To: 'seaoc'
> Subject: Masonry: Epoxy-injection for shear repair?
> Date: Monday, August 25, 1997 6:46PM
> 
> I'm evaluating a 10-story masonry apartment building built in the early
> 70's where the walls sustained cracking from both the Loma Prieta
> earthquake and differential settlement.  About 5 years ago, it was
> "repaired" using epoxy injection.  I'm trying to track down which
> product was used without much success.  Apparently the criterion was to
> fix all cracks you could stick a credit card into and call the rest
> "cosmetic".
> My question:  Are these epoxy injection methods effective for restoring
> shear capacity of masonry walls?
> I've talked to some manufacturers who say it is great, stronger than the
> surrounding masonry, etc. but who were not forthcoming with test data.
> A colleague of mine suggests that for every crack, there are many more
> micro-cracks just waiting to open up nearby.  And where there is a
> visible crack, the steel may have yielded, reducing the capacity of the
> wall if steel was used to resist shear.
> Does anyone have any opinions/data on this method of repair?
> 
> Michael Livingston, SE
> michael.livingston(--nospam--at)intres.com

I was really surprised to read this note regarding Mike Schuller's
invention as published in Masonry Construction in September 1996 because,
in fact, this system was perfected through the 3-4 year long efforts of the
Hazardous Buildings Committee of SEAOSC following the Whittier-Narrows
event in 1987.  
Through the unsung volunteer efforts and contributions of men like SEAOSC
members Ray Steinberg, John Kariotis, Nels Roselund, Dave Breiholz, Dave
Taubman, and City of Los Angeles personnel Scott McGill, Karl Deppe, Doc
Nyguem, myself and many others, a small Los Angeles company, Ace
Repointing, was able to develop and patent an injection nozzle to monitor
and regulate the injection flow and pressure for this system.  Much
destructive testing proved the lateral movement of the grouting was
significant enough to fill many of the voids and, in that manner, restore
an unquantifiable amount of the lost structural stability of the damaged
unreinforced masonry wall.This resulted in the adoption of the referenced
City of Los Angeles RGA 1-91 in May 1991, "Crack Repair of Unreinforced
Masonry Walls with Grout Injection"
Just thought a little credit was due to those that put out the big effort
although I don't mean to minimize whatever efforts Mr. Schuller may have
invested; hopefully he was able to utilize our research and further the
initial developments.  I look forward to reviewing the Masonry Construction
article and the proceedings from the 1991 Conference.

R. Sandy Pringle
Structural Inspection Consultants Inc.
(800)598-1970