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Re: roto-hammers, masonry & city of LA

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In a message dated 98-01-12 14:01:33 EST, you write:

<< Subj:	 roto-hammers, masonry & city of LA
 Date:	98-01-12 14:01:33 EST
 From:	cwec(--nospam--at) (Century West Engineering Corp.)
 Reply-to:	seaoc(--nospam--at)
 To:	seaoc(--nospam--at)
 we are planning on using a 'helifix' anchor system
 to retrofit a masonry building. The installation of these anchors
 requires the use of a pre-drilled hole in the mansory.
 During conversation with the anchor manufacturer, he stated 
 that the City of LA does not allow the use of impact or 
 roto-hammers on masonry retrofits. -This seems a bit restrictive.
 Has anyone heard of this? - if so, could you explain why?
 thanks in advance,
 Tim Terich
 Century West Engineering Corp.
 825 NE Multnomah, Suite 425
 Portland, OR 97232
 v(503) 231-6078 f(503) 231-6482

How good is the mortar in the URM and what is exactly your retrofit.  Are you
just anchoring the brick back to a new concrete shear wall to help prevent
out-of-plane failure by putting these anchors say at 24" o.c. each way.

You may still be able to use a low impact tool such as an MDR-9 drill which
does not have nearly the same impact as a rock drill. If you apply to much
forward pressure on the drill it binds, and stops drilling as opposed to a
rotary rock drill.  You may want to test an area of URM wall to see how bad it
actually is, and you can always do a test after the fact to see if there has
been any significant reduction in shear strength.

Michael Cochran