GPR is your best bet
D. Matthew Stuart, P.E., S.E., F.ASCE, SECB
Senior Project Manager
Structural Department
Associate
Engineers and Consultants - CMX
200 Route 9
Manalapan, NJ 07726
732-577-9000 (Ext. 308)
908-309-8657 (Cell)
732-298-9441 (Fax)
mstuart@CMXEngineering.com
From: Thor Matteson [mailto:thorm@sti.net]
Sent: Thursday, April 30, 2009 10:43 AM
To: seaint@seaint.org
Subject: Re: CMU California Practice in the 1950's
Sorry if this is repetetively redundant by now--tried to send on Monday, but was having list issues. Have not seen other comments on "sounding" CMU walls to find un-grouted vs. grouted cells.
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Harold,
You can tell by "sounding" the wall which cells are grouted. Tap the wall with a hammer--the grouted cells sound very different than the ungrouted ones. Note: If you're not on site, this method doesn't help you much....
I inspected a CMU addition in Lompoc built in the 50s or 60s and it was only grouted where the reinforcing was.
One reason solid-grouting became common is that it's less labor-intensive than blocking off the cells below your horizontal reinforcement--plus you can do high-lift grouting instead of having to grout every horizontal rebar course before continuing to lay block. If you're using ready-mix trucks, you only bring them in once for grouting when the wall is topped out.
Best wishes,
Thor Matteson
www.shearwalls.com