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RE: Partially grouted CMU walls in seismic areas

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Using solid grouted walls in ALL regions just because it is perceived to be
less likely for a contractor to screw up is excessive.

In ICBO and SBC jurisdictions (where inspection is required and 1/2 stresses
are not allowed) partially grouted walls are common, and generally
constructed correctly.

I do hold that in regions where solid grouted walls are the rule, use fully
grouted walls.  It is best not to fight the trend.  And where partially
grouted walls are common, I use partially grouted walls.

In international work, I use the indigenous rebar grade and sizes.  In areas
where good carpenters are scarce I avoid split ring connectors.  In areas
where qualified welders are scarce, I avoid field welding.  

You should design what you need based on the regional construction
practices, for the superimposed loads, and for performance (like tornado
missile impact).

The most critical issue is special inspection.  It should be required for
all masonry construction regardless of high lift, low lift, partially
grouted or fully grouted.  The 1/2 stress allowance with no special
inspection creates a false sense of security.  An ungrouted cell will not
perform.

Regards,
Harold Sprague, P.E.
The Neenan Company
harold.sprague(--nospam--at)neenan.com