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Re: Masonry Structural Notes and Specifi

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Chris,

Writing specs for high lift grouting can be very demanding.  While 
masonry contractors experienced in high lift grouting understand the 
difference between "lift" and "pour," other masonry contractors do not.  
"Lift" and "pour" need to be carefully and prominently defined.

But, getting back to your basic question, cleanouts are intended for two 
purposes; to be able to visually inspect reinforcing to see if it is fully 
lapped, and to clean out mortar droppings, therefore cleanouts are necessary 
at the bottom of each pour.  If the pour height is such that a worker can 
reach down and clean out the cell, a cleanout is not needed.

If you have a fully grouted cmu wall, all cells must have cleanouts.  If you 
have a partially grouted cmu wall, only grouted cells need to have 
cleanouts.  Mortar droppings are weak and need to be removed from cells 
at the bottom of each pour.  Mortar fins in grouted cells have to be knocked 
off as they provide a ledge for grout to hang up on.

I *permit* contractors to use lintel block at cleanouts, with the block 
installed flat, instead of vertically, as this eliminates the labor intensive 
chore of cutting the face shell off cellular cmu.

You probably should also include something that will indicate to a contractor 
that he/she has reached each lift height, such as a small weep hole type of 
tube that will permit grout soup to come thru when the grout reaches that 
level.

Although not included in masonry special inspection requirements, I believe 
that high lift grouting should require continuous special inspection.  Once a 
wall gets up to full pour height, it is difficult to determine if vertical 
reinforcing positioners and all horizontal reinforcing have been installed 
and more difficult to correct.

HTH

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Christopher S. Campbell wrote:

. > I have been put in charge of re-writing the structural notes for masonry
. > construction for our office.  For just about every detail of masonry I
. > can find either code or text to describe the method and requirements.
. > The one part that I am missing out on is the requirements for
. > clean-outs.  If high-lift grouting is allowed, and the grout is
. > consolidated and re-consolidated, how often do cleanouts have to be
. > placed?  I understand that there are vertical as well as horizontal
. > requirements. 

. > The other part of this that bothers me is that there appears to be a
. > limitation in that you may not need to require cleanouts at all, even
. > with high-lift grouting, but again, the limits of that are completely
. > unknown here. 

. > Our typical masonry construction uses are in retaining walls - mostly
. > under 6' in height.  I want the requirements and limits to reflect our
. > needs mostly, but also make sure that I understand the needs to
. > clean-outs.

. > Thanks.

. > Chris

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