Progress,  page 14
We have four courses of foam panels installed on the downhill retaining wall now, and the fifth
course will reach slab level.  The gray projections from the wall are poured concrete
reinforcements to help keep the walls from tipping over due to the weight of the dirt behind
them.  Brian (our engineer) calls them pilasters, a friend of mine calls them buttresses, I call
them gussets, and Dictionary.com calls them piers.  Whatever the name, they are massive and
strong, being made of rebar and poured concrete.  They are about 5 feet high, 6 feet long, and
roughly 10 inches (or more) wide.  I say "or more" because I didn't make the forms strong
enough and the weight of the concrete caused them to bulge.  Two of them have been poured in
this picture -- a third one in the background isn't completed.
Here's a look at the rebar
skeleton for the pier (I'll go with
the expert reference).  The
vertical rebar will be trimmed to
length and the forms built
around the skeleton, hopefully
more solidly than last time.  It
takes over a cubic yard of
concrete to fill each pier.  The
walls are very strong even
without the piers, but the length
of the walls (almost 30 feet)
might make them prone to
tipping over without the piers.  
Better safe than sorry.
From the REALLY
overkill department ...
This is a closeup of the
rebar connections between
the pier and the wall.  I
was putting so much rebar
in there that I had to
consider how to space it so
that we could get concrete
between them.

I don't think the wall will
pull loose from the pier,
though.