Guys,

We are excavating a full basement, about 4000 ft².  10' high, 9' unbalanced fill.  The foundation walls will likely be quadlock 12", transition to 6" via their brick ledge tie about 1' above grade.  4000psi mix.  Normal soils (easily 2500 psf bearing).  The house sits on the knoll of a hill.  It is not holding back any earth other than the backfill itself.  The engineer is calling for double row vertical reinforcement with #5's for inner face and #4's for earth face ( I forget the OC spacing).  Any body ever had install this?  Issues with consolidation?  Our codes are seismic c.  Apparently the thickness of the concrete requires double row of vertical steel.

Opinions???

Your engineer is correct.

Generally 10" and up requires double mat of steel and in some instances 8" as well depending on certain conditions.

You should also be using a 3/4" stone in your mix, so make sure you have a min. of 3/4" between your steel and forms.

Vibration will not be an issue.

Chris,

Thanks....my engineer is very competent. I am glad to hear that the double mat will still consolidate well. It is funny that a friend of mine showed me a quote for a typical foundation basement with 2 story construction (sticks) that the foundation crew did not specify ANY steel. They said that the foundation wall is thick enough.

Don't laugh, where is your friend?

Many places have no rebar in foundations believe it or not.

Ontario as an example has no rebar in PIP 8" walls and certain states are the same.

Since ICF is an engineered product even if you go 8", the BI is usually looking for the bar.