Foundation Walls Acting as Deep Beams between Helical Piers

[YoungGunner]

Project hit area with bad soil and geotech suggests using helical piers that support the foundation walls/footings. It was recommended to design the foundation walls between piers as reinforced concrete beams and thereby negate the need for footings. As I was looking into ACI about deep beams, I see a lot of stuff about design, but section 9.9.3.1 caught my eye about reinforcement spacings along the side faces. I get the feeling that my "foundation wall beams" are going to need double matts of reinforcement, both for vertical and horizontal rebar?

One thing I should clarify is that the heights of these foundation walls are between 4ft and 12ft. They are so deep I'm less concerned about the strength of the beam but more about whether that reinforcement still needs to be doubled.

 

[KootK]

I can see how that would be an awkward situation. Certainly, in the past, folks weren't enforcing the deep beam side face stuff for these situations in the markets where I worked. I cannot, however, think of what the appropriate "out" would be nowadays?

 

[Prestressed Guy]

How thick are the walls?

 

[skeletron]

What is the probable helical pile spacing? I would think that you would design as walls: horiz mat + vert mat, and then if t > 8" two curtains. I'd look at how the pile support (pin-support) affects the bending moment and reinforce continuous bars accordingly.