Tall retaining foundation wall, lateral support question

[CarlsonNY]

Hey guys,

I am designing a house that will be built into a pretty tall ledge rock/clay which means I need a tall concrete retaining foundation wall. I am attaching a drawing to help explain my question: Does a hung wooden floor joist system as pictured in my diagram count as lateral support to my 19' tall concrete wall? Is there a better way to construct this idea of a basement + 1st floor that needs to hold up to 19' of soil pushing against it?

Please let me know if you need more data to be able to answer this question and I thank you all very much for reading.

 

[driftLimiter]

Let me start by saying this is more than a pretty tall wall. Its pretty much a monster retaining wall.

The wood floor system can act as a support if it has sufficient strength and stiffness. Would need to analyze the whole building and see if you can get enough strength/stiffness from the wood system to support your wall.

This most 100% definitely requires the careful design of a qualified structural engineer. More than likely I would expect the wall needs to be supported by some other means. Such as soil nails, counterforts, piles or mat foundation.

Other option may be to use geofoam as backfill of the wall to help reduce the lateral pressure.

 

[CarlsonNY]

Thanks drift Limiter. I figured this wasn't gonna be a walk in the park to construct and I appreciate your ideas and knowledge. It might just make sense to not include a basement and build this on slab on grade. Here is a sketch of that.. still a tall retaining wall but more of a baby monster.

Would you have any thoughts on this?

 

[driftLimiter]

This configuration appears to be a bit more conventional. Again it depends on the wood system itself whether it will be sufficient to support the top of the retaining wall.

Something else to consider with this arrangement is how the shear at the bottom of the back wall flows.

It can be resisted by the soil, but that soil ends up pushing on the shorter retaining wall in the back. This isn't something that is necessarily prohibitive, but would be good to address.