Tall retaining foundation wall, lateral support question

Started by carlsonNY, March 09, 2023, 11:14:44 AM

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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.



take this with a good grain of salt as one would say but - I have to openly question about how much fill there actually is on the low (right side) wall to offset the over-long-term force induced by the high wall pushing against the wood floor?



That floor diaphragm is lateral support. I am actually not sure if it 'resets' the unbalanced fill rule in the above link, but it seems reasonable. I would read section R404 and know it well before talking to the code guy.

Also assuming your attic joists sit at the top of the 10' wall section.


The 19' high concrete wall is supported on its sides by the suspended wood floor joist system, as shown in your diagram, which balances the excessive force exerted by the tall wall on the wood floor. Although that appears sensible, I'm not really sure if it'resets' the uneven fill rule.


The design of the concrete retaining wall itself should incorporate appropriate engineering principles, such as proper reinforcement, adequate footing, and wall thickness, to withstand the lateral soil pressure.