Digging out a crawlspace
Digging out a crawlspace
(OP)
I have a contractor who wants to convert most of his crawlspace into a basement (it is his own home). Enclosed is the detail we are tossing around. The soil is pretty stiff and he is doing this in small sections so he is not worried about stability during construction. My question is how to account for the surcharge load due to the existing house footing? Part of the footing load is being used to prevent overturning of the new retaining wall, but part of the load is adding surcharge. If the computed pressure under the existing footing is, say, 750 psf (service), what would you do?
Thanks
Thanks






RE: Digging out a crawlspace
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Digging out a crawlspace
RE: Digging out a crawlspace
Dik
RE: Digging out a crawlspace
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Digging out a crawlspace
RE: Digging out a crawlspace
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Digging out a crawlspace
If the existing footing rests on the edge of the wall, this is an eccentric axial load on the wall, which creates bending in the direction of the soil pressure.
RE: Digging out a crawlspace
See thread256-54204: Under pinning a foundation - need advice.
See thread256-361704: Row house basement dig out with underpinning
Search ET for similar threads. There have been several on the same topic.
www.PeirceEngineering.com
RE: Digging out a crawlspace
RE: Digging out a crawlspace
www.PeirceEngineering.com
RE: Digging out a crawlspace
RE: Digging out a crawlspace
All worked for a while, None worked well unless either the new construction was under the original wall (underpinned) or a proper retaining wall was built.
My Advise ... Either use conventional underpinning and concrete wall placement COMPLETELY supporting the old foundation or step inside about 1-1/2 to 2' and build a PROPER cantilevered retaining wall.
RE: Digging out a crawlspace
RE: Digging out a crawlspace
RE: Digging out a crawlspace
RE: Digging out a crawlspace
Dik
RE: Digging out a crawlspace
RE: Digging out a crawlspace
RE: Digging out a crawlspace