Yazoo Clay
Yazoo Clay
(OP)
I am designing a 4 story wood structure approx. 60' x 300'. We are sitting on yazoo clay and I was wondering if anyone could help with the typical foundations seen on Yazoo (Jackson, Mississippi). We are trying to decide between piers (auger cast/drilled) with an elevated floor and crawl space or 10'-12' of over excavation then replacing with structural fill. I have read that both can still have issues. I am seeing heaving up to 30" in crawl space situations on one hand and then recommendations of up to 20' of over excavation on the other. Is there a typical system that is "tried and true"?
Respectfully,
Joshua Thorpe
Respectfully,
Joshua Thorpe






RE: Yazoo Clay
RE: Yazoo Clay
RE: Yazoo Clay
RE: Yazoo Clay
RE: Yazoo Clay
If it is indeed Yazoo clay that comes back in your boring logs (I have designed buildings in the Jackson area, so there is a good chance),the typical foundations there are bell bottom piers supporting grade beams (void formed). The geotechs in that area are very knowledgable in this regard and will give good recommendations.
RE: Yazoo Clay
Another system to consider is steel auger piles. But these need to be coordinated closely with your SPT results so that you terminate the ends well beyond the active clay zone, but if done right, they have some great uplift resistance. They are fairly inexpensive and fast to install.
RE: Yazoo Clay
Back to the Yazoo issue. Over-excavation is expensive and time consuming. If a deep foundation alternative is chosen, I would suggest that you use a system with low skin friction in the clay region to prevent inordinate uplift stress on the deep foundation system. Casing past the clay region is a consideration, with a combination of augered concrete piles below the casing.
RE: Yazoo Clay
This P.E writes a nice summary of what to think about.
http://thecosmiccorner.blogspot.com/2013/01/design...
RE: Yazoo Clay