In article . com,
wrote:


Piles don't have to reach "bedrock" to work. Friction can hold them
in place.
Just spotted something.

Both New Orleans & Lake Pontchartrain are on the Mississippi delta,
with Lake Pontchartrain being on the North side of New Orleans.
Sediment under Lake Pontchartrain is reportedly 20,000 feet
deep .... the bedrock is under that, as the oil drillers know.
I don't recall any mountain-building processes in the area that
would have created a 20,000 foot tall mountain under the site of
New Orleans.
So I'd guess that your 80 foot number just applies to how deep
pilings are driven for some purposes and has nothing to do with
your assumed bedrock depth.



You need an education, boy.

Building foundations need only be sunk to the point where a building is
floating.


--Tim May