Skin Friction Concrete Pile (5' Deep)
Skin Friction Concrete Pile (5' Deep)
(OP)
I have two similar projects in regards to the depth of foundation and its skin friction resistance, one of them are 12'-0" 12" diameter piles for a storage building and the other is a 5'-0" 12" diameter concrete pile for a deck. For the storage building, I have a soils report and I have to exclude the first 5'-0" of soil leaving very little capacity for the storage building. Now excluding the first 5'-0" is a general practice that I've used many times for many different types of buildings but for a small storage building I have a hard time rationalizing needing to go almost 18'-0". Now on the other project where the load is minimal and a 5'-0" pile, using the same principle the pile has a capacity of 0 which is obviously wrong. At what point can we start rationalizing using part of the 5'-0" soil at the top. Thanks in advance for any insight.






RE: Skin Friction Concrete Pile (5' Deep)
RE: Skin Friction Concrete Pile (5' Deep)
Dik
Dik
RE: Skin Friction Concrete Pile (5' Deep)
RE: Skin Friction Concrete Pile (5' Deep)
In regards to jgailla how would I ensure that at the bottom of the hole, most likely hand augered, is flat so that I can use the full bearing area? If the end is augured it will most likely be cone like would it not?
RE: Skin Friction Concrete Pile (5' Deep)
RE: Skin Friction Concrete Pile (5' Deep)
The important thing on any footing or end bearing pier is that it rest on undisturbed soil, so that it doesn’t have to compact and settle an inch or so before it really starts bearing. As others have said, I would not consider skin friction on these short piers, but it might be enough to hold the pier up a bit during early construction; in such a way that it would not settle down until more fully loaded, and you do not want that. The soil at the footing bearing elev. or the bottom of the augered hole should be hand dug to get to undisturbed soil, it should not be 6" of loose soil clods (backhoe teeth or auger teeth, etc.), which will compact when really loaded. We always had a gen. note on footings, etc. that they should bear on undisturbed soil and that all organic material should be removed.
RE: Skin Friction Concrete Pile (5' Deep)
You are on the wrong track with this. A hand augered hole can't be more than 6 inches in diameter.
What kind of support are you expecting with a 6 inch diameter pile 5 feet deep?
RE: Skin Friction Concrete Pile (5' Deep)
Dik
RE: Skin Friction Concrete Pile (5' Deep)
There is also some skin friction but we would negate that due to perhaps a high variability and uncertainty.
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RE: Skin Friction Concrete Pile (5' Deep)