Timber piling axial capacity

[ckmck]

Question regarding axial capacity of altered driven timber piling. The 35-foot long, 10-inch diameter piling was driven 25 feet into a submerged sandy bottom. Realizing it was driven too deep, the contractor pulled the pile up 5 feet. Question: What is the effect on the axial capacity of the piling compared to if it had originally been driven 20 feet as specified?

 

[weab]

What effect? As you describe, it could be major. At a minimum, you have lost all of your pile tip capacity. In sandy soil, this is probably really bad news for you. You should only retain your skin friction capacity which sands typicaly have little of.

You need to get new pile capacity curves from your geotech. I expect that your new curves will only include skin friction and no tip capcity. In sandy soil, you may have virtually no capacity unless you are also driving through a good clay.

Good luck- I fear that you will need it.