Negative skin friction on end bearing piles.
Negative skin friction on end bearing piles.
(OP)
In the case of an end bearing pile founded on 'bedrock', placed thru a compressible layer called 'clay' with a fill material placed over the clay, just prior to driving, and the clays resultant consolidation causing down drag-negative skin friction = additional load on the pile. Is this additional load a permanent load or does it dissipate with time? Assuming the pile tip and the rock can carry the load.





RE: Negative skin friction on end bearing piles.
Note that much has been written on dragdown on the recent years (notably Fellenius) but these are piles in soil on soil.
RE: Negative skin friction on end bearing piles.
The location of the neutral plane is a function of the load distribution in the pile which only includes the dead load.
You can download many of Fellinius's papers:
http:
RE: Negative skin friction on end bearing piles.
RE: Negative skin friction on end bearing piles.
Assuming the load can be adresses by the pile, is this a permanent, sustained, long term load on the pile? Or does it dissapate with time?
RE: Negative skin friction on end bearing piles.
RE: Negative skin friction on end bearing piles.
So for dead load, and maybe a portion of live load, yes the drag load is permenant. Note that drag loads occur in all soils and not only soft or compressible soils.
As Big H noted the piles must be structurally designed to carry the drag loads, or coated to reduce drag loads.