Piles going deeper than expected
Piles going deeper than expected
(OP)
Does anybody know of any good case studies where piles went significantly deeper than the borings predicted?
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Piles going deeper than expected
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RE: Piles going deeper than expected
RE: Piles going deeper than expected
RE: Piles going deeper than expected
Consultants were Posford Duvivier
Main Contractor was Kawasaki Steel (project manager Myoshi, assistant Ichise ) . Posfords (for Sabah Port Authority) argued that the increase in pile length (by about 5-10 metres for 390 piles) was the contractor's problem, Kawasaki proved otherwise, after a major investigation effort including British experts. I don't know if the results of arbitration was ever made public, probably some confidentiality clause.
The general principle appears to be that you cannot contract out risk.
Cheers
RE: Piles going deeper than expected
RE: Piles going deeper than expected
RE: Piles going deeper than expected
I'll conditionally disagree regarding "non-displacement" piles going on "forever." In my experience, this doesn't happen in "clean" silica sands with DR in excess of about 80 to 90 percent. I know that's pretty "dense" - but also fairly common in areas with OC soils.
The "forever" phenomenon can occur in soils with DR of less than 60 percent, though.
RE: Piles going deeper than expected
Best regards.
RE: Piles going deeper than expected
Quite often driving piles to "set" in granular soils can lead to longer than necessary piles. Rather than just keep driving piles deeper and deeper chasing a "set" why not stop at the design depth and record the blow count. Then carry out dynamic testing and CAPWAP analysis to find out what shaft friction and end bearing the pile has. If the pile test show the pile to have the required load then drive remaining piles to the blow count recorded for the test pile. Then carry out a bit more testing (say 5 to 10%) during installation of the remaining piles.
A properly engineered job with a bit of Quality Control as well, every one should be happy, including the insurance company.
Happy pile driving to everyone.
RE: Piles going deeper than expected
The resident engineer, with approval from design, switched to 14" tube piles with a 1 inch plate on the bottom. The piles then went less than designed depth, but still achieved desired bearing.
RE: Piles going deeper than expected
I'm surprised INDOT specified H piles in a non-end bearing situtation. They almost always dictate SEC piles in that case....