Non-destructive confirmation of bored pile capacity 1

[LRJ]

I'm involved in a project where the client plans on installing bored piles. These have been designed according to the relevant standards for the area they will be installed in, but there is some suggestion that these capacities should be confirmed post-construction.

Some static pile load testing has been performed at an adjacent site to assist with design method calibration. However, the client cannot undertake such testing at the actual site due to project constraints (time, money, etc.).

So my question is: how can the axial pile capacity be confirmed using non-destructive tests?

My initial thoughts:
[ul]
[li]Derivation of axial pile capacity from drilling logs: there are several methods which aim to do this and might provide some indication;[/li]
[li]Low strain dynamic pile test: I'm not so familiar with the ins and outs of undertaking this sort of test, but I understand it is fairly standard, though cannot be used to calculate capacity (only length confirmation and the possible presence of voids, so would be quite indirect at estimating capacity if these results were used with other measurements);[/li]
[li]Full 're-strike' test: the trouble with this is that the interface would become damaged, since the piles were not originally driven, hence couldn't really be considered 'non-destructive'. Ultimately it is also based on inference like the other methods, so I would expect it is the worst option to consider.[/li]
[/ul]

Are there any more methods? What method is most common? How do these methods work? Are there any good references for such capacity confirmation methods of bored piles?

 

[oldestguy]

Standard pile load test per ASTM. D-1143

 

[LRJ]

Do you mean undertaking a suite of static pile load tests (i.e. a destructive test) to confirm the capacity? What exact ASTM standard? As per my previous post, this if this is what was meant, then it is not feasible to undertake due to cost and time constraints, hence asking about non-destructive alternatives.

 

[oldestguy]

Of course it costs to run the load test, but it does not cause the pile to be ruined for use. It might not go to failure if twice the design load is found to be OK. Perhaps there is local use of that pile where tests have been run and found to be usable on this site. Unless you are familiar with similar sites and similar non destructive tests, why take the chance? Add a few piles and apply lighter design loads. Still costs to do that.

In deciding what to do,check your errors and omissions insurance. Some times these things take priority.

Edit: In my experience we usually only do one test at a representative part of the site.

 

[r13]

The linked article address how to calculate load carrying capacity of CIP pile in cohesive soil. Read on. Link

 

[r13]

Here is another more detailed/involved article. [link file:///C:/Users/Kai%20PC/Downloads/Wrana-2015-4%20(1).pdf]Link[/url]

 

[Retrograde]

If by full 're-strike' test you mean a PDA test - this would be significantly cheaper and quicker than a static test in my experience.

Normally if doing a PDA test on a bored pile you would build-up the top of the pile for the test (essentially cast a short section of pile above the ground) and then break it back down when the test is finished.

You could always just design the piles with a large factor of safety and don't do any load tests.

https://www.pile.com/products/pda/