How to check actual height of pile as constructed

[ABA102]

Hi Geotechnical experts,

We have a situation on our site that we suspected the actual height of pile is not as per the design. The integrity test report was submitted but doesn't specify that the height was actually checked other than the integrity of the piles. I have searched that there is a certain calculation to determine the actual height of pile based on the velocity and time as per the actual test carried out. Can anyone clarifies my doubts and unselfishly share his knowledge. Thank you in advance.

 

[MotorCity]

What type of pile? If its a driven pile, check with the pile driving contractor. He should have records for each pile. Typically, the pile is marked on the side to record the driving depth. Take a look and see if there are any markings on the pile.

 

[ABA102]

@MotorCity

Its a bore pile. Sorry to say that i was not really properly checked during construction. Actually, we are investigating it since it appears that the dowel bars are longer than height should be. The testing laboratory submitted the integrity test report but there is no calculation showing that the pile height is correct as required. instead only certifies he integrity of the file is okey.
Is there any formulation to counter check the actual height using the velocity and time obtained on the integrity test report?

 

[WARose]

Probably the most accurate way I've seen is Ground Penetrating Radar. I've used that verify driven depth for existing structures (where I didn't have drawings).

 

[spieng89]

In your case of post construction, a NDT i.e. Dispersive Wave Propagation Test might be your best bet. A few companies have patents to use there specific wave testing to determine things such as pile depth

 

[JGard1985]

I wonder if you could use UT to determine length of pile, similar to how UT is used to measure thickness of piping, pressure vessels and tanks

Jeff
Pipe Stress Analysis Engineer

http://www.xceed-eng.com

 

[WARose]

In your case of post construction, a NDT i.e. Dispersive Wave Propagation Test might be your best bet. A few companies have patents to use there specific wave testing to determine things such as pile depth

Be advised that sometimes those tests can be somewhat inaccurate. (Because the reflection time is affected by the soil-pile interaction.) There has been a lot of talk (lately) about that new "EDAR" method. (I.e. that it is highly accurate.)

 

[oldestguy]

If this is highly critical, consider running a load test on one. It would also help verify your estimates of the support capability. Cost should be borne by those that didn't stand there and measure things on the job as it was done. Next time use the word "length" not height.

 

[ABA102]

Thanks everyone for your contribution. I will try to discuss ti the contractor what applicable examination they can offer considering accuracy.
But for the meantime, may I ask anyone for an applicable calculation that I can use with the data given on the result such as the velocity, the time and the hertz of the integrity test.

 

[Guest262653]

The following paper may help:
[URL unfurl="true"]http://www.ndt.net/article/defektoskopie2009/papers/Rybak_Schabowicz-8.pdf[/url]

 

[ABA102]

@ avscorreia
Thank you very much. This paper you shared can be really a helpful to my investigation.

 

[Ron]

Low frequency pulse echo techiques work well for this application.

I did some research over 20 years ago, along with one of my geotechnical colleagues, into a method of pile length determination using an electromagnetic field response. We wrote a paper on the technique that was published in the Deep Foundations Institute Conference Proceedings in 1996. Here is the citation on the paper:

Woods, W. Ronald and McIntosh, Kirk A.,"Electromagnetic Pile Length Determination", Proceedings of the Deep Foundations Institute, National Conference, October 1996.

The proceedings are available through the Deep Foundations Institute if you want to get it.

DFI would be another good source of info for your issue. Check their other publications.

 

[ABA102]

Thanks Ron.