How Do I Measure Length of a RCC Pile After it is Driven

Any chance you knew how long they were before they were driven?

Yeah sure, hire a licensed surveyor to determine the pile top elevation.

Didn't anyone conduct a Pile Driving Log for each pile driven on the Job Site where the blow count vs pile depth were recorded? An experienced field inspector or Junior Engineer should have done this. After the fact is not a good excuse, especially to save some money on the project.....

Well, if they are concrete piles, someone must have ordered them, and then somebody made them from the order...

"Is there any technique to measure the length now?" What length?

[edit] Is there a concern piles were driven in the incorrect locations? That is to say, piles adding up to a 17 meter length driven where a 19 meter pile is scheduled?

thanks. there is an apprehension that the piling contractor did some mischief in collusion with site engineers. now, it is to be verified

shantanoo,

The only method of determining the depth of a pile after it has been installed is to excavate down and measure it. This is not a wholly satisfactory method as it removes the frictional capacity of the pile, but could be performed on a small number of piles to appease your apprehension.

Your real problem is to know the capacity of the piles. For this you can do either a static or a dynamic pile test. Static is when you put a load on the top of the pile and measure the displacements. Dynamic is when you hit the head of the pile and measure displacement. If the piles are within capacity then you should be safe. You probably have pile testing somewhere in the specification or in a reference to piling good practice. You can also consider using ultrasounds to measure the length of a pile. This is used to measure pile integrity for cast in situ piles and may be possible on your driven piles depending on the type of joint you have between pile sections (if you have sections that is).

Ultrasonics comes to mind. Unless the concrete pile is driven into concrete, you should be able to find the end.

Don't ask me how, I'm just the idea man.

Well, lynlynch, if you can tell me how this can be accomplished, I would love to know because, at the moment, the depth of a pile, so far as I am aware, is not something which can be measured by any standard device other than a tape measure. If you know otherwise, please inform the ignorant masses, including me.

To all of you other forum members, if you can up with an answer to this problem, you will not have to work for the rest of your lives.

"...if you can up with an answer to this problem, you will not have to work for the rest of your lives."

Bruce, I find this an interesting comment. Is the verification of placed piles a large enough issue that piling logs, the piling manufacturer's order, fabrication and ship records, etc, are not sufficient? Does the concern extend to other undergound placements as well?

In this circumstance, our OP has a reason to suspect some shenanigans; is that a common concern, or is this a one-off issue?

Not having to work again appeals. After all, I once married a pregnant woman.

Doorman,

In my area, drilled cast-in-place piles are frequently used. The native soil is predominantly glacial till. Piles may be friction piles (straight shaft) or bearing piles (belled bottom).

For commercial projects, inspection is usually continuous during the installation of piles, so it isn't a problem. For single family residential projects, the contractor frequently installs piles without notifying the engineer, so the depth of pile is unknown.

I am currently in a legal battle with the county (authority having jurisdiction) for a report I wrote on Jan. 4, 1994 respecting a foundation for which the county granted a building permit when the house was about 90% complete. The county was sued by the third owner of the house because the foundations heaved in the winter and settled in the spring. The amount is $300,000 plus costs. The county has third partied my firm.

Without going into detail, the county's lawyer contends that my report warned of possible frost movements, but I should have inspected the foundation when writing my report, notwithstanding the fact that the foundation was built a year and a half before I was retained.

I have taken the position that I could not have determined the depth of piles by any reasonable means and saw no reason to attend at the site...meanwhile the lawsuit continues and the lawyers are all laughing their way to the bank.

If there is an easy method of determining the depth of a pile, my argument loses validity. At present, I am not aware of one.

Thanks for the response ba/ael.

The projects I am most familiar with are commercial and industrial projects in USA. As you say, there is ALWAYS an inspector or two hanging around making notes about something. This practice makes our discussion here very uncommon.

I saw a load of piles leaving that job-site. About three hours later, these same piles turned up on another job-site across Town. Go figure.

The reason may be that the driven piled achieved the required resistance as measured by their displacement compared to the hammer blow. Once they have achieved this value the pile does not need to be extended. Hence the additional pile lengths can be shifted to another site. If anyone can be bothered to read my previous post it might save some time.

Maybe I'm wrong, but it seems to me that there should be some way to sense the reflected energy that is bounced back from the end of the piling, since there would be, I think, some discontinuity at that point which might reflect some energy back up the column.

Maybe whacking one end with a hammer and timing the return of the acoustic energy.

Maybe I'm the one who is ignorant, and it wouldn't be the first time.

"Maybe whacking one end with a hammer and timing the return of the acoustic energy."

Careful there, partner. If you give away all of our secrets, we will have to live off of income from our SSD formula and our over-unity devices.

Sorry there, I got carried away.

If I knew where the piles were I just might take one of the LynDoor™ Industries, Super-hydrodyne Whacker Doodle^® Pile analyzers over there have a go at it.

_{On another note, the Guests are getting downright surly. Jeez, you'd think they paid our salaries.}

Try googling integrity pile testing.

Does omw7 stand for 'Oh My Word'?

Wikipedia excerpt: "The PET system utilizes the pulse-echo method. To test a pile, the user strikes it with PET's lightweight handheld hammer. The resulting signal, or reflectogram, is captured by PET's digital accelerometer. It is than transmitted to the computer to produce information about the pile's length and shape."

The article sort of reads like an advertisement, and it certainly sounds like what OP is looking for. Well done!

I guess I will have to keep my day job at Lyndoor™ Industries.

[edit] Regarding your #17: You are correct. I for one did not read your comment as closely as I should have.

for me.

there is usually a local a independent testing laboratory that is familar with this sort of thing. i'm sure they can give you the answer for your question. as far as i know, piling is driven down to bedrock. they should never settle reguardless of the weight applied in a vertical application

Yes, the old Pile Integrity Testing technique....

https://www.grlengineers.com/services/integrity-evaluation/pit/

https://www.pile.com/resources/faqs/faq-can-pile-integrity-tester-used-evaluate-length-defects-piles-supporting-existing-structures/