Concrete-Filled Pipe Pile(composite Pile) Testing Method 1

[TTTKAO]

Hello All,

I am preparing for a test method spec for Concrete-filled Pipe Pile, the pipe pile will be driven to the top level of rock firstly, and then drill soil into the rock 3m further and fill the reinforced concrete. The pipe pile need sharing resistant load with reinforced concrete core pile. i have a few items wondering could get some advice and experience sharing from you.

1. is the static load test necessary? it seems PDA is a trend for the test which can save time and cost for client. i can't find any code or specification stating the static load test is a must for composite pile. wondering what you did before for the similar situation.
2. for PDA test, is it necessary to do the pipe pile test and concrete core pile test separately? or PDA can do one-time test for this composite pile ? i didn't find clear answer on ASTM D4945, but from my understanding PDA can take one time test for the composite pile
3. if PDA is required, is integrity test for concrete core pile still required as well?
4. For tension capacity and lateral capacity test? is this commonly required on piling project, I designed a few piling foundations before, never required this test.

Thank you!

 

[LittleWheels]

A pipe pile with a rock socket is commonplace in my industry. Sometimes the pile is completely concrete filled and sometimes the rock socket and pile plug do not have concrete continuously between them.

Strictly speaking, in several codes, a PDA test needs to be calibrated against something. Usually that something is a static test.

A PDA test involves the entire pile as installed during the test.

A pile integrity test is not required if you have conducted a PDA. The PIT will not provide any additional or better quality information than a PDA.

Tension and lateral capacity tests of piles are not common but not unknown. The benefits of conducting those tests depends on the loading the piles will be subjected to and how they were designed.

 

[TTTKAO]

Hi LittleWheels,

Thank you a lot for sharing. i have a few questions to your explanation, wondering could you help to share more details?

What does "rock socket and pile plug do not have concrete continuously" mean? the pipe pile will be driven first, and then soil plug will be removed. do you mean only fill concrete at the bottom part and fill back soil to the top of pipe pile ?

if the reinforced concrete fill to the top of pipe pile and the rebar will extend out of pipe pile, is the rebar an obstacle to do the PDA for composite pile ? wondering is there risk to break the bond between steel pipe and concrete pile due to PDA test?

Thank you so much for kindness.

 

[LittleWheels]

A PDA test determines the load capacity of the pile and soil/ rock. Whether the pile is completely concrete-filled doesn't usually change that, once the rock socket is poured. The exception is if the steel is sacrificial permanent formwork. Most of our piles rely on structural steel.

The rock socket (and lowest part of the steel pipe pile) would be concrete-filled. The region above could be sand-filled or left hollow (actually filled by water in my industry). A separate pile plug is generally not poured until after the PDA test. The lack of a pile plug does not affect the pile's load capacity assessment by a PDA.

If you want to test a concrete-filled pile, you can do so by leaving the pipe over-long and cutting the pipe to length after the PDA test.

I have never had any concerns about breaking the bond between steel pipe and concrete rock socket once the concrete has reached strength. Doing a PDA the day after pouring would be quite a different situation.

The chances of a concrete defect within a steel pipe is very small. You would have to have a pretty significant construction problem (usually a rock socket issue only) e.g. massive cold joint mid-pour (could be within the pipe), poor cleaning of rock socket, poor seal between steel and rock allowing debris into the rock socket after cleaning.

 

[TTTKAO]

HI LittleWheels,

Thank you so much for the further details. now i got it clearly. Appreciate the help.