Pullout test on driven pile
Pullout test on driven pile
(OP)
Hello,
We made an pullout test (ASTM D3689)on a driven pile with success. The criteria used for the acceptance of the pile is the elastic lengthening + 5mm. I calculated the elastic lengthening with PL/AE, but the bridge engineer says that the elastic lengthening should take into account the soil resistance!? I do not agree with that, but the piles are not accepted until we can give an answer to that, and I do not have arguments. I do not know where to begin either to calculate the ''elastic lengthening'' taking soil resistance into account....
The pile is 14'' diameter pipe pile with 0.375'' wall thickness (356mm x 9.53mm).
Anybody has input to direct me??
Thank you very much in advance.
Jonathan
p.s. You can find the test data joined (in french but it's mostly straightforward)
We made an pullout test (ASTM D3689)on a driven pile with success. The criteria used for the acceptance of the pile is the elastic lengthening + 5mm. I calculated the elastic lengthening with PL/AE, but the bridge engineer says that the elastic lengthening should take into account the soil resistance!? I do not agree with that, but the piles are not accepted until we can give an answer to that, and I do not have arguments. I do not know where to begin either to calculate the ''elastic lengthening'' taking soil resistance into account....
The pile is 14'' diameter pipe pile with 0.375'' wall thickness (356mm x 9.53mm).
Anybody has input to direct me??
Thank you very much in advance.
Jonathan
p.s. You can find the test data joined (in french but it's mostly straightforward)





RE: Pullout test on driven pile
At 1000 KN, Calculated Elongation Subtracting Soil Resistance = 18.4 MM. (Compared to the measured 12.77 MM)
I've worked with your data the old way (paper / pencil, graphical approach). See the attached 4 pages (8.5 megabytes, sorry).
Page 1: The higher the load, the closer measured elongation approaches theoretical elongation (31% @ 50 KN compared to 55% @ 1000 KN). This is reasonable. Under light loading even theoretical elongation is not enough for the pile to "break free" of skin friction at any location. As load increases, elongation slowly allows more and more of the pile to break skin friction. You can make use of this trend.
Page 2: At 1000 KN, skin friction is minimal (for the test range of 0 KN to 1000 KN). Look at the last test increment (950 KN to 1000 KN). For a 50 KN increase in force the pile elongated 0.92 MM. Draw a line with that slope all the way from 0 KN to 1000 KN. That line predicts pile elongation IF soil resistance had been constant at the minimal test value observed (from 950 KN to 1000 KN).
Page 3: This graph is just a check of Page 2 to make sure that a data collection error did not invalidate the Page 2 calculation. Result was a reasonable, slightly lower calculated elongation = 17.2 MM.
Page 4: Another check, exactly the same as Page 3, but using even more data. Result, as expected, a still lower but reasonable calculated elongation = 16.4 MM.
Review the graphs, it is difficult to provide a word description. Realize these results apply only for the 0 KN to 1000 KN test range, not a general solution. This proposal makes use of available data - no doubt a more accurate solution can be obtained... but only by performing additional (expensive) tests.
Questions or Comments welcome.
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RE: Pullout test on driven pile
Your input on my problem is extremely helpful!
RE: Pullout test on driven pile
RE: Pullout test on driven pile
The test showed in the elastic condition, the permanent deflection is 0.66mm and it was not failure yet. The elastic deflection (PL/AE) is only valid if soil resistance is measured.
The load is P at the ground surface and it is zero at the end/tip of the pile.
RE: Pullout test on driven pile