Tension Pile Load Test
Tension Pile Load Test
(OP)
I have a requirement to conduct a tension pile load test for a test load of around 650tons. I want to know the most reliable way of tying the pile to the test beams for the pull. Recently I tried using prestressing cables for a test load of 515tons. The problem in using these is the elongation. The hydraulic jack a has limited stroke and the cables are pretty elastic. I am planning to make threads on the pile reinforcement and using bolts to make the pull. but I am not sure how to design the threads and the bolts. Can anyone help?





RE: Tension Pile Load Test
add: How's about several cables at low tension each, since elongation is tied to stress.
RE: Tension Pile Load Test
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RE: Tension Pile Load Test
RE: Tension Pile Load Test
@PEinc, it is a 900mm diameter pile RCC pile, the depth of the pile is 20m. It is a single pile which is to be tested for a test load of 650 tons. the design is not ours. We are contractors who are asked to conduct the load test only.
@Retrograde, Yes, that is also one method of doing it. But unfortunately, the DYWIDAG threaded bars are not available here.
RE: Tension Pile Load Test
RE: Tension Pile Load Test
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RE: Tension Pile Load Test
Here's his linkedin page.
https://www.linkedin.com/in/william-f-bubba-knight...
f-d
ípapß gordo ainÆt no madre flaca!
RE: Tension Pile Load Test
Hire a pro to run the test. There is some danger here.
RE: Tension Pile Load Test
for a 20m length, prestressing strand extension should be in the order of 160mm. Multistrand jacks should have stroke of 200 - 300mm.
And you could anchor and grab again if you have to so that ytou can increase the stroke..
And this is assuming the strand is debonded so the force reaches the bottom of the pile. Does it need to or can the prestress tendon be bonded.
RE: Tension Pile Load Test
@PEinc, what do you mean by the mobilisation of the cone of soil? The stratum is dense sand up to 4m depth, followed by claystone of 2-5 MPa unconfined strength. I think the pile can take the load. I am thinking of prestressing strandwires for this test. I am only worried about the elongation.
@Fattdad, thanks for the contact.
@aeoliantexan, I guess 28 wiress would not be enough. The cross-sectional of a 12.7mm dia strandwires is 98.7mm2 and the breaking strength is 1.8MPa. So each wire would take 18 tons of load before breaking. that would be atleast 37 wires; more if we consider an FOS. End blocks, jack and wedges are available.
@rapt, The tendons would be bonded with the concrete. I am planning to insert two bunches of strandwires, 25 wires each. It would be embedded to 10m into the pile.
RE: Tension Pile Load Test
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RE: Tension Pile Load Test
2. 1,300 kips is very high. High powered math: ignoring top 5', then eff sidewall = 60' with diameter = 3.0'. fs = 1,300 kips / 565 sq ft = 2.3 ksf, if perfectly and uniformly resisted (it isn't).
3. I'm betting a cheeseburger that the load doesn't hold, but am happy to be wrong. I would really like to see the load frame and test results.
RE: Tension Pile Load Test
www.PeirceEngineering.com
RE: Tension Pile Load Test
You can get 15.7 - 15.9mm strand which takes about 300KN ultimate, so you could go to about 240KN per strand. Any reasonable PT company should be able to supply that. Some have jacks etc for 19mm strand if you want. We used that many years ago for pile tests.
Agree with the comment above about hiring a PT company that knows what it is doing to do the tests.
RE: Tension Pile Load Test