Effect of coating on Steel Piles
Effect of coating on Steel Piles
(OP)
I'd like to inquire if anyone can advise on whether the external coating on steel piles would have an effect
on the skin friction and the performance of the pile.
In this case the production steel piles may be galvanized or epoxy coated. Would pile tests using uncoated
steel have a material effect on the test results?
My preference is to use test piles identical to production piles. However, this question has come up in order to try
to expedite the pile testing.
on the skin friction and the performance of the pile.
In this case the production steel piles may be galvanized or epoxy coated. Would pile tests using uncoated
steel have a material effect on the test results?
My preference is to use test piles identical to production piles. However, this question has come up in order to try
to expedite the pile testing.





RE: Effect of coating on Steel Piles
layers of sand or loose sand.
Some of the steel piles will be helical piles which are sensitive to the installation torque. It seems possible the increased friction of bare steel against the clay would have an effect on the installation torque.
RE: Effect of coating on Steel Piles
Never Galvanize Steel Pile
Dealing with Piling Corrosion
In Ground Performance of Galvanized Steel
All of the above deal primarily with the corrosion aspect of the piling - not the skin-friction aspect.
Texas DOT recommendations for coatings:
https://ftp.dot.state.tx.us/pub/txdot-info/brg/geo...
It seems that a big concern is that as you drive the piling, some of an applied epoxy, or other coating might come off and this creates an accelerated corrosion potential in the pile...more so than if it was uncoated.
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RE: Effect of coating on Steel Piles
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RE: Effect of coating on Steel Piles
RE: Effect of coating on Steel Piles
Other piles will be driven steel round HSS
RE: Effect of coating on Steel Piles
Since the pile capacity of helical piles can be correlated to the installation torque, I think it would be essential for indicator/test piles to be the same as production piles. A lower energy surface blade should reduce drag as the blades of the helical pile shear through cohesive soil.
RE: Effect of coating on Steel Piles
For epoxy... abrasion during driving would probably make it ineffective as corrosion protection. Since the epoxy would likely be "gone", I suppose the affect on skin friction would be minimal. But if epoxy is no longer present, no point in using it.
With steel H-pile, one anti-corrosion step is to specify (A36) steel with increased copper content (or to just use an available higher corrosion resistant steel alloy). Extra copper helps... a little. With HSS, probably not an option for either method.
For steel piling that extend above the ground line, one technique is to dig down a short distance after driving and paint the pile with bitumastic for a couple of feet both below and above the ground line. This is the where the worst corrosion is likely. With an HSS, could not get the bitumastic to the inside surface.
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RE: Effect of coating on Steel Piles
My understanding is FBE will be more resistant to removal by abrasion during driving or, in the case of helical piles, during installation.
RE: Effect of coating on Steel Piles
With all due respect to JAE - whose opinion should be heavily weighted - I must take exception to one of the attachments.
The first article from APE regarding HD galv on helical piles makes a few questionable claims, and should be compared with other data and technical opinions on the matter arguing to the contrary.
Otherwise, the other links are good.
Back on track now.
Pile friction has wide scatter, even when controlling for all the variables (as if that's possible with geo-structural). The persuasion to match test piles with production piles is prudent.
RE: Effect of coating on Steel Piles
I guess to some extent pile installation is monitored during the hammering and isn't the actual in-place capacity of the pile determined by blow counts, dynamic monitoring, etc.? So the effect of any coating would simply be reflected in the on-site results correct? Need some geotechnical folks to weigh in.
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RE: Effect of coating on Steel Piles
Friction driven piling "set" after driving has been completed. Typically takes overnight, or so. Load capacity is increased after "set" when compared to load capacity immediately upon completion of driving. That's why a load test (performed well after driving of the test pile and reaction piles) is sometimes used to calibrate blow count and PDA results.
To extract friction piling, Contractors can break "set" by driving the pile down a few inches before extraction. Handy for removing the reaction piles.
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RE: Effect of coating on Steel Piles
RE: Effect of coating on Steel Piles
Dik