Axial Load capacity for an partiall encased pile
Axial Load capacity for an partiall encased pile
(OP)
Hi,
I have an HP pile in the water, 29 feet exposed height and assuming fixity at 20 feet below mud line.http://www.eng-tips.com/
The pile is encased by 24" diameter concrete from top until 15 feet down (almost half the exposed height is encased)
How to calculate axial load? How to calculate the P critical for buckling.
I appreciate if sample calculation or spreadsheet is available..
Thanks
I have an HP pile in the water, 29 feet exposed height and assuming fixity at 20 feet below mud line.http://www.eng-tips.com/
The pile is encased by 24" diameter concrete from top until 15 feet down (almost half the exposed height is encased)
How to calculate axial load? How to calculate the P critical for buckling.
I appreciate if sample calculation or spreadsheet is available..
Thanks






RE: Axial Load capacity for an partiall encased pile
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Axial Load capacity for an partiall encased pile
Make sure that you're adequately accounting for any cracking in the concrete section.
RE: Axial Load capacity for an partiall encased pile
Can I reasonably assume the same with the following 2 scenarios:
- the same 49' long HP with 30' encasement (~full of the exposed height and 60% of the total height)
- 35' long HP at shallower areas (15' exposed + 20' to fixity) with 15' encasement (full of the exposed height ~ 50% of the pile)
Thanks
RE: Axial Load capacity for an partiall encased pile
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Axial Load capacity for an partiall encased pile
It's usually a relatively easy thing to do and it either gives you a load factor by which you can increase the loads, of it gives you an effective length factor so you can go off and design it. It's usual practice to decrease this by a factor of say 0.8 so it's consistent with code values as the code length factors have some conservatism when compared to the exact Euler buckling length factor. For example a fixed/fixed ended column is potentially taken as 0.7 in a code, but the true Euler solution is 0.5 for the same scenario. This difference usually accounts for imperfections, for example initial variations in the straightness for the members.
RE: Axial Load capacity for an partiall encased pile
The key to getting an accurate answer is how "good" is that assumption (especially at the pile's full loading). Soils must be "poor" to have fixity that deep. Assuming a point of fixity is reasonable for piles with conservative loading (and generous safety factors). Since the intent is to maximize loading based on pile buckling, IMHO, assigning an estimated depth to full load fixity is not wise.
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