Partial depth pile reinforcement
Partial depth pile reinforcement
(OP)
Recently, a project at the office only reinforced the top 20' of some cast in place friction piles. This helped a lot with installation, it was a small project so schedule was tight. My thinking is the piles can be designed such that all flexure and upflift is taken by the upper portion of the pile, leaving the unreinforced portion to act only in bearing. I can't really find any sources to back me up, foundation books don't mention reinforcing and concrete books don't really mention piles. Any thoughts?






RE: Partial depth pile reinforcement
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: Partial depth pile reinforcement
My bet (I may have ran this number a few times before ;D) is that once you start accounting for pile dead load, over and above the dead load on the pile already, at about 20' you'll find that concrete tensile resistance is enough.
RE: Partial depth pile reinforcement
RE: Partial depth pile reinforcement
RE: Partial depth pile reinforcement
I don't believe that either of these approaches would prevent tensile cracking of a pile in uplift. Developing shaft skin friction in uplift requires some upwards displacement of the pile. For that upwards pile displacement to not crack the pile, the un-reinforced length of pile and any soil engaged by it would have to come along for the ride. In reality, I don't think that there is a zero tension point in an uncracked, uplifted 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: Partial depth pile reinforcement
RE: Partial depth pile reinforcement
http://www.soilstructure.com/
RE: Partial depth pile reinforcement
RE: Partial depth pile reinforcement
RE: Partial depth pile reinforcement
RE: Partial depth pile reinforcement
The issue with belling for uplift is there's always some reason the contractor can't do it, i.e. sloughing of the bell, boulders, high water etc.