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Re: prestressed piles

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you might consider to do a load test.
Chris Lillback

Roger Turk wrote:

> Acie,
>
> The prestressing in concrete piles is simply to facilitate handling them
> during transport.  Prestressed piles are typically precast and must be
> transported from the plant to the site, then moved from a horizontal position
> to a vertical position and driven.  Any driving force simply reduces the
> tension in the prestress strand.
>
> A side benefit of prestressed piles is that you *know* that the pile can take
> a load equal to the prestress force.  Therefor, if your final prestress
> force  is 240 kips plus a factor, then you know that the pile will take 240
> kips.  An old rule of thumb was that a vertical pile could resist a
> horizontal load equal to 2% of the pile capacity.  Battered piles were used
> to resist horizontal loads greater than 2%.
>
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona
>
> Acie Chance wrote:
>
> <<     I could use the help of anyone who has experience designing
> prestressed concrete piles. I need to design a 100 foot long pile to take 240
> kips of vertical load and 45 kips of horizontal load. The top 25 feet will be
> a composite pile,  30" diameter drilled pier with conventional reinforcing
> and the prestressed pile extending up through the composite length to the pile
> cap. The idea is to predrill the 30" section then drill a smaller hole for
> the remaining 75 feet. The prestressed pile will then be driven and a rebar
> cage lower around it for the first 25 feet. The soils engineer has given the
> 240 kip load for a 14" diameter pile. The top 25 feet will take the 45 kip
> horizontal load.
>      I have been reading about prestressed piles but the information I have is
>
> not  specific and none have any thing about a composite pile. As this project
> is to go for a review of the 100% package in three weeks time is important to
> me. Any help on references which include design examples of prestressed piles
> would be appreciative. Additionally any pitfalls on using pile splices would
> also be appreciated.<<
>
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