Closed End Pipe Piles w/ Concrete Fill @ Top End Only
Closed End Pipe Piles w/ Concrete Fill @ Top End Only
(OP)
My client is driving 100' long, closed end, pipe piles, approx. 24" diameter for a wharf. The plans call for the upper portion (about 20') of the pile to be concreted. Does anyone have any good reasons why or why shou;dn't the pile should be totally dewatered inside and below the concrete plug? If the pile is dewatered inside, there will be a very high water pressure on the outside of the pile. If the pile is allowed to have water in it below the concrete plug, the unbalanced water pressure on the outside of the pile will be minimal.
Any thoughts, warnings, known problems?
Any thoughts, warnings, known problems?





RE: Closed End Pipe Piles w/ Concrete Fill @ Top End Only
RE: Closed End Pipe Piles w/ Concrete Fill @ Top End Only
RE: Closed End Pipe Piles w/ Concrete Fill @ Top End Only
RE: Closed End Pipe Piles w/ Concrete Fill @ Top End Only
RE: Closed End Pipe Piles w/ Concrete Fill @ Top End Only
I designed a L-I-P form for the concrete on a similar project for the same client. The form will hang from the top of the pipe pile. Because the pipe is closed end, the contractor will be able to dewater to a little below the bottom of concrete plug. Then, there should be little or no air inside the pile. The water in Port of Wilmington, DE should be fresh water. Occasionally, the salt line advances to Wilmington, but not often.
On Page 372 of Tomlinson's 4th Edition of Pile Design and Construction Practice, it says, Where hollow steel piles are plugged at their base with concrete or impervious soil it issometimes the practice to pump out the sea water and replace it with fresh water containing a corrosion-inhibiting compound. The addition of sodium nitrite and sodium carbonate to form a 2% solution can be used for this purpose. However, the need for this has been questioned because an empty or sea water filled pile contains little oxygen which is quickly used up in the early corrosion process, leaving none to maintain the corrosion." Any comments or disagreements?