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Aluminum Pipe Piles

Aluminum Pipe Piles

Aluminum Pipe Piles

(OP)
I am working on the design/ specifications for a residential dock located in the Florida Keys (Coastal saltwater) The design calls for piles driven through sand/mud to rock approx 20-25' below water line with 9' above allowing for bents/stringers at 5'-0 AMHWL and 4'-0 projecting above decking. The total pile lengths will run 30-35'O.A. The design load for each pile will be 600lbs (bearing) (have not considered uplift at this time). A dock/pile contractor mentioned using Aluminum Tubing. Saying he has done it before with 3 1/2 OD x 1/4" wall and sleeved the exposed pipe w/ pvc post covers and caps. I like the corrosion resistance and it may look nice but I have structural concerns. I have spec'd the use of Steel pipe with closed ends, filling with grout, but never Aluminum. I cannot find much if any info on the use of aluminum piles, My Supplier has Schedule 40 6061 T-6 in 20' lengths. Has anyone seen Aluminum pipe piles? They will be driven with a 80lb pneumatic hammer w/ a cap type head (same one we use on steel) Rigging a barge in this location would be difficult. My main concern is bending during the driving phase and lateral load after install from shifting sediment etc. Any advice would be appreciated. (my first post hope I did not get to wordy) Thanks

RE: Aluminum Pipe Piles

Bad idea! The abrasion will remove the initial oxidation from the aluminum and corrosion will result. If you hit hard material (yes, Florida has some hard materials) you will likely do as you suspected...damage the pipe. In that area, you might also run into Oolitic limestone or coral, both of which can damage a "soft" aluminum.

You certainly don't want to grout the aluminum pipe....bad combination.

Stick with the steel or use wood.

RE: Aluminum Pipe Piles

(OP)
Thanks Ron, I had my reservations. Looks like that contractor does not know what he is doing. I am going to keep the 10" tapered wood pile spec w/ a schedule 40 steel pipe alternate that I have used before and forget about Aluminum. My guess is the "H" beam aluminum piles on elevator lifts the boat lift companies use does not get the scouring/abrasion since they are very close to the seawall. That was the only reason I thought Alum. pipe may work. No wonder I could not find any info.
Thanks Again
Rick

RE: Aluminum Pipe Piles

Ron didn't tell you that in Florida the Keys are not aluminum either.

Mike McCann
MMC Engineering

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