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  1. #1

    Piling extensions over or under engineered

    The existing pilings are not as tall as Lilly Marie's sheer of the boats at high tide. Wanting to add 3 feet to the existing piling height, we cut a 3 ft piece off of the butt end of a scrap piling then drilled 4 holes into the top of the existing piling and the 4 holes into the end of the scrap piece, then filled all 8 holes with thickened epoxy resin and inserted 5/8 x 16 inch rebar into the holes on one end, added more thickened epoxy to the top of the piling then put the 3 ft piece on top.

    Problem is the holes and rebar are difficlut to line up even with the jig. We had difficulty with the first one and almost did not get it to come together. I would like to use one pair of holes and one piece of rebar per piling, located in the center of the piling. That would be much easier alignment, I wonder if one rebar provides enough strength?

    An Internet site indicate that 5/8 rebar epoxied into concrete has a tensile strength of about 24,000 pounds. My shade tree engineering tells me that a 3 foot lever against an 8" piling base (4") radius against a length of rebar at center would be a 9 / 1 reduction ( 36" / 4" = 9) Thus the joint should stand a 2,666 lb pull to the side from the top of the piling.

    Any thoughts on this?
    Attached Images
    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    “Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. ... To be "cured" against one's will . . . is to be. . . classed with infants, imbeciles, and domestic animals.” C.S. Lewis, God in the Dock

  2. #2

    Re: Piling extensions over or under engineered

    Have you thought about sleeving it with a steel pipe over the existing piling? You would only be increasing the OD of the piling by the wall thickness of the pipe.

  3. #3

    Re: Piling extensions over or under engineered

    Sleeving the piling is a great idea!

  4. #4

    Re: Piling extensions over or under engineered

    Thanks,
    I had not thought about sleeving it with steel pipe, sounds like an effective solution if I can put my hands on 8 to 11 diameter (the pilings' diameter varies) steel pipe that can be cut in 12-18 inch lengths. Any suggestions on where to find this without going overboard on cost?

    I have been thinking about wrapping the joint with fibergalss cloth tape and epoxy, and could put some steel tabs underneath with screws through the tabs and into the pilings.

    There are probably a lot of ways to increase the strength of the joint, but how much is enough. That's the engineering component of this post.
    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    “Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. ... To be "cured" against one's will . . . is to be. . . classed with infants, imbeciles, and domestic animals.” C.S. Lewis, God in the Dock

  5. #5

    Re: Piling extensions over or under engineered

    You could put a steel pipe over those pilings long enough to sit on the sea bottom. Because you only need a 3' extension I would buy large PVC pipe, cut them to a length that would allow the PVC to sit on the bottom and extend 3' over the existing pilings. I would also glue a PVC cap over the top. Those tubes should be cheaper than steel, have adequate strength, and with the nice caps, should look a lot better than rusty steel. We do that trick in the Great Lakes over small diven steel pilings to avoid damage to a boat. Over steel pilings the PVC will actually roll as a boat slides its rubrail along the piling.
    Maynard
    UNITY '86 36C

  6. #6

    Re: Piling extensions over or under engineered

    Like Maynard suggested, you can sleeve them with PVC no matter what you use for the structural part of the extension. This way you could still do your fiberglass joint or some steel tabs or a steel sleeve or whatever. It won't matter how is looks because the PVC will finish it off nicely.
    Sky Cheney
    1985 53EDMY "Rebecca"
    ELYC on White Lake--Montague, MI

  7. #7

    Re: Piling extensions over or under engineered

    Thanks,
    The idea of a PVC sleeve sounds like an excellent solution to put over the wood extension with one rebar dowel.
    Regards,
    Vincent Castigliola
    Lilly Marie - 43 DC 1983
    Pascagoula, Mississippi

    “Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. ... To be "cured" against one's will . . . is to be. . . classed with infants, imbeciles, and domestic animals.” C.S. Lewis, God in the Dock

  8. #8

    Re: Piling extensions over or under engineered

    All I did was bolt a 3 X 12 to the inside of the piling. you can sink the bolts into the wood so they dont scratch your rub rail. so easy, even a caveman can do it

  9. Re: Piling extensions over or under engineered

    I assume George means "outside" the piling....anyway, that's what I was thinking....
    I'd place a pair of heavy such wooden pieces perpendicular to the hull, for added strength, and thru bolt the pieces...two bolts on top two on the bottom. If you have the beam room, you could also bolt a single thicker piece of womanized lumber directly to the existing pile to extend it.....that would also serve to keep the hull and fenders off the creosote soaked piling....
    Rob Brueckner
    former 1972 48ft YF, 'Lazy Days'
    Boating isn't a matter of life and death: it's more important than that.

  10. #10

    Re: Piling extensions over or under engineered

    Quote Originally Posted by REBrueckner View Post
    you could also bolt a single thicker piece of womanized lumber directly to the existing pile .
    So does womanized lumber come from this kind of a tree?

    Sky Cheney
    1985 53EDMY "Rebecca"
    ELYC on White Lake--Montague, MI

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