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Join Date: Dec 2020
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Concrete Boat Pier Deck

02/20/2021 8:35 PM

Hope to get some help. I have searched thru the forum and there is a lot of useful information. I have a pier on the coast of Louisiana and tired of having to rebuild and replace after a storm . I have currently set concrete pilings set in place at 10' center 48" wide. They were poured in forms and jetted in place. The piles are 5000# mix with a water reduction additive and fiber mesh with basalt epoxy re-bar to prevent corrosion failure . What I want to do is build the deck also out of concrete using the same mix. I would build each deck form on the ground then lift in place. The deck dimensions 46" wide 10' long 5 1/2" thick. I have #3 basalt re bar and would place 6 bars 7 1/2" center on the length 2" from the bottom of slab and 8 re bars across the width equally spaced to form the grid then add a second grid 2" above the first. This is a sketch of the pilings I have in place. they are jetted down 7.5' below the water bottom and I want to open span across each sry I can't turn picture. I know that each deck would weight approximately 2650# will this span the 10'

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#1

Re: Concrete Boat pier deck

02/20/2021 10:04 PM

That should be fine....but what is the placement of the supports in relation to the slabs?...and how high is the slab deck above the sea floor?

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#2
In reply to #1

Re: Concrete Boat pier deck

02/20/2021 10:48 PM

How is the deck secured to the pilings? Is the pier protruding out into the water or is it parallel to the shoreline? It isn't clear how all the pilings are of uniform length and if the shoreline is sloping down how can the depth that the piling are into the seafloor be uniform?

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#4
In reply to #2

Re: Concrete Boat pier deck

02/21/2021 7:36 PM

Thanks SolarEagle

The pier runs perpendicular to the land 400' out in the water . The bottom next to land is in about 14" of water and out at the 400' mark the water depth is 3-1/2 to 4' so the piles are jetted down to have at the top of cross member about 24" above the water at normal tide. Which gives the piles near the land jetted down about 9-10' and the ones near the far end are about 6-1/2' below the bottom if I remember correctly. To keep them level and straight we put temporary post out in the water the pulled a string line every 100'

As for securing I'm up in the air about that thinking about epoxy or maybe bolting 2, 2x6s sandwich to the top of the piling any suggestions. Also the last picture is one of the pilings after we pulled from form.

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#3

Re: Concrete Boat pier deck

02/20/2021 11:03 PM

I don't even need to do the math...you're good on design.

Hurricanes however.......hard to calculate.....

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#5
In reply to #3

Re: Concrete Boat pier deck

02/21/2021 8:32 PM

Thanks WJMFIRE you're right about the damn hurricanes I hope if the decks get lifted off the pilings they don't get to far or damaged and we will be able to pick them up and put them back. I was thinking of maybe redesign the deck to make them a little lighter . It would save about 500-530# but it may sacrifice strength. Look at the attachment and tell me whats your thoughts on this

It would only give 3" of thickness across the top. With the tunnels going the length of the deck 10.' Where the filled areas at 5.5" thick would act as the support system. I don't know if its worth the 500# saving in weight 2640# vs 2140# any suggestions appreicated

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#6
In reply to #5

Re: Concrete Boat pier deck

02/22/2021 8:49 AM

The waffle design should be fine...one thing working in your favor seems to me is that the water isn't that deep, so the forces are reduced, I mean even in a severe tidal surge the pier would likely be underwater....I would leave the deck unbonded to the supports and allow the expansion and contraction of the concrete to take place unfettered...I might consider some wedge concrete pieces that would fit the grooves underneath to provide some added support at the joints...maybe 4 ft pieces that I would bond to the supports...

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#8
In reply to #6

Re: Concrete Boat pier deck

02/22/2021 8:02 PM

Thanks SolarEagle

I will just let the decks sit on the supports. I did think about the expansion factor especially during the hot summer day we have down here

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#7

Re: Concrete Boat Pier Deck

02/22/2021 3:53 PM

Is it to be on the shore of a lake, or of the Gulf?

When completed, how long is the total pier length to be?

Is any vehicle, or equipment, or other heavy loading, to be transported along the pier?

Exactly how is the deck slabs to be anchored to the piers? and, to each other?

If there is a (surviving) pier still in the general vicinity, how was it designed, built, repaired, etc. ?

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#9
In reply to #7

Re: Concrete Boat Pier Deck

02/22/2021 8:11 PM

Hey Mr Guest

The total length is 400’ It is on the bay. Only foot traffic. Maybe a dolly to carry a couple of ice chest and fishing gear back and forth. The width of the pier will be 46”.

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#10

Re: Concrete Boat Pier Deck

02/22/2021 9:47 PM

Hello,

No comment on the strength, not my field.

For the ends though, you might like to consider "fingers" so that end of segment 1 is aligned into the start of segment 2 and so on. Like expansion joints in bridge decks. This would assure the alignment of segments doesn't crab sideways, but still have no rigid connection.

If you make vertical fingers, would needs a skid plate on one segment to cover the slots. Horizontal fingers would need protection of the top.

Maybe a more simple method would be like a horizontal mortise/tenon with tabs only at the slab edges.

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Ejpoche (4); Just an Engineer (1); MR. Guest (1); SolarEagle (3); WJMFIRE (1)

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