Pond Boss Forums POND CONSTRUCTION Selecting a site ConcertsePilings

I'd planned to pore Pilings for a bridge using concrete cardboard tubes. I hit water at about twelve inches below the surface. Do I use quickcrete without water until it fills and then fill the rest of the tube with concrete mix, or do I let the concrete harden up to surface level and then later pore the concrete/water mix on top? I need help!

Hmmm...more input, please.
How did you manage to cut the holes? I mean, I assume that you bored the holes with some sort of augur...right? How far below the level of the ground water do you have to go to hit firm, undisturbed soil? Is the soil so firm that the hole is not collapsing?...this would be a blessing.
I personally don't know the professional answer, but I do know that the best concrete pour is a continuous pour. I guess my first reaction is if you are able to bore to a firm soil footing, the hole doesn't collapse, and you have a foot or two of water within this hole, I'm thinking that the best approach would be to have a pump on hand to suck out as much water as possible moments before you dump in the concrete...one pier at a time. The concrete mix will displace any remaining water in the bottom, but it would be adviseable to have enough prepared to get above the water level in one shot (ie; a concrete truck). If you use a truck, they can control the mix to keep it on the dry side. I would also consider some small rebar cages.
-
All that being said, I am not an expert on this one. I would be doing the same thing; asking. I have very good contacts at my end with the concrete industry. If none of the PB'ers has true, practical experience to get your answer, I can get it later on this week.

The bridge is small, just 6 ft x 16 ft. It will span a culvert drainage inlet that feeds the pond. I'm digging four holes (maybe 6 to accommodate a middle support beam) by hand with a clamshell post hole digger and I have 8 in diameter cardboard tubes. I am close enough to the pond that I hit water about 1 ft below ground. I can dig the mud out of the hole to a total depth of about 32 inches. The base of the hole seems relatively solid. I had thought I might drive rebar into the holes as deep as possible before pouring.

I think you can pull this one off. A small hole like that fills up with concrete fast. I definitely like the rebar idea. I would have my wet/dry vac out there, mix a double batch of sakrete in the wheelbarrow (or plastic mix tub), suck out the water and po' in da 'crete.

Thanks Brettski. Pond Boss comes through again. Problem solved in no time flat!

i have poured concrete in tubes that had 3feet of water crete goes in water comes out [light poles] the only wrong thing that happen was i poured in the wrong place

Just was gonna echo mtb...I've poured sonotubes that were nearly submerged. Crete's heavy enough to displace the water. Dry mix...not a problem. Way easy with a concrete pumper, but not too bad with a ready-mix truck. Never tried it with sakrete, but mix plenty up at once...dump away.

Matt, this may be a dumb question but when you say "dry mix" are you referring to filling the Sonotube with dry concrete mix without mixing it with water?

I've done that before when setting some fence posts and relying on ground water to harden the concrete as time goes by. Would that work with filling Sonotubes?

Rob

Sorry Rob...not "dry" as in unmixed, just mix it on the dry side. It'll hang together, sink to the bottom and force out the water. Never tried dumping it completely dry, but I'd be concerned that it would separate out due to varying particle size...you wouldn't have "concrete" in the tube, but just layers of stone, sand and cement.

I've also dumped completely dry sakrete around posts (and my bridge piers) and it works quite well. Just try removing them later...that's different than having standing water in the hole.

Matt, I've seen dry cement dumped into water-filled holes, and it works great. I suppose it could settle out if the hole were very deep, but I can tell you from experience it won't separate in a 10 foot hole.

I'll have to remember that trick...saves some spinal wear...and I ain't got much "wear" left in me..

I am debating whether to use pressure treated 6x6's for my dock pilings sunk 3 feet into the pond bottom or use 4 foot Sonotubes for a base for the dock pilings. If I used Sonotubes and could just dump bags of dry Sakrete in them it would be real easy to do. However, I am not so sure the result would be strong/stable enough - or would it? I would also consider using this technique for pilings to make a bridge crossing over small creek.

I'd be somewhat concerned about dumping dry sackrete into a sonotube and expecting it to cure evenly and completely. After all, when I use it on posts, it's exposed to soil from all sides...allows moisture in.

Sonotubes are wax-coated to avoid immediate deterioration from the moisture of the concrete...and keep moisture from the ground out. They don't last forever, but even exposed to weather above-ground, they are in place for months (even longer, sometimes).

If it was me, I'd use ready mix (already wetted) inside a Sonotube. Just MHO...

Not sure what your looking for, water after cure is the best, dumping concrete freely into water, not good.

Well, I finally finished my bridge. It is nothing like the extravagant "cantilevered, reticulated, bifercated" construction gems of fellow members, but I'm happy with how it turned out. Incidentally, we've had very little rain this summer. When the pond is full, the water will be within several inches of the bottom beam. On to the next project!

It may not be "cantilevered, reticulated, (or) bifercated", Schroeder, but it's shore purty and looks like it'll hold up anything that might want to walk across it.

Yep...a spanningly attractive pc of woodworking. Nice job, Schroeder.
-
how 'bout a shot from behind it, looking out toward the pond.

I like that. May not be extravagant as you pointed out but it is attractive and functional. I have a similar project on my to-do-list. I may not get to it for quite a while but I'll certainly remember how you made your bridge.

Brettski - My pond is so overgrown with weeds, Id be embarassed to show a photo from the other direction. As it was, I raked the algae from under the bridge area before I took this photo. I thought I'd go chemical free this year but the results were disasterous. Back to chemicals next spring!

That looks really nice Schroeder. Well done!

That is one nice bridge and its even on pilings.

Nice looking bridge Schroeder. Ole fish bain here made the mistake of showing it to my wife. I'll either have to build one, or make up something, like "Our soil is incompatible with concrete pilings".

Great idea! I think you did a good job. We need something similar that we can take the riding mower across. I'll add this to my favorites, for my 'honey I want this' file.

Anyone care to estimate what Schroeder's bridge will safely hold? I'm looking to build a similarly sized bridge for people, ATV or a horse/rider - not a truck or tractor. I've asked a similar question on other websites but the answer always seems to include engineering tables

Give it your best estimate - don't worry, I'm not a lawyer.

If it weren't mine, I wouldn't hesitate to take a 1/2 ton over it.

Horse and rider, might go 1500 lbs - double the length-wise beams and use 2"x4"s for decking, set with the 1.5" edge horizontal and the 3.5" edge vertical. That ought to double the capacity and handle a heavy point source like a hoof.

P.S. I'd feel better about it if the ends of the beams didn't taper as much.