Concrete for grain bin pad?

I just bought a 24 ft. 6000 bu grain bin and need to pour a pad for it.How thick should it be and how far in the ground? How much rebar should I use as well? The bin will have a drying floor and I am located in southern WI.I was thinking of a 25 ft round pad. Thanks Tom

I would definitely pour a square slab with copious amounts of rebar. It is the best way. If you do it any other way your life will be a living he11.

I ask the Wheat Baron. He just did one.

If the pad area is on very sound footing a square pad is acceptable,otherwise round is the only way to go. Have seen pad corners cut off when bin settled on ground that was unstable. Have a 32 foot
21k bu. bin and 7k bu. bin on 6 inches of mesh
reinforced 4k concrete on 30 inch stone base. Base
necessary to bring bins level to adjacent building.

For a grain bin that size I would want a slightly bigger pad than 25 feet. The base angle will be around 1 1/2-2", then you add a few inches for where the loops for hold downs go, then a few more inches for a margin of safety. I would want some more room than that. As far as thickness on bins that size I always used at least 6" thick and at least a foot or more deep on the footer (beyond the ground level), which would be about a foot wide as well. Some well compacted fill under the center is important as well. I like a 12" form for a grain bin that size. At the size bin you have I assume it is 1around 16-18 feet tall. A floating pad will work just fine. You will also want to consider an adjacent pad for a fan if you want to aerate the grain. Mike

Been around hundreds of steel bins and never even seen one with s square pad. I don't understand.

I have a great deal of experience in the matter as well as exceptional skidder skills. Square is the way to go with lots of rebar.

Exactly, but I would add 1/2" Re-bar to both the bottom AND top mesh.

Mesh, all by itself is not much re-enforcement..

Ron.

Well tom,
First thing is to box out a suitabe level area, with no organic matter remaining. Then compact it well with a plate tamper, the motor driven type, and then put down a 6" layer of crushed gravel/stone, and compact that well.
Then lay down a 6mil. layer of plastic, which will prevent moisture migration from the bottom. trim the outer edges so you don"t form a sauser. Put in 6" forms, with a couple of rings of #4 bar around the perimiter. Then fit in 6" square mesh in the center field setting on small peices of broken padio blocks to hold it up into the pour.
You should be good to go. After cured, apply your mastic seal, drill crete, and drive "Reds" in and tighten down.
Loren, the Acg.

You are right I do want bigger than 25 ft. Do I need to pour a footer then set my forms or can it all be done in one pour?

You may want to dig a haunh around the outer periniter, 12-16" and fill with concrete and an additional course of rebar down near bottom if you are in an area with poor drainage. Use 4000# mix, fiber optional.
Loren, the Acg.

Make sure you are high enough off the ground so your truck auger will go under the bin auger. You'll have to figure that out yourself because I don't know what your auger situation is. Figure enough room under the bin auger for a short spout hanging down under the auger. When I was trucking grain for other farmers that was the most prevalent problem we had. If the auger is too low you will have to chip frost to get the truck auger under. Then the snow will thaw a bit and ice will fill the hole you just got sore muscles from chipping out. The other guys know a lot more about laying out the pad than I do so I can't help there.

I think you should go atleast 26' and we just put sand down and poured the crete over it. If you are putting a drying floor the unload tube will come out though under the floor. If you a 45 degree unload, the pad can be just above ground level. If you want to unload straight out into an auger, you will want to have your pad around 24" above ground or you will have to dig a hole to spot your auger. Pour you aireation pad for the fan at the same time. The last crete I poured, I used fiber in it and has worked well so far. Use new bolts in you bin even though it is a small one.

Never seen a square bin pad.

Around my neck of the woods they pour what they call a floating footer. Bout a foot half to two foot thick and deep around the outside.

If it's a new bin, the bin manufacturer probably has some specs. They did for me.

Put up a new 30' 9 ring last summer- I think the footing was 31'6'' or 32'. Concrete side wall was 2 ft high, 6" deep in the middle. Used rebar throughout the floor, but most important, 2 rings of rebar inside the edge of the wall. Inner and outer rebar rings were spaced so as not to interfere with bin anchor bolts.

I probably have the spec sheet somewhere.

I don't see the advantage of a square pad for a round bin, then you are not on the footing with the bin wall so ots weak, and you are pouring a lot of concrete to the corners that doesn't get used, in the way, wasted material and wasted space.

Don't ever see that, seems out of step?

Paul

Many good ideas and they probably will all work. I have seen square grain bin pads, but they are not common. If you are pouring the pad yourself use the 7/16" masonite 12" lap siding for the form which is available reasonably at all lumber yards. You may know someone who has the steel grain bin forms, but I have built three grain bin pads with the masonite siding and it works well as it bends to make a perfect circle. I think your diameter was 24 feet. So, you would want a minimum of 6" to as much as 8" beyond the grain bin all around the outside. So, you are looking at 25' to 25' 4". To be on the safe side and depending on the type of hold downs you have maybe 25' 6". Strip the sod and fill with something that won't settle if fill is needed. Waste lime, gravel fines, etc. are fairly cheap and pack well. Spread in layers and pack each layer. I packed with a tractor. When the base is completed find the center and drive a stake. 1" to 1 1/2" water pipe works good for the stake. Tie some heavy cord around the pipe and 25' 6" out from the center tie the cord to a piece of 1/2 rod. Holding the rod straight up and down while keeping the line tight scratch a mark in the fill. Make sure the cord doesn't wrap on the center pipe. You can also use some 2 by 4's nailed together with one spike near the end centered in the water pipe and another big nail at the 25' 6" distance. Use the big nail at the end to scribe a line. Either way the line becomes the inside of the forms. Cut some 1 by 4's into 24" stakes with points at one end. Drive these stakes 7/16" outside of the line you marked in the fill. One every foot and a half driven 12" into the fill. Now dig a trench 1 foot wide and 6" deep into the fill. This will give you an outside wall one foot wide and one foot deep. Make sure the top of the center pipe is 6" above the fill. Run a screed board from the pipe to the tops of the stakes making sure each stake is level with the center pipe. When the stakes are driven and level with the center pipe attach the masonite siding to the inside of the stakes with nails bending and pulling the siding up to the top of the stakes. On the first stake center the siding 1/2 way so when you finish the last piece of siding has something to attach to. You have to start at one end nailing so using some "shims" under the siding towards the loose end helps everything fit and be level. At the very end you might have to cut the siding to fit. Verify that the 1) form is level with the center stake all around the outside, 2) that you have 6" between the bottom of the screen board and the fill, and 3) that you have a one foot wide trench which is one foot deep around the outside. Using some cable or log chains go around the outside and pull it together with a come-a-long. Make sure the cable is about 1/2 to 2/3 the way up. The cable makes it so the forms can handle the pressure. Lastly the re-rod. I think this is based off of Conrad America recommendations. Two re-rods around the outside in the trench. Both four to five inches in from the outside of the form. One four to five inches from the bottom of the trench and one four inches down from the top of the concrete. Drive vertical pieces of re-rod in the trench to wire tie to. Lastly, re-rod north and south every 2 feet and re-rod east and west every two feet. All tied together with wire and sat on pieces of rock or brick midway up into the 6" floor. Forming is the hard work. I used a garden tiller to help cut the outside trench. I was told plastic under the concrete is not needed if there is an air floor in the bin. Grain on concrete - yes. I did put plastic under the ones I have built even with floors. A couple bins I put the hooks into the concrete while wet. The last one I used the expanding lag bolts after the concrete had hardened. The trench is necessary to support the weight and to keep rats out. The bigger the bin the deeper and wider the trench. I believe the one foot by one foot works for bins up to 27 feet. Even on the 18 foot diameter bins I have used the 1' by 1' trench. If you already have a level and firm site you could set the 12" masonite forms on top of the ground and then fill the inside with good fill leaving the 1' by 1' trench and 6" for the floor. There are alot of ways, just sharing mine. Bin crew would probably charge at least 2 times the concrete bill for a complete job especially with all of the re-rod. Good luck.

(quoted from post at 16:21:21 06/25/14) I have a great deal of experience in the matter as well as exceptional skidder skills. Square is the way to go with lots of rebar.

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Could you post a link to a video that shows your skidder skills?

Very detailed instructions, just the way I would do it!