Thursday, December 1, 2016

Steel Grain Bins: Construction

(Update: steel bins sometimes do collapse.)

I came across the following video on Facebook. Unfortunately, they don't mention how many bushels this bin can hold nor does their website.

They do provide a video that shows how the pad is built. I was surprised they didn't install an auger in the pad so that you can unload the bin from the center. This video shows a concrete pump in action.

Pouring an 82' pad  for a 78 foot bin. It says 200 bushel. It must mean 200k bushel. Again, it appears there is no auger from a central hole. That rules out being able to use a "sweep auger" to empty the bin.

I was hoping to find a list of bin sizes that Wall Grain sells. But they want me to contact their sales representative instead. That is not going to happen. They do make at least 108' diameter bins.

"How Farms Work" has a series of videos on the building of their 20k bushel bin. For example, building the roof. ("How Farms Work" is one of two farm channels I follow. "The Farming Life" is the other channel. When I did a search for the channel name, I happened to find a "tour" video, which was of interest to me. I do skip the tobacco farming videos.)

Sukup does provide dimensional data and bushel capacity. Evidently ASCE7-05 Code is a standard for bin designs and it specifies a snow load of 40 psf (pounds per square foot, I presume) and 90 mph winds. They distinguish between Farm Bins and Commercial Bins. Farm Bins are smaller and are designed to handle additional forces caused by drying (heated air circulation) and stirring the grain. Commercial Bins are designed to just store grain. Their biggest Farm Bin is 48' in diameter and 58'9" high with a max capacity of 73,711 bushels. Their biggest Commercial Bin is 156' in diameter and 123'3" high with a bushel capacity of 1,522,863. They also have Hopper Bins, but farmers use those for supplements rather than for bulk grain storage.

GSI characterizes its product line in terms of construction technique.
Sioux Steel has farm (max 48x37 or 60,690bu), farm/commercial (max 66x51 or 174,656bu), and commercial (max 132x77 or 1,022,336bu).

Sioux Commercial Features
Sioux makes a big deal about grain weights increasing "due to new hybrids and genetics. An average of 60 lb. per bushel corn, 60 lb. per bushel wheat and soybeans range in the 55 lb. to 60 lb. range." They have a 64lb/bu series and a new 70lb/bu series. [Sioux]

Brock also distinguishes between farm (max 54x30 or 65,879bu) and commercial. They have three series of commercial bins, of which the M series seems to have the biggest bin (max 156x70 or 1,338,574bu).

A formula for converting from dimensions to bushels is BU = 0.6288*D^2*H. [cropwatch] The actual figure is higher because that formula assumes the top of the grain pile is level. For a more accurate computation that includes the peak you have to specify the type of grain and its moisture content: bin calculator.

Of course, capacity doesn't mean anything until you see cost figures.

It turns out this video is a compilation of "farm equipment fails." But this was the "click bate" picture and I though it was a neat demonstration of the strength of steel bins. I assume it is full and that is where much of the strength comes from. This is also a good demonstration that when you are backing up, you should be looking backwards!

While studying covered hoppers for grain hauling, I learned that wheat is heavier than corn. "Wheat tares out and cubes out in a 4750 cube, 286K Trinity car, whereas corn tares out and cubes out in a 5161 cube, 286K Trinity car. There are some 4750 cube 286K Trinity cars out there in the fleets, but they're a definite minority." [Trains20090310, msg Railway Man] The industry switched to the bigger cars for standardization and only partially fills them when carrying wheat.

The steel bin collapses even though it was only partially full. The article says "elevator" when it should say "bin." I wonder if this was "first fill." I also wonder how windy it was at the time of the collapse.

35,000 tons is 1.25 million bushels of corn.

The Farmer's Life posted three photos of the construction of a new bin with the comment:
Bin progress. A few more rings taller on this one yet. Third pic is the jacks inside that lift it to add the next ring. Bins are built from the top down and lifted as you go.
1, cropped


The Farmer's Life posted
Take two!
The Farmer's Life 22,000 each
The Farmer's Life The other bin will attach to that same platform at the top. Two bins, one stairs.
[First bin is done and they are starting the second one that he is building this year.[

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