I have a 40ft steel shipping container on my land. I am wanting to attach it to some sort of anchor system to hold it down during a tornado.
I was thinking of taking an auger and drilling a 6 ft deep hole at an angle. Then filling in the hole with a car rim and then rebar. Then wrap a heavy gauge steel chain through the anchor points on the shipping container and through the rebar and the rim. Then fill the hole with high strength concrete.
Let me know if you think my idea would hold up against high winds from a tornado. Or if you know of some better ideas on how to anchor the shipping container down let me know!
I appreciate any help, thank you!
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posted 7 years ago
Like your idea for a container in the woods. Have ya tried checking with a mobile home business, they 'set up' and 'tie down' mobile homes all the time. My mobile home has steel stakes (driven in the ground at an angle) and steel straping is looped around the main frame and back to the anchor bolt. The anchor bolt is fixed in a yoke atop the steel stake, the anchor bolt has a slot in it, and both ends of the steel strap go thru the slot, the anchor bolt is then turned with a wrench till the steel strap is tight, then the anchor bolt nut is tightened to secure the adjustment. There are (4) of these total on the mobile home.
My steel frame carport is anchored with simple 3' lengths of unpainted rebar 3/4", a nut is welded to the top (to make a nail head) and the rebar is pounded 3' straight thru the carport frame, (if the predrilled holes in frame where at an angle, I guess the rebar would drive in at an angle) into the rocky clay. There are (6) rebar used total on the carport.
I feel pretty good with both these securements, have seen some earthquake & tornado type weather many times.
The hard part is: driving a rebar 3' or more deep ~~it was all I could do to get it 3' deep, the rebar will break thru sandstone as you keep pounding (sharpen the tip like a nail), but other rocks probably not. Also 3/4" rebar is like a bent nail, and if you bend it wrong while beating it in, it is very difficult to drive it much deeper once it has been kinked. You might use 1" rebar. I'm thinking those locking holes on the corners of the container, maybe you can just drive a rebar thru the frame there at an angle, or drive a rebar thru a short length of chain, then loop, weld, or bolt the chain to the frame.
Might be alittle cheaper in materials this way, and fairly fast.
Ill add my .02$'
Since i dont have any idea about how you have oriented it or use it for and since it sounds as if if will be permanent. I suggest that you,
Place square footings across the width of the container in five locations, the first being one end and then every ten foot. (this will help keep your container level)
The footings dont need to be that deep , but would need to come out from the container enough so you can attach either eye bolts or steel strapping that you can bolt to the bottom of the container. ( there is no need to throw a strap or chain over your container , since it a solid piece, therefore if you attach at the bottom you are also connecting the entire container)!
Something you may consider is to berm both long sides, you could step berm adding a flower/vegetable garden to both side ( depending on your southerly orientation) This would protect your container from any and all cross winds of any type, not allowing anything to push /move it! It would also allow you to use the roof if you wanted, ( you wouldnt have to berm it all the way to the top of the container, say 3/4 height max.)
If you did berm it you may want to repaint the sides of the container to add in the waterproffing of the metal!
A ground silo/pit would work quite nicely! Heck it could be your tornado shelter! If you can secure the doors from the inside somehow!
If you have access to a welder or someone who can weld for you I have found that pouring concrete footings at the 4 corners with a thick metal plate (eg. 1/2" x 8" x 8") embedded in the top of the concrete footing makes a great attachment. You weld the square casting blocks on the corners of the shipping container to the metal plate embedded in the concrete footers. Your idea of chain or other scrap metal can also be implemented by welding those items to the bottom of the embed plate such that the concrete and steel all form a massive anchor on each corner of the container. Your idea of an auger hole is also ideal in my opinion as it gets your anchor deep into the soil.
Be sure that your anchor points are square to each other in the orientation you plan to place the container and also verify that all 4 embed plates are level with one another before concrete is mixed and poured. Most container casting blocks are close to 6" square so sizing your metal embed plate larger than that size will give you some leeway if your measurements are off slightly.
Depending upon what will go inside the container you may choose to place an additional set of footings on each side of the container at the midpoint (20 ft). Containers are designed to handle large amounts of weight supported only by their four corner casting blocks, so you can decide if your application needs the mid-span support.
With weld plates welded on two sides at all four corners your container will be significantly more "attached" to the earth than you could get with chains or rebars driven through the casting blocks.
Good luck on your project.
Mobile home anchors would work, but if the container needs to be placed on the ground it is very difficult to make those systems applicable without some working room between the item being anchored and the ground surface.
Dirt berming can be done with containers, but be advised that the sidewalls and roofs of containers are neither designed nor built for an application where pressure from dirt cover will be applied continuously. I have built with containers on rocky hillsides where the sidewall and end walls are backfilled up 2/3 of the wall, but I added additional support metal to make sure the sidewall could resist the constant push from the earth. What I used was metal cut out of the side walls of other containers to double and triple the thickness of the metal. This also had the added benefit of placing other metal between my container wall and moisture. If something does have to get sacrificed to rust, it will be one of the other layers before my container wall.
I would never attempt to bury one in dirt subject to flooding or standing water either. The result would be the same as a septic tank that was not filled with water before a big rain -- it could float out of the hole.
Your thoughts on waterproofing are also spot on if the walls will be covered.
I am still on the fence with the whole repurposing shipping containers, but honestly its just a potential toxicity thing and that they're always painted, and paint always comes off, and the fact that they're ugly. I like the berming idea, and am fully cognizant of the structural weak points of the containers. I was thinking, that I would like them a lot more if I could just treat them as a modular building unit, just add fixtures, and bury them under a forest in whatever configuration I saw fit. I was thinking that what would be necessary would be a superstructure to carry the load from the corners of the top containers to a roof that would carry the weight of, say, the makings of a forest up above. That way I don't have to look at shipping containers on my property.
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein
If you are already adding concrete footings, you might as well use anchor bolts. These are pieces of metal shaped like an L with threads at the top. You set the bottom of the L into the concrete and the threads above concrete floor grade. This is what is done for just about any industrial metal building (my profession).
Using a recycled vehicle wheel to anchor your footer sounds like it would work but I would use a 5 foot length of drill pipe welded to a round plate for the wheel end and a square plate at the top to match corner fittings of the container.
Spraying the wheel and pipe after welding with underbody coating to prevent rust and possibly using ready mix concrete to prevent direct soil contact and prevent uneven sinking as the anchor is placed under weight of the container.
Only bury 4' of the anchor and if you have not leveled the site from the highest point on the lot bury one anchor with a 1' clearance above ground and use a laser level or water level to place the other anchors at the overall height they need to be.
Using a tractor mounted Auger? if your wheel diameter is slightly less that the auger this could be a quick and easy operation to dig the holes.
I am considering using 2 ea 40' and 2 ea 20' to build a house I would use the same post and anchor footing system as your idea and I would have a 20' x 24' courtyard in the middle. the corners sections of the roof can be factory assembled as they would fit on a standard flatbed trailer
Companion Planting Guide by World Permaculture Association