Strength of cargo containers?

It depends somewhat on the box's construction and age. As you state, the corners are designed to bear the weight, but the skin is often pretty tough. Usually when you bury them, you only do a foot or so on top. Bigger problem is the side buckle from side pressure.

Realize even a short box (20 footer) is a crap load of dirt. You're looking at three truck loads at least. A backhoe is going to take some serious time to dig this out. And depending upon where you've located the story, you got the potential for bedrock and/or large buried boulders.

If you want to prevent buckling, you need lolly columns, either vertically or horizontally, with pads to spread the internal pressure. If you've ever seen these things after a train wreck at speed, you'll see how tough they are.

Long term corrosion is going to do you in.

Best of luck,

Jim Clark-Dawe

Angry Guy said:

The cargo containers that get transferred from ships to trains to trucks -- how strong are they? I know you can stack them 5 high, but that's mostly supported at the corner columns. I'm concerned about burying one under 3-4 feet of earth. Would it hold or buckle? What about if I placed 2x12 boards or something across the top to transfer the load to the sides?

I guess I'm not really looking for an engineering opinion (although that'd be nice), but more like "is this a throw-the-book-against-the-wall".

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There's only one way to know for sure, if you have a box to bury.

As was pointed out, there is variation, but I think this is want you want for information:
https://law.resource.org/pub/us/cfr/ibr/004/iso.1496-1.1990.pdf
or
http://www.steinecker-container.de/container/Container2/Spez-Container/Spez_high cube20.pdf

The second one looks more usable. After looking at the specs I think that I wouldn't want to drop a boulder on the roof panel, but sand runs about 150 lbs/cubic foot, and I think the roof could take that.

I was looking through King Neptune's site and the specifications and realized there's a real easy way to strengthen the roof. Flip the box upside down, so the floor is the roof. You'd need to deal with the roof ribs that are now on the floor, but some plywood would solve that problem.

Big danger for containers is a puncture, not a collapse. A fork lift can puncture the side with the forks. If this happens when the container is in motion, it will start to peel.

Best of luck,

Jim Clark-Dawe

http://graywolfsurvival.com/2625/why-you-shouldnt-bury-a-shipping-container-for-a-shtf-bunker/

Unless the container is prepped, it is not worth the effort.

I should have thought to ask whether this was a short-term (less then a month) or a long-term situation.

Best of luck,

Jim Clark-Dawe

Working below grade is always a problem. The earth is constantly pushing to fill the void.

How large does the area have to be and how long does it have to survive? Days? Months? Years?

What technology do I have available to me? Do I have the ability to locate this in an ideal situation? How much building time do I have?

If I had the building equipment available, and needed just a small area, I'd use a new precast concrete septic tank. You can set it up for positive ventilation, but that's going to create a surface impact.

Understand that you need to deal with power and ventilation when you go below grade. Even in an open topped ditch where you have powered equipment in the ditch you can have a C02 problem.

And some of this depends upon how accurate you want this to be.

ETA -- I checked and a 5,000 gallon septic tank will have interior measurements of 7' x 16.5' with plenty of head room. You have three manholes in the top, using one for entrance and intake ventilation and passively venting by using a second manhole with a ten foot vent pipe. Weight is about 54,000 pounds. These suckers are made and stored for use. Concrete requires setting time before it can go into the ground. Intake and outlet pipes are sealed and you punch open the ones you need for use, so there's no leakage from them. A concrete company should have the equipment to move one.

You coat it with a tar solution for waterproofing, and you should be good for 50+ years.

Best of luck,

Jim Clark-Dawe

Shipping containers can be buried and work well as a bunker.

Seen it done.

Probably last 10 years or so in a moderate climate.

Angry Guy said:

Hm, it's looking like this is a non-starter.

Basically, this is for the second book in my series. My protags will have to set up a structure that will be in the same place on alternate earths, and should be as protected as possible. I was thinking that shipping containers are easily available, standard sized, and reasonably roomy. And burying each version in the same place would afford consistent protection.

They can't order anything, what with civilization having broken down and all, and I'd rather not have them doing a lot of construction, i.e. concrete and girder stuff.

I'm just wondering what you might find lying around in town that could be used to make something appropriate?

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As Drachen also commented, shipping containers can be buried and survive for years. There is a great deal of variation in containers. The one that I found the specs for in medium grade. The light weight ones you can shred with a pocket knife, and the heavy shipping containers have corrugated walls and roof. If you are shy about the shipping containers, then look at the containers that demolition companies use for store explosives; the side walls are rather heavy, and the rooves are removable, so the explosion will go up in case of accident.

Angry Guy said:

OK, here's the full situation. My MCs have an interdimensional gate technology that allows them to travel between alternate earths. They can't "tune in" to any world they want, like stargate. It's more like a subway. A connects to B which connects to C, etc. And it connects to the same geographical location on the next earth. Some earths are not friendly (one never experienced the Yucatan impactor). So I'm visualizing them setting up a series of underground containers with a gate at each end. As you walk through them, you're moving between realities. Obviously you also need an exit from the container when you get to the earth that you want, but that's more of a detail.

For ventilation, I can just use some kind of forced-air system at every 3rd container or something.

The other problem - and I just thought of this as I was typing -- is that materials have to come through the gates, so I guess I can't use a completed structure like a shiping container. I should probably be thinking of this more like mining, where you're digging shafts and bracing them.

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I think that Poul Anderson wrote something like that, but I don't believe that he wasted words describing the structure. There were exit doors every now and then. The exits led into the various worlds, and I think that any ventilation was through them.

If you find it necessary to describe the structure, then your idea of a rocky tunnel would work. Is whatever created it still working through the tunnel? Could that be holding the rock up?

If you decide that you need some physical structure, then consider precast box culverts. They are designed to be buried, and roads are built on top of them. They are more than strong enough.
http://www.ncp-inc.com/boxes.shtml

Drachen Jager said:

Shipping containers can be buried and work well as a bunker.

Seen it done.

Probably last 10 years or so in a moderate climate.

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The one time I've seen it done was a complete disaster. The sides were caving in, which caused the doors to warp and not close properly. The moisture in the soil ate through the floor and sidewalls, which caused humidity and water damage to the ammunition stored inside. Termites got inside the container and ate the pallets the ammo was stored on and the boxes it was stored in.

If you were going to make a bunker out of an ISO container the I would suggest that it is placed upon a concrete slab, have either concrete walls or concrete block as walls, and then a concrete slab as overhead protection.

Angry Guy said:

OK, here's the full situation. My MCs have an interdimensional gate technology that allows them to travel between alternate earths. They can't "tune in" to any world they want, like stargate. It's more like a subway. A connects to B which connects to C, etc. And it connects to the same geographical location on the next earth. Some earths are not friendly (one never experienced the Yucatan impactor). So I'm visualizing them setting up a series of underground containers with a gate at each end. As you walk through them, you're moving between realities. Obviously you also need an exit from the container when you get to the earth that you want, but that's more of a detail.

For ventilation, I can just use some kind of forced-air system at every 3rd container or something.

The other problem - and I just thought of this as I was typing -- is that materials have to come through the gates, so I guess I can't use a completed structure like a shiping container. I should probably be thinking of this more like mining, where you're digging shafts and bracing them.

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So, the 'moving between realities' means you don't need the containers to be living quarters, etc. Just a means of separating the 'gates'? And the containers don't need to be a particular size or length, (the alternate dimensions aren't actually 20 or 40 feet apart) as they're just a gate-holder and sort of a placemarker for the traveler?
How big is this gate? How much space does it take up? I'm going to assume that it's 'wall-thick', as in: it wouldn't be any wider than a shipping container wall. How high, how wide? Because the smaller the space you need, the stronger you can make it.
So, you're looking at a space big enough to hold a couple of people for a short length of time, with a third door as an exit?
How about elevator cars? You can get them with doors front-and-back for going into the 'back rooms' of buildings, and they have those emergency escapes in the ceilings (or at least they used to.) I assume they're sturdy enough to take being hauled up and down, with a weight of people on them (I don't know how they handle impact, when the brakes fail or whatever.)
* I know you don't want to have to do construction, but if the size of the gate is the constraining factor, concrete block construction with rebar reinforcement sounds like the way to go.

Angry Guy said:

You're pretty close on your assumptions. the gates can be made to any size, but the MCs have standardized on a six foot by three foot ellipse. I haven't specified a thickness, but we're talking inches. The space in any earth just has to be big enough to accommodate a gate at each end, and an exit to that planet -- which could be a ladder to a manhole or a door to steps going up. Haven't settled on it yet. But again, it has to be something that can be put up quickly and easily, and the materials have to be able to fit through a gate (they also have one gate big enough to get a truck through).

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That six foot by three foot ellipse really limits it. I think that Frimble's idea of concrete blocks with reinforcement would be the best you could do, unless the gates can be stretched under certain circumstances. In fact, you'll have to do that, or the truck will be stuck in one place.

If you only need 6 x 3, I'd look at culverts or underground piping, either metal or plastic. They come in lengths of ten feet or longer, but can be cut to the right height. Can easily be manhandled by a man who's strong enough to dig the hole.

You start by marking a circle and digging down about three or four feet. At that point you're beginning to deal with collapse danger, so you put your culvert in the hole for support and continue digging, letting the culvert gradually settle further and further into the hole. Roof/cover can be made with heavy timbers.

Two people could reasonably dig this in a day with shovels. Culverts are designed for loads. Easy to transport through your portal. Your readers will know what a culvert is without a lot of explanation.

Best of luck,

Jim Clark-Dawe

Remember that only one guy can dig in a hole at the same time. As you get deeper and deeper, removing the dirt becomes more and more difficult.

Culverts up to eight feet diameter and ten feet long can be easily carried on a pickup truck. A state's department of transportation would normally keep lengths available in various diameters for repairs. A highway construction work site would be another source for finding them.

Best of luck,

Jim Clark-Dawe

Oh, you've probably already thought of this, but if you have a number of gates, and they all reliably link to a particular version of Earth, you might want to label them really clearly, as to which is which. In case your characters need to get somewhere in a desperate hurry, and miscount as they're going along.
A string of identical culvert-sections can be hard to tell apart.