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Anyone use shipping container as concrete form?

FredC

Titanium
Joined
Oct 29, 2010
Location
Dewees Texas
Those have a strap thru the concrete, much like the industry standard of snap ties & Jahn clips.

The container form has no such bracing.

It has been 20 or so years since I saw those forms. I just remember those straps as nothing to write home about. I could think of several ways to do a little bracing on the walls and do the same procedure in pouring to minimize the pressure. First thing that came to my mind was drilling holes in the wall and driving rebar in to the surrounding soil, then cut it off and weld it. Give me another hour and I might think up a better plan.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Anyone here done a house or a wall with Integrated Styrofoam Forms or seen it done? I have seen the forms, seem like that were 2 inches thick inside and out with plastic straps tying the sides together. I never have seen them filled with concrete but that 2 inch foam has to be weaker that the sides of a shipping container. Just guessing but the secret maybe is going around the structure and pumping in the concrete a foot or so at a time. By the time you get around the house the first concrete has probably partially set?

I was going to have my house done with the ICF walls for a time, but I dropped back and punted with cinder block walls with the Styrofoam glued to the outside.

The roof would need some thinking from what has been said, it will need rebar. Anything wrong with welding the first run to the roof with spacers to hold it off the roof?

Like anything else, there is math StackPath
 

boslab

Titanium
Joined
Jan 6, 2007
Location
wales.uk
I’ve used these a bit, they held a 12” slab up without drama, though the pouring and vibrating was drama enough for me, I have 4 peri props that I OES as a welding bench, I stuck 3 1/2 ton on that, it didn’t fail
MULTIPROP Aluminium Slab Props
Bear in mind formwork is pricy, you can edge some floor form easily enough.
I admire your thinking btw
Mark
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
It has been 20 or so years since I saw those forms. I just remember those straps as nothing to write home about. I could think of several ways to do a little bracing on the walls and do the same procedure in pouring to minimize the pressure. First thing that came to my mind was drilling holes in the wall and driving rebar in to the surrounding soil, then cut it off and weld it. Give me another hour and I might think up a better plan.

...and yet....for some strange reason, the industry has gone with thru rods called snap ties......for maybe 50 years now.
 

guythatbrews

Cast Iron
Joined
Dec 14, 2017
Location
MO, USA
It would only be on the sides. Every few feet some of the rebar from the bottom slab would be bent inward and welded to the containers to keep them in position.

I think I would be more worried about shifting the containers side-side during the first lift than the container floating up. I think the mud would tend to apply a down force to top of the beam at the base of the corrugated wall.

You might want to think about the buoyant force. It will be equal to the weight displaced volume of concrete. That is if any of the concrete can seep underneath the container. The mud on top of the beam won't hold the container down any more than a ridge on the bottom of an empty pail would hold the pail down in a tank of water.
 

dgfoster

Diamond
Joined
Jun 14, 2008
Location
Bellingham, WA
It is not accurate to suggest that the pressure experienced by the side walls of the container are a simple calculation of weight/height as if the concrete to be installed were a pure liquid like water behind a dam. I learned from a cement truck driver 40 years ago who saved my bacon by suggesting we pour my retaining wall in lifts spaced apart in relatively short time intervals. He correctly advised me that pouring say 18" and waiting for Maybe 15 or 20 mins and then pouring another 18" subjected the forms to far less pressure than pouring 36" in a single lift. (I'd have to check with someone knowledgable about the needed time to wait since it has been so long and I have forgotten the appropriate intervals.) The concrete starts to set in a fairly short time and becomes a semi-solid pretty quickly (that is why the delivery trucks have their drums rotating and constantly aggitating the fresh cement) thus reducing hydrostatic pressure dramatically.. So, whatever bracing you do, pour in lifts.

That said, shipping containers are pretty carefully engineered to function well as shipping containers but are quite flimsy, really, when subjected to unexpected loads or are altered. I think the OP understands this or would not be asking. My answer is a ridiculous "quite a bit of bracing required." But, that same bracing will be much more effective if the concrete is poured in lifts and if the loading is symmetric. In other words, directly opposed wall struts will provide considerable resistance to buckling if the opposing walls are poured in lifts so that an equal height of concrete is poured more or less simultaneously behind opposing walls vs pouring one wall on one side fully and then moving the pump spout to the other side. I would suspect that just pouring a lift on one side and vibrating it into place properly and then moving to the other wall and doing the same would provide enough set time so that you could then repeat the sequence.


I am sure that someone more current on this than me can properly advise you. But this is an idea to have in mind come pour time.


Denis
 

52 Ford

Stainless
Joined
May 20, 2021
You know there was at least one guy who said "that ain't going nowhere"
LOL I think it they prolly said something more like "yah kaheen nahin ja raha hai!"

Clearly needed at least 25% more bamboo poles lashed with reeds.
 

MaxPrairie

Hot Rolled
Joined
Jul 9, 2015
Replying to above. There is a lot of liability and responsibility a structural engineer takes on when designing and sizing members/components. This is why they use design values and standards set by codes. The concrete form is essentially a temporary retaining wall which if you were to substitute the 150 for 100 lbs per cubic foot you would have the design loading for a 10ft retaining wall. My friends still practicing engineering would not put their stamp on bracing with the assumption the pour would only be done a couple feet at a time. Not trying to be a dick just explaining what my side of the table looks like.
 

dgfoster

Diamond
Joined
Jun 14, 2008
Location
Bellingham, WA
Replying to above. There is a lot of liability and responsibility a structural engineer takes on when designing and sizing members/components. This is why they use design values and standards set by codes. The concrete form is essentially a temporary retaining wall which if you were to substitute the 150 for 100 lbs per cubic foot you would have the design loading for a 10ft retaining wall. My friends still practicing engineering would not put their stamp on bracing with the assumption the pour would only be done a couple feet at a time. Not trying to be a dick just explaining what my side of the table looks like.

Couple points:
A dam holding back a lake 100 miles long has to hold back the same force as the same dam holding back a "lake" only 1 foot long. So, the width of the wall 8" vs 12" vs 16" produces the same form pressure if you treat the concrete as a simple liquid.

I do not think the OP is looking for an engineers stamp so much as practical and safe advice. There is a difference just like advice sought here on various design ideas for items that would no way qualify for an engineer’s stamp but might be quite safe and practical based on common experience. The engineer has to figure that high fluidity concrete is used (not likely in this case) and is poured as rapidly as practical and will design his forms and bracing accordingly. My point was that considering the ready mix you get from the local concrete supplier will not have, unless specified, the specialized liquifying agents that might be used on a high rise any more than very expensive but available lightweight concrete will be used. And my point was that it is possible to use much lighter and less expensive forms if he uses some "common sense" whjch may not always equate with common knowledge on a machining forum but would be common knowledge on concrete forum.

The non-liquid behavior of concrete as a consideration for form design and other factors are discussed here:

Concrete Formwork Loads and Pressure Calculations - The Constructor

Here is the relevant excerpt:
" Internal pressure resulted from accumulated depth of placed concrete is imposed on vertical formworks such as walls and columns. During vibration and for short period after vibration, placed fresh concrete close to the top and to a small depth of formwork behaves like a liquid and impose lateral pressure on the formwork that is equal to the vertical liquid head. Fresh concrete is granular with internal friction but vibrations eliminate bonds in the mixture and generate liquid state. There are different reasons such as placement rate, concrete temperature, and internal frictions that affect lateral pressure of below vibration controlled depth and make lateral pressure smaller than liquid pressure head. When vertical placement is carried out at slow pace, fresh concrete could have time to start stiffening. Moreover, unless concrete temperature is low, the time to start setting is not short. Other factors such as pore water movement, creation of friction and other parameters may lead to decline lateral pressure. Various types of cement, admixtures, cement substitutes, construction practices might influence level of lateral pressure. Mostly, concrete lateral distribution pressure, which based on tests, is depicted as shown in Figure-1. The distribution begins close to the top as a liquid and reaches peak value at lower level. For design reasons, it is suggested that ultimate pressure is uniform at conservative value.
pressure-distribution-on-concrete-formworks.jpg
"


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Denis
 
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M. Moore

Titanium
Joined
Jun 8, 2007
Location
Vancouver Island, B.C. Canada
I would use insulated concrete forms, ICF's for short. They are an excellent product and very easy to use. Just follow the instructions as they are fully engineered for the task. I have done three buildings with them and my shop has 10' tall walls for the lower floor. It was partially buried so the walls were retaining and we used the 8" forms for that pour.

Use the ICF's for your walls and the pandeck for your ceiling. Not all ICF's are the same and I prefer the type that are fully assembled and ready to stack, it is best if the plastic ties show through on both the outside surfaces as this is helpful for the next steps. They go together like lego, very easy. If you use the 8" concrete size and your soil is decent then you probably don't need a footing, just set them on a nicely levelled and compacted surface. You can cut away some of the foam at the bottom to enlarge the footing but need to reinforce that area for the pour. With proper rebar the walls will form an incredibly strong grade beam tied together with the roof pour.

I would be inclined to set the wall forms and pour the walls and then set up for the roof pour. All concrete walls are poured in lifts, it is standard practice. Are you going to have a concrete floor inside your tunnel? Is it just a walk through or will materials need to pass through?

I think that containers is a reasonable idea if you had them sitting around but may be more hassle than it is worth. 70' = 3.5 containers, doors need cutting off, floors need connecting, condensation on steel, etc etc.

I can go on at length about the ICF's as I am a real fan and love living in our house that is made with them. There are many benefits to the system and I would be happy to answer any questions if you decide to go that route.

Also just a note for those suggesting that rebar be welded to the container, this is not a good idea as the rebar needs to be fully surrounded by concrete. Also cement comes in a bag and is an ingredient of concrete, just like flour is an ingredient of bread and no one calls a loaf of bread a flour loaf.
 

neilho

Titanium
Joined
Mar 23, 2006
Location
Vershire, Vermont
The sand idea is cool, especially if the tops of the containers were taken off. Dump sand in from above and compact. Could happen concurrently with a wall pour if you were really careful. And it wouldn't have to be sand, could be almost anything - prob the excavated dirt would be the handiest and cheapest. Gonna compact better, too. A skidsteer with a full bucket run back and forth over fill compacts it pretty well if it's done in lifts.

If dirt were used, one could even arch the ceiling. The arch wouldn't need much, if any, compaction. The concrete on top will only have 12" of head.

And if the ceiling were arched, one could get by with considerably less than 12" of concrete....

Food for thought, or maybe just speculation...
 

dgfoster

Diamond
Joined
Jun 14, 2008
Location
Bellingham, WA
The sand idea is cool, especially if the tops of the containers were taken off. Dump sand in from above and compact. Could happen concurrently with a wall pour if you were really careful. And it wouldn't have to be sand, could be almost anything - prob the excavated dirt would be the handiest and cheapest. Gonna compact better, too. A skidsteer with a full bucket run back and forth over fill compacts it pretty well if it's done in lifts.

If dirt were used, one could even arch the ceiling. The arch wouldn't need much, if any, compaction. The concrete on top will only have 12" of head.

And if the ceiling were arched, one could get by with considerably less than 12" of concrete....

Food for thought, or maybe just speculation...

I would be concerned (almost certain in fact) that filling the container with sand would collapse it outward. That would be a certainty with the top off. Think of the container as a cardboard box…. Not far off. It’s strong all taped up top and bottom but very weak with the top off. And does not resist lateral loads from within or without well regardless.

Denis
 








 
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