Shipping Containers to be used as retainning walls 10

[pelelo]

Engineers,

To use shipping containers as retaining wall was an alternative proposed by a client at a mine site. He wants to use 2 rows of 40 foot containers, 10 ft high and about 8 ft wide, fill them up with sand and then back fill with granular material.

Has this solution worked for you?

I have 2 concerns about this:

1 - To backfill close to the wall might damage the wall. If that's the case, I would recommend to compact using a jumping jack up to 10 ft off the wall.

2 - The junction between the top container and the bottom container will need to be strong enough to avoid any driving force to slide the top container. To lock the top and the bottom containers I would recommend rebars all around. That's my thought.

Let me know you thoughts.

 

[msquared48]

I would be concerned with corrosion and performance over time.

You will not be able to compact the interior of the containers. May want to consider CDF.

Near equal compaction on both sides of the wall would help to keep the wall from failing.

Mike McCann, PE, SE (WA, HI)

 

[jdonville]

"Stream-of-consciousness" points:
Containers do have securement points and some are designed to stack, so I could see these maybe used as "bricks" for a gravity type wall.
IDK if the containers are steel all around...
Filling with some sort of sand could be difficult to not have voids to prevent local crushing which could result in alignment problems or collapse once in place - also backfill stress from external compaction equipment. If you could fill mostly with sand and then use flowfill or grout to get the voids, though...
Due to weight, would almost certainly want to fill in-place...

 

[MotorCity]

I think in theory it could work, like a gabion of sorts. Concerns would be corrosion of the containers and the ability to lock or connect them together as others mentioned.

Man, they want to build everything out of shipping containers these days......sheds, houses, apartments...now retaining walls? whats next - a space station?

 

[cvg]

have seen this done before, also at a mine property. I did not design and only observed construction for a couple of days so I don't have all the details, but it has worked well at least for short term. I believe that the containers were probably filled with rock, and maybe concrete and faced with reinforced concrete wall, with soil backfill behind the containers supporting a sidewalk (with little compaction). total height about 7800 vertical, used as bridge scour protection and placed in river bank during low flow.

 

[MTNClimber]

Doesn't sound like an inexpensive long-term solution but it can be done if you can get enough weight inside of the container. Figure out how much material they need to get into the container and see if they can do it.

I would have to think more about a good connection for the upper and lower containers. Right now, I'm thinking cutting holes through the top of the lower container and a hole in the bottom of the upper container to install a coated steel bar similar to fiberglass shear pins on small block SRE walls. But I'm sure there's a better solution.

What does the client have against normal retaining walls? If they don't care what it looks like they can just use a wrap face wall.

 

[aeoliantexan]

A common rule of thumb for gravity retaining walls is to have a base width approximately 0.7 times the height. It can be smaller if the backfill has a high friction angle and is not saturated, but 0.4 seems pretty marginal. A global stability analysis is needed. Then I would consider whether the structures can tolerate the stresses.

 

[MTNClimber]

You can just stack them 2 deep. Just seems like so much effort for no good reason.

 

[BridgeSmith]

...0.4 seems pretty marginal.

I'd say worse than marginal. I've never gotten a gravity wall to work for stability (overturning and sliding) at a width to height ratio of 0.4, even with crushed rock as the retained material. That's using the method and factors in the AASHTO Bridge design spec, but other accepted methods should be similar.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[miningman]

Before criticizing this design , please take into account that many minesites arte in remote locations and also have an excess inventory of these things, in many cases damaged beyond repeated use. The local economics may outweigh concerns re long term stability. Many minesites only last 7 years or so.h

 

[BridgeSmith]

If there are enough of the containers available, using a configuration with 3 (one buried behind the other 2) or 4 containers for the wall should be fairly stable, but a wall using just 2 stacked is likely to slide or overturn.

Rod Smith, P.E., The artist formerly known as HotRod10

 

[Craig_H]

Regarding the uncertainty of voids while filling the shipping containers, consider that the world's largest cranes use shipping containers, stacked and secured together, as counterweight. See the below photo:

Considering the necessary certainty in that amount of counterweight, it must be possible to fill containers with relative accuracy.

Regarding the connections between containers, these connections are very robust and can handle the accumulated load of stacked containers under sea-fastening load cases (picture a container ship rocking back and forth in rough seas). There's an ISO standard out there for shipping container dimensions and I am sure that it provides design guidance on the connection strength. All the strength in a container is in the four corners, so whatever you do, make sure that the stacked containers bear at the four corners. If my memory is right, we counted on containers to handle about 300 metric tonnes of vertical static load, which makes sense (allowable weight of a container is 30 Te, I guess you can stack them pretty high)

 

[MTNClimber]

"A 40-foot container’s empty weight is 3,750kg and can be loaded to a maximum overall weight of 29 tons (26,300kg)." - Some random website.

A shipping container "full" of soil probably weighs around 330,000 pounds which is far more than the 29 ton (58,000 lb) capacity.

Not sure that a ship rocking back and forth is comparable lateral earth pressures but maybe it is. But the horizontal force could be around 75 to 85 kips on the upper container. The connection is just something that needs to be checked.

 

[Ceinostuv]

Based on the testing requirements in ISO 1496, the corrugated panels that run across the top of the container, which are similar if not the same as the wall panels, are tested up to the equivalent of 72 psf over 8'-0". If these are going to be filled, you could fail the wall panels but maybe it's not that big of a deal if these will end up buried and bowing of the walls is a non-concern.

The standard connectors, which are generally a Tantlinger-style Twist Locks, usually have capacities that exceed 90 kips depending on who the manufacturer is. But, using these connectors will leave you a gap up to 6" between the containers. There aren't really any options that will give you a zero-gap between the containers, as even the shipping knuckles (some manufacturers call them foundations... ugh) project a couple of inches above the top of the container.

As MTNClimber stated, it seems like a lot of effort for no good reason.

FYI MTNClimber, they test those connectors with the 90 kip force to simulate a ship rocking, essentially the condition in the video. Pretty good guess at the 75-85 kips based off of a video, kudos!

Judgement-In-Training

 

[MTNClimber]

I didn't know we had a bunch of box engineers in here.

 

[Ceinostuv]

I didn't know we had a bunch of box engineers in here.

I do structural! I just have... creative clients...

Don't confuse me for these guys!
[URL unfurl="true"]https://en.wikipedia.org/wiki/Packaging_engineering[/url]

Judgement-In-Training

 

[MTNClimber]

Haha, I'll do my best but no promises!

Well I wasn't really clear in my post. The 75-85 kips would be the estimated soil pressure assuming good soil being retained. That value could easily double if clay is used, a surcharge load is introduced, and/or if the backslope is inclined. Sounds like the connections could be an issue if we're looking for a FOS of 1.5 or better.

 

[miningman]

Why would the client need a FOS of 1.5??? A lot of mine engineering is done with an FOS of 1.15 or less.

 

[Ceinostuv]

Well I wasn't really clear in my post. The 75-85 kips would be the estimated soil pressure assuming good soil being retained.

Ahhh, that makes more sense to me. They are actually tested for 90k each, so maybe it's still ok?

Isn't the FOS of 1.5 from IBC? What code are mines governed by? Outside my element... forgive the ignorance

Judgement-In-Training