Structural Engineers

Would Shipping Container Houses be Safer In Tornadoes?

I’ve been asked this question on my Facebook page, and it is a good question.  I originally wrote about this last spring, and I’m rewriting the post today (October 22, 2011).  The original post said no, but I’m going to change the answer to “yes and no” or let’s say – it depends.

Notice that heavy recliner that was deposited in the middle of the open area



The first thing I noticed is that tornadoes destroy in their own peculiar way.  I’ve seen buildings that have been destroyed by fire, falling trees, windstorms, and exploding bombs.  Each method of destruction leaves its own footprint.

With a fire, you have the charring of the wood, and the worst damage where the fire started.  Falling trees bash in a building where they hit, but the damage is generally localized.  Windstorms push a building over from one side.  Tornadoes are completely different.  Let me make a list:

1.  They tend to destroy worst about 10′ (2M) above the ground – see the photo above.

2.  They destroy from the outside in, like peeling an apple.

3.  They throw things – look at the debris in the picture above.

4.  The force they generate is phenominal.

Here’s another picture:

The building in the above picture was destroyed by pretty much a direct hit.  I think two people died in the tornado that did this, and while I don’t know exactly where it happened, I suspect it was in this block of buildings – the destruction was too extreme.

The problem with a container house is if you get a direct hit, there isn’t much it can do to protect you.  The debris can penetrate right through the windows and doors.  The force is so extreme it’s likely to destroy the building anyway, because you loose a lot of strength when you cut sections of it out.  You are better off with a safe room or basement (because the damage tends to be above ground, I think basements are the best).

However, what if you are on the outskirts of where the tornado hits?  The steel skin can do a much better job of stopping flying missiles than what is typically used in modern home construction – vinyl siding with thin foam sheathing behind it.  It also is likely to resist the higher winds that will hit it than conventional construction.  The first house we designed in Atlanta was unfortunate enough to be in the same neighborhood hit by the Cabbagetown Tornado.  While other houses around it had roof and siding damage, it had no damage whatsoever – although it was not in the direct path of the tornado.  In a direct hit it would have been destroyed.  However, it has a concrete subwall basement, so the owner would have had a refuge in such case and probably would have survived.

So, to modify my original point – container houses are not an adequate shelter for tornadoes in a direct hit, they can provide significant resistance to damage caused by a tornado that passes close by.



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