The container is constructed with high strength square-tube beams that run end-to-end along the top, bottom, and frame out the ends. The walls themselves, however are constructed with a staggered double layer of corrugated sheet steel. Thus the frame is stronger than the walls themselves and in a full-bury the weight of the surrounding soil will apply its pressure to all points equally. The middle point of a long wall section is thus the weakest point, and load calculations (strength calculation in /sq. inch vs load calculation in /sq. inch) should be crunched for the type of soil (density) that you are planning to install in. I have not had any luck finding engineering specifications on these containers yet. Yes, there is an industry standard for size and type but as far as the quality of steel, thickness, etc., I am not sure. Also keep in mind that a used container may have experienced more metal fatigue over its life compared to another seemingly identical unit.
Offered by Steve.
Sea containers, shipping containers, intermodal containers (whatever you want to call them) seem very sturdy, but their strength is highly concentrated to the corners. Corner strength is all that is needed to stack them 20 high (as well as handle them,) and the length supports are strong enough to prevent shape distortion. They have relatively little sidewall strength, and this can easily been seen if you look at any container graveyard. This fact makes them unsuitable for burial unless adequate measures are taken to reinforce the top and sidewalls. It will also be a concern if the container experiences any extreme circumstances (high winds, wind born projectiles, etc.) As a low cost alternative, used underground fuel tanks provide much more strength (since they were designed to be buried in the first place) though raw tanks will need to be cleaned prior to use. These are harder to find, but are a much more appropriate solution.
Offered by Michael.
The steel in the sides is usually 1.5mm or 2.0mm and most of the "raw" containers in the yard that I checked out had 2 or 3 holes in them, either from rust or from something piercing through. The job of refurbishment seemed to consist mainly of blasting or grinding the paint and rust off the surface of the container, cutting out sections of steel to replace damaged or rusted areas, welding in steel plate to replace and then painting. The floor of the containers are very thick (20-30cm I think he said) marine plywood and are very difficult to remove, apparently, or so I was told.
Offered by Gino.