From time to time we’ll post answers to readers’ questions.
Q: How do earthbag structures compare to military sand bag bunkers?
A: We know sand bags have been in use by the military for a very long time, possibly as long as 250 years. See Earthbag History Footnote.
We also know sand bags (earthbags) are still widely used by the military and in flood control due to their strength and practicality (simplicity, reliability, affordability, rapid delivery, etc).
Like their military counterpart, earthbag buildings are very strong and can be made even stronger with the use of added reinforcement. In the simplest terms, it’s like military sand bag bunkers with reinforcing — rebar pins, plaster mesh, plaster, reinforced bond beam and barbed wire. Not all earthbag structures require extra reinforcing, but it is possible to design safe, affordable earthbag buildings for virtually any environment, including hurricane, tornado and earthquake regions, and war zones.
How much reinforcement for withstanding earthquakes? Do you need “rebar pins, plaster mesh, plaster, reinforced bond beam and barbed wire” or just some of these?
Thanks.
Details will vary for each design and level of seismic risk. We currently have a licensed engineer working with us who specializes in earth construction. We hope to have free stamped plans available shortly.
If you want to use your own design, you’ll need to prioritize some of these reinforcement techniques. (Sounds like a good blog post for the future…) We believe adding fishnet or plaster mesh on both sides of the walls and tying them together through the wall is one of the best ways of adding a great deal of strength at low cost.
We’ll be publishing an article soon on this topic at EarthbagBuilding.com. You can also email me for a current draft copy. Click on About Us for our email addresses.