Earthbag Technical Report from Nepal

Good Earth Nepal has published this PDF on its site.

Before presenting some highlights I would add that there are a few details which, to my understanding are only correct in the context of typical above ground houses, less so with bermed or underground structures.

“At present, there are over 15,000 Earthbag buildings worldwide with recent Earthbag  constructions gaining approval under strict US building codes.

An estimated 55 Earthbag structures built in Nepal survived the 2015 earthquake, in regions ranging from Solokumbu to Sindhupalchok to Kathmandu.

… The main material of an Earthbag structure is ordinary soil obtainable at the worksite.

… A study by the U.S. Federal Highway Administration found that the half -life of polypropylene fabrics in benign environments can be 500 years or more. The
bags themselves have a tensile strength even higher than that of steel, and can resist circumferential forces generated from the weight above.

… An Earthbag building uses its own weight to anchor itself to the rubble trench foundation. Since the superstructure is not attached to the foundation by bolts or rebars, the foundation and the
superstructure are able to move independently minimizing the shock transfer to the walls. A rubble trench is also built of individual units rather than a continuous beam further absorbing the shock.

Earthbags are resilient. As per an experimental study on vibration reduction … Earthbags have a relatively high damping ratio with horizontal as well as well as vertical vibrations effectively reduced.

… All of these components make Earthbag structures extremely earthquake-resistant. Tests done in accordance with IBC standards have found that Earthbag construction far exceeds Zone 4 standards, devised to protect against the very highest level of seismic activity. Numerous Earthbag structures have been built in the United States. Earthbag structures are permitted by the California Building Code, the toughest in the United States due to high seismic activity.”



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