Shear Strength Wall Test Report

Test description: Shear strength of plastered 4′ x 4’/ 1.2 x 1.2 m bag wall (15″ / 38 cm thick) of weak cohesive soil with barbed wire; Materials: solid poly bags, tamped subsoils of silt and clay, lime and earthen plaster

Earthbag is a growing sustainable building technique that is increasingly desired in the developing world because it costs only a quarter as much as concrete block walls, is easy to learn, and does not require power tools. Because other geo-textiles perform well in hazardous areas, earthbag is desired in seismic risk areas. But structural testing is needed to determine safe plan and construction guidelines for different levels of risk.

Earthbag is usually built with cohesive earthen fill. Because it is often designed to fulfill adobe building standards, earthbag can be compared to adobe test and standards values to provide safe guidelines for use in the developing world. But to date almost all research by engineers has been limited to the structural performance of atypical sand-filled bag walls.

To explore the shear strength of a weak cohesive fill, a plastered earthbag wall portion was subjected to static diagonal compression. The earthen- and lime-plastered test wall was still stable after surpassing peak strength. With no reinforcing mesh, its peak shear strength was superior to most sand bag walls tested, and comparable to one with cement stucco reinforced with chicken wire. More rigorous testing of both weak and strong cohesive fills in earthbags is merited.

Source: Shear Strength of Earthbag Wall with Weak Cohesive Fill
All earthbag tests to date are compiled on our Earthbag Testing page.

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