Straw bales and straw bale wall systems

Abstract

Hay and straw bales can be stacked up like giant insulating bricks to form load-bearing walls for a wide variety of structures. The technique could provide home builders with inexpensive, energy efficient, long-lasting, fire-resistant, easily built, comfortable houses from a natural resource yearly renewable and locally available. Unfortunately, the lack of knowledge regarding the structural properties of the bales and the wall systems incorporating them presents a major barrier to straw-bale construction. Without the quantitative information that standard engineering testing would provide, the wider use of bale construction will continue to be severely inhibited. This thesis examines the basic mechanical properties of individual straw bales (stress-strain behavior, ultimate strength, Poisson's ratio, etc ...), and prototype wall systems (vertical strength, in-plane lateral strength, out-of-plane lateral strength, deflection, creep, etc ...). The results of the tests on the individual bales as well as the wall systems are used to develop guidelines and equations for the design of straw-bale structures.