Bamboo Reinforced Cob for Seismic Stability

Initial searches on the subject of cob's ability to resist seismic failure doesn't return a lot of examples or in-depth studies. Peter Hickson has performed a test in 2012 claiming cob reinforced with bamboo will withstand a 7.8 earthquake. However, I'm not finding enough literature to support this claim.

http://www.builtinbliss.com/wp-content/uploads/2013/01/UTScobtest_000-1.pdf 

https://www.youtube.com/watch?v=2CRLYQUrQw4

This quick comparison of natural building techniques is helpful on a very basic level, but falls very short of explaining qualifications.

http://ebookbrowsee.net/techniques-comparison-doc-d78863940

Many articles will state that because of cob's continuous structure and comparative thickness, it is more earthquake safe than adobe. From what I can tell, far more literature exists around the structural integrity and seismic retrofitting of adobe buildings. This is probably due to the fact that so many adobe buildings (many historical) exist in the U.S. 

         "Understanding the seismic performance of structures in terms of engineering science is of recent vintage. Only in the twentieth century did information begin to emerge on how structures respond in earthquakes. Historical building practices developed with the accumulation of experience gained through trial and error. The first measurements of ground motions in damaging earthquakes were not taken until 1933, and it was not until the 1970s that the first recordings were made of a building as it responded to an earthquake that caused damage to that structure. The first procedures for seismic design were not formulated until early in the twentieth century, although there had been some sporadic attempts prior to that time. Many assorted construction details were proposed that were asserted to provide better seismic performance. Following the emergence of modern construction methods in which steel and reinforced concrete replaced brick and stone as principal building materials, structural designs were developed that could withstand environmental loads (wind and earthquake) and perform in a relatively predictable and acceptable manner. Steel and reinforced concrete are ductile materials that have linear elastic properties and good post-elastic strength characteristics. After yielding, these materials maintain most of their strength while undergoing substantial plastic deformations. They can be analyzed with reasonable accuracy using analytical or computational methods. In contrast, the behavior of brittle, unreinforced materials—such as stone, brick, or adobe—is extremely difficult to predict after cracks are initiated, even with today’s advanced computational capabilities. Even if results could be generated with these technologies, they would not be accurate. Once yielding occurs in a brittle material, cracks develop, and a complete loss of tensile strength results. The seismic behavior of adobe buildings after cracks have developed is dominated by the interactions of large, cracked sections of walls that rock out of plane and collide against each other in plane." (GSAP 2000)

"The retrofit systems tested in GSAP involved horizontal and vertical straps, ties, vertical center-core rods, and improvements in the anchoring of the roof to the walls. Each method proved to be successful in reducing the tendency of the model buildings to collapse.

The retrofit method using vertical straps was most effective for reducing the risk of out-of-plane wall collapse. Vertical straps had little or no effect on the initiation and early development of crack damage. When displacements or offsets became significant, however, the strapping system controlled the relative displacement of cracked sections of walls, which, if left uncontrolled, led to instability. When coupled with tied anchorage to the roof and/or floor system, the out-of-plane overturning or mid-height collapse of walls can be prevented.

In-plane damage was much less affected by vertical straps. This is largely because in-plane offsets are smaller in magnitude and more likely to persist after the dynamic motions are completed. Straps can prevent large displacements but not small crack offsets. Straps are also useful in preventing piers from becoming unstable. (GSAP 2000)

 https://www.getty.edu/conservation/publications_resources/pdf_publications/pdf/seismicstabilization.pdf

To me, this shows that reinforcement is key to seismic resistance. Wrapping the structure in wire prior to plastering would be the closest to recreate the GSAP's strap method, but I'd rather find more documentation of examples using natural and local resources. Peter Hickson says bamboo is key, but I want more documentation.