[Cob] Cob Studies: Civil Engineers: U of BC: Materials testing

[Shannon C. Dealy]

On Sun, 24 Sep 2006, drub wrote:

[snip]
> I would *love* to have cob gain traction in the building codes.  It looks
> like the cob formulations present the biggest challenge to that objective.
> It must be terribly difficult to standardize cob formulations, since the
> core ingredients vary so widely, based on location.  Without standardized
> formulations, it would be terribly difficult to quantify performance and
> build that data into building codes.  Still worth a try.

I'm not exactly sure what you meant by "standardize" cob formulations, 
in my view the best approach would be to go the route that the timber 
industry does in the codes (they also deal with a product that varies 
tremendously), they simply devise a set of ratings based on the grade 
and type of the wood.

For cob what we need are a set of reasonably simple and inexpensive tests 
that can be performed on site and plugged into one or more formulas to 
"grade" the cob.  Using this approach, an experienced cobber would be able 
to vary the mix to get the best grade from the available materials, then
based on the grade we should be able to adapt the design requirements 
using some standard tables.  In much the way that different grades of 
lumber might require thicker or thinner boards to support a particular 
roof or floor load, cob walls might be required to be thicker or use a 
defined minimum level of supplemental support system depending on wall 
loads, seismic issues, etc.

FWIW.

Shannon C. Dealy      |               DeaTech Research Inc.
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