Strawbale Archive for March 2002

But enough of that for now, until I see the test documentation.

I  think that it may be  even more inappropriate to take the results of Jeff's 
bales-on-flat tests and apply them to loadbearing bales on edge in
drawing conclusions about bales-on-edge performance in a loadbearing
design.


Ben also wrote:

>	 In fact there was really very little 'compression'even under 
>	great compressive pressures (as applied by a 1 tonne come-along).  
>	My take on this is that the grain is vertical, like it grows in the field 
>	and just like it would take considerably more force to bend a bundle 
>	of 2x4's if pushing down while they are standing on their end 
>	than the same bundle laid horizontally with the force applied from 
>	above in the middle; it is similarly difficult to squish bales on edge.  
>	Standard stick frame walls aren't built with the studs set horizontally 

Flattened straws (as in a wheat straw bale) are more akin to strips of paper 
than they are to 2x4 studs.

And flattened straws in a bale would be more akin to a telephone book
than they would be to a skid of 2x4 studs set horizontally.

If you stand a telephone book on end and stand on it, it will likely
collapse whereas a telephone book laid flat will bear the weight
of a person quite easily.

But back to bales. 

Since the stressed-skin panel action of a loadbearing SB wall panel
depends upon the bale core working together with *both* the interior 
and exterior skins ,  there must be a good connection through the bales,
joining the two skins.

As was illustrated in the pipe-grasping analogy in my previous post,
individual pipes can be easily separated from the pile  when grabbing
the sides of the pipe (as when applying plaster to the broad face of bales
on edge) and in the case of a bale, there is no connection between the two
plaster skins other than the though-bale stitching whereas with bales on flat,
all or most of the straws would be contributing to a connection between 
the two skins.

As with a telephone book, if one binds the book together with closely-spaced
straps to keep the pages from delaminating from each other, it will
bear some load without collapsing when stood on end. However, the integrity
of the telephone book (and bales on edge) is highly dependent upon the 
banding's ability to keep the pages together, working as a unit.

Similarly, if one puts hardcovers on the phone book , the fact that the pages
can delaminate easily when stood on edge, severley  compromises the
reliability of the "system" as a loadbearing element.


> I have heard it said (although know of no studies) that bales on edge
> have a better R-value per inch but while at less inches in width in nets 
>about the same as the bales laid flat.  Anyone know of any such data?

My goodness.  Poor JoE. 
How soon they forget.
One of the people who was largely responsible for the existence
of this Listserve was JoE McCabe, first List Mom Emeritus.

It was the research that JoE did for his Master's thesis which gave the
SB community the information that we have today regarding the thermal
resitivity of straw (as distinct from the thermal resistance of SB wall 
assemblies).  It was his research which determined the different 
R-values for different orientations of the straw fibres and is the 
research which is cited in the early publications (including CMHC 
reports).

Last time I looked, JoE's thesis was still posted on the WWWeb .


--- * ---
Rob Tom
Kanata, Ontario, Canada
<ArchiLogic@yahoochaff.ca>
(winnow the "chaff" spamguard from my edress in your reply)

Please visit http://www.theHungerSite.com daily



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