[GSBN] Steel mesh in clay plaster + earthquake safe fire shelters

[martin hammer]

Thanks Rob.  Point taken about mating a very strong tensile material with a
quite weak compressive material to form a(n) (un) balanced matrix.  Lighter
gauge steel would be a better balance, but would also be more susceptible to
failure by corrosion.  And then there's the cheese cutting concept under
load that you mention.  I didn't see that type of "cutting" in the PAKSBAB
seismic tests, where the specimens used nylon mesh in clay plaster.  It
seems that nylon has a similar cutting potential, but I also imagine less so
than steel.

Martin


On 8/25/13 12:38 PM, "RT" <archilogic at yahoo.ca> wrote:

> I've no experience in building with earthen plasters but I must confess
> that I did find the notion of high embodied-energy steel reinforcement for
> earthen plasters, incongruous --not only because of the obvious Greenie
> issues but because using 200 - 400 MPa steel reinforcing with an earthen
> mix whose compression resistance might be in the range of 20 - 40 kg/ cm^2
> strikes me as being akin to to using a Sikorsky Sea King helicopter to go
> to the corner store to get a bag of milk.
> 
> I would have thought that a reinforcement strategy would include bamboo if
> only because it provides a larger cross-sectional area against which the
> low-compression-resistance earthen plaster is bearing. ie I would think
> that the relatively small diameter wire of steel or plastic mesh would
> create a scenario not unlike a wire cheese cutter going through a block of
> cheese, if push comes to shove (as in a seismic event).
> 
> I had a vague memory of reading about the U.S. Army doing some studies
> with bamboo as an alternative to steel in reinforced concrete in the '60s
> of the previous millennium and a quick Google turned up the following
> document as one of the first hits:
> 
> http://www.romanconcrete.com/docs/bamboo1966/BambooReinforcedConcreteFeb1966.h
> tm
> 
> In looking through the document, the following sentence in the intro
> caught my eye:
> 
> ============ copied material ==================
> " Bamboo was given recent consideration for use as reinforcement in
> soil-cement pavement slabs in which the slabs behave inelastically even
> under light loads"
> ============= end of copied material ==================
> 
> The rest of document appears to contain plenty of useful, practical,
> factual info. like:
> 
> ======= more copied material ===============
> 
> " When using whole culms, the top and bottom of the stems should be
> alternated in every row and the nodes or collars, should be staggered.
> This will insure a fairly uniform cross section of the bamboo throughout
> the length of the member, and the wedging effect obtained at the nodes
> will materially increase the bond between concrete and bamboo."
> 
> =========== end of more copied material ==========
> 
>