[GSBN] Bales for Haiti

[RT]

On Sat, 20 Feb 2010 10:34:21 -0500, Derek Roff <derek at unm.edu> wrote:


> Max says, "My result for small family shelters the building of 1000's
> of simple rectangular shelters out of bamboo re-enforced (in hexagon
> grids!) cob, with light weight roof structures with fair overhang and
> significantly 2 doors: [snip]
>
> I still haven't heard from BWB what is wrong with this reasoning and
> suggestion"


I find it curious that the focus seems to be mostly on the walls for the  
proposed constructions and only a hand-waving gesture towards the roofs --  
"curious" because the roof is probably the most important component  
contributing to effective shelter and the one that is most likely to kill  
the building's occupants when building failure occurs as a result of  
seismic activity.

Much as I hate to admit, I think that Dubya (aka former US president  
George W. Bush) got it right when he quipped/smirked in a sound bite when  
asked how people could best help the victims in Haiti:

    "Just send cash. We'll know what to do with it."

(the "we" being the relief organisations on the ground in Haiti and having  
the expertise and wherewithal to be effective in a timely fashion)

And I can't help but think that it is arrogance that allows First World  
nat-builders to believe that they can, from afar, prescribe a univalent  
nat-build solution to solve all of the housing problems for the "natives"  
of Third World countries when in fact, the reality is more likely the  
other way around ... we First Worlders probably could learn much about  
natural building materials and methods from the people who inhabit those  
Third World nations.

I can come up with at least one "what is wrong with this (Max's) reasoning  
and suggestion" for Haiti.

My guess is that Haiti is subject to being hit with hurricanes on a  
regular basis (hence the predominance of heavy
masonry construction in that region) and "lightweight roof structures with  
fair overhangs" would likely be torn off by next season.

For our purposes (ie builders), to paraphrase Dubya, the best solution may  
be to:

    "Just send steel".

I assume that Haitians are fully capable of designing and making buildings  
that are appropriate for their specific set of requirements (cultural,  
climatic etc) but are perhaps lacking in the expensive materials like  
steel that would have prevented the destruction of their heavy (largely  
unreinforced) masonry structures.

However, I'm not suggesting that we send a shipload of steel I-beams and  
steel reinforcing rod to Haiti.

I'm guessing that whatever wall-building methods and techniques are used  
by BWoB in Haiti and elsewhere, pre-formed steel roofing probably plays a  
major role in the design of the roof.

However, light gauge sheet steel roof panels will in most cases, still  
require a structural framework to carry it, and my guess is that in most  
cases, that framework is timber ... timber that may be in short supply in  
the stricken regions, as is the case in Haiti.

It would seem to make sense that something along the lines of  
pre-fabricated/pre-engineered corrugated steel arch structures might be  
useful in any BWoB housing response. They are basically thin-shell  
structures combining structure and cladding . They are comprised of a  
module that is small and light enough to be handled by one person, that  
modular panel being bolted to similar modules enabling clear-span  
structures to be erected very quickly by small crews of two or three  
unskilled labour.

An additional non-structural benefit of steel roofing (besides having high  
recycled content initially and easily recyclable after the structure's  
useful service life) is that it can immediatly be used for rainwater  
harvesting, potable water usually being in critical short supply after  
events like quakes and hurricanes where infrastructure may be destroyed.

In the case of tropical locales like Haiti, I think Living Roofs would be  
beneficial in providing respite from the hot equatorial sun and structural  
steel thin shells could be fully capable of supporting the growing medium  
for a Living Roof.

Again, I'm not suggesting that WonderSteel quonset huts are the ideal BWoB  
response but perhaps as a model for an idea, it might be useful to  
consider.

Along those lines, an idea that comes to mind now (ie minimal thought  
invested) is a BWoB Emergency Housing Response Kit that might consist of  
galvanised steel wire gabion baskets and pre-engineered/pre-formed  
corrugated steel arch panels.

The gabion baskets would be filled with whatever material is locally  
available at the sites (it may be broken concrete in urban areas, it may  
be cellulosic crop or forest residues in rural areas, it may be inorganic  
solid waste or stone rubble in either) ... with or without thermal  
insulation placed in the cores, as appropriate for the specific locale ..  
and then stacked into walls like strawbales, the wire baskets being  
clipped to each other  ... and then plastered over, embedding the mesh ...  
while at the same time, a small crew is assembling the steel panels into  
arches ready to be set atop the gabion walls.

There would likely need to be a few tie rods installed to replace the  
function of the perimeter ring-type grade beam that is typically provided  
to prevent the vault from spreading under load.

Again, this is just a not-very-well-thought-out model to be investigated  
for the future , NOT an idea to be taken/applied literally.




-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada
<A r c h i L o g i c  at  Y a h o o  dot  c a >
(manually winnow the chaff from my edress if you hit "Reply")
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