[Cob] XL Earthbagging

[Benjamin Brownell]

Well, I confess!  My recent standing work is an exuberant dirt-ship dome of diameter=25' height=16', walls finished to 16" thick--with a 7'x12' bay window opening at ground level.  I feel that a well designed and executed project of this scale and larger can be securely accomplished and durably enjoyed, even in high seismic territory, based on fairly intimate intuitive study and exploration of this case alone.  Alright, from an engineering standpoint that's not based on much!  And it is potentially a treacherous encouragement to anyone approaching alternative construction as a guarunteed incremental advance of the Standard Issue/mass-deployable/code-conformed Units.  But I want to give an empathetic holler to the many denizens of a fulminating gray area between manufacture and artistry where crucial proof puddings are actually being prepped--most readers here I believe.
Gambling thus is often win-win (lots yet to learn from mistaking as well).  BUT--I am on thin ice still in my own conscience with the real possibility of catastrophic failure in an exhibition-level structure such as this; and must treat it for now as a remarkable sculpture that may herald the necessary catch-up of principle and practice behind such speculative adventures.  I have a vast new personal confidence in the earthbag system from feeling my way through this process but also thirst for the verifications of controlled quantitative study which may ultimately permit broad adoption.  Sadly, my prior (and very modestly/stably proportioned) earthbag effort sits unfinished in limbo as the case is slowly made to officialdom...now THAt's risky for ya!
A few critical caveats--my works have been basically in line with Kahlili's 'Superadobe' protocol, using tube sack in continuous curvature and cement stabilization around 7% b.v.--features which significantly enhance performance over discreet linear bagging of raw earth (unstabilized soil may accomplish similar load bearing at cure but anxiety quickly rises with future possible water content--anyone done test-to-fail on rewetted pure-earth walls?).  Also climatically, this system is especially suited to warm arid zones and should be peppered with question marks anywhere that confronts chronic moisture or chill.
This should be a link to some photos (work proceeds and a thorough report forthcoming on culmination):  http://www.flickr.com/photos/19483908@N00/sets/72157623089095081/
Bon Chance!

--- On Thu, 1/14/10, coblist-request at deatech.com <coblist-request at deatech.com> wrote:Date: Thu, 14 Jan 2010 09:56:07 -0600
From: <howard at earthandstraw.com>
Subject: Re: [Cob]
 Next step
To: "Janet Standeford" <janet.standeford at gmail.com>,    "Cob List"
    <coblist at deatech.com>
Message-ID: <EA383568BEE7487480BC645DD6228645 at h4howard1>
Content-Type: text/plain;    charset="iso-8859-1"

While the bags may well resist such a load I hope no one is attempting a 20 foot high wall of them as that would be very risky.


Howard Switzer, Architect
668 Hurricane Creek Road
Linden, TN 37096
931-589-6513
www.earthandstraw.com
  ----- Original Message ----- 
  From: Janet Standeford 
  To: Cob List 
  Sent: Wednesday, January 13, 2010 6:39 PM
  Subject: Re: [Cob] Next step


  Hi Damon,
  Actually
 the dirt is dampened and fed into bags already in place on the 
  wall. Coffee cans can be used, then the bags are jiggle tamped. That's 
  actually a lot less work than cob and it provides thermal mass.
   If my calcs are right the 840 kN/m Kathy mentioned is equivalent to 
  188,000 lbs/ft so with a wall only 20 feet high, there is no way the 
  bags can burst due to pressure.
  Also, jiggle tamping damp earth  in the bags should, per some sites I've 
  seen, create a more rammed earth effect after dry.
  If I'm wrong on this please let me know everyone.


  Damon Howell wrote:
  > "Does anyone here think the following is helpful to our 
  > cause?...EARTHBAG HOUSING"
  >
  > I never have come to an understanding of earth bags. What happens when 
  > the bags deteriorate? Hope I'm not around one when that
 happens. I've 
  > watched videos of people doing it and it seems to me cob construction 
  > is about the same amount of work. Plus I feel much safer standing 
  > beside a solid cob wall.
  >
  > Damon in GA, USA
  >
  >
  > _______________________________________________
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  > Coblist at deatech.com
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  >


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------------------------------

Message: 4
Date: Thu, 14 Jan 2010 10:45:36 -0800 (PST)
From: Alessandra <alecaprara at yahoo.com.br>
Subject: [Cob] Eco Hotel
To: COB <coblist at deatech.com>
Message-ID: <29078.68231.qm at web52905.mail.re2.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

Hi everyone!
Many time I just read your messages because I really want to learn a lot about this kind of material. I think I?m here since 2006 or 2007. And now that seed?I've found is getting its first leaf. My coleagues and me
 are?beginning a project of an Eco Hotel. I don't know?if it is the correct term for you, but the idea is a completely?self susteinable hotel using only natural material, mainly COB.?I don't even know if there is some?interest about this subject so I'm here to invite you to give any kind of sugestion or restriction. An information I'm looking for is if there is any hotel you know or heard about that is completely self susteinable. When I joined this?list there was a propose of?prepare workshops?for cob constructions and I don't know if it still exists. We are still writing and developing the idea, but I want to share this with you, because I know you have a lot of experience.

The Hotel will be placed in Sao Paulo state, Brazil and we want to start next semester.
Sorry for the unusual english.

Thanks,

Alessandra Caprara
Consultora e?Adestradora C?o Cidad?o
tel: ?11?34473465? 11?34473465 
Cel: ?11?75471786? 11?75471786
 
email: alecaprara at yahoo.com.br
skype: alecaprara


      ____________________________________________________________________________________
Veja quais s?o os assuntos do momento no Yahoo! +Buscados
http://br.maisbuscados.yahoo.com

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End of Coblist Digest, Vol 8, Issue 13
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