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GSBN: Digest for 3/4/02

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-> re: Re: GSBN:re: [paille] Contreventemnt maison paille
     by Andre de Bouter m.ep@...
-> Re: GSBN:re: [paille] Contreventemnt maison paille
     by bruce king ecobruce@...
-> RE: GSBN:re: [paille] Contreventemnt maison paille
     by "Martin Oehlmann" martin.oehlmann@...


Date: 4 Mar 2002 06:33:04 -0600
From: Andre de Bouter m.ep@...
Subject: re: Re: GSBN:re: [paille] Contreventemnt maison paille

Dear Chris and Jeff,

Thanks for your input. Do you have contact addresses?

> Kris Dick, of the University of Manitoba,

> The EBNet Conference CD-ROM has a good article, Straw Bale Shear Wall
> Lateral Load Test, California Polytechnic State University, December, 2000,
> By Jason Nichols &Stan Raap, which may be of help to you too.

Since I'm no engineer I've always wondered when we do or don't need to add
extra cross bracing. Loadbearing SB walls have cross bracing capacities
because if they did not there would not be Nebraska SB homes, but how much of
the cross bracing of the straw can be utilized in a post and beam structure?
Sure, we can always add extra cross bracing, but as always I'm hesitant to do
so before I feel sure it is needed.

I'm contemplating launching an effort to get SB accepted by the French
building codes. Known here as the CSTB.
For that I would like to start with a 100 m2 (roughly 1000 sqft) model SB
home, trusses + light post and beam with a screw down method as used by the
But before we start shopping for subventions to finance a program to pass the
CSTB I would like to be sure about this cross bracing thing. Then again, we
could start of with some numbers from the tests or your gestimates and then
have tests done here in France. 

In April I'll be going to Brussels, home of the European Union to see if
anything can be done on a European level, rather than country per country. 

Suggestions and advice or other help are always welcome!

Greetings from a cool but lovely sunny day in France,

La Maison en Paille
Habitat Eco-Logique 

Andre & Coralie de Bouter
Le Trezidoux
16290 Champmillon
Charente, France 
Tel. (0)5 45 66 27 68 



Date: 4 Mar 2002 08:47:52 -0600
From: bruce king ecobruce@...
Subject: Re: GSBN:re: [paille] Contreventemnt maison paille

Jeff Ruppert wrote:

> The test report that Chris mention, fom Cal Poly, is the best one to date.
> The walls failed at over 4000 pounds per linear foot.

Everyone needs to know and understand that those were very special walls.
They didn't just have cement-based plaster, but had very special edge
connections for the heavy mesh -- bolt heads at four inches on center
projecting above the wood frame (and into the plaster), and lots of staples.
They were, in other words, designed to be super-strong walls, and do NOT
mimic what people usually build.

An ordinary cement-plastered wall with light mesh will break at 1200 to 1500
pounds per linear foot;  most engineers would apply a safety factor of four
and use, say, 300 pounds per linear foot.  That is exactly what we are about
to get codified in California.

If you're not in a seismic area, you could probably use a higher number
(like 500 plf), because wind is not as hard on walls as earthquakes are.
But then, if you don't have earthquakes, you won't need much strength.

greetings to all from sunny, flowery California in Spring,

Bruce King

PS:  the straw bale testing program, after a lot of fussing about, is
finally getting into gear.  Sometime in the next few weeks I will write an
update on what tests we'll be doing, and post that to the EBNet website
(www.ecobuildnetwork.org), and send a copy to The Last Straw.


Date: 4 Mar 2002 16:11:53 -0600
From: "Martin Oehlmann" martin.oehlmann@...
Subject: RE: GSBN:re: [paille] Contreventemnt maison paille

Bonjour Andre - Simon,

pre-compressing the top-plate with 5t-belts works well for compact walls.
Hitting the walls, they will "sing", the soundwaves move through the wall.
With loose bales you don't receive that quality, something the French
engineers might be afraid of. Attaching the top-plate at the post and beam
structure keeps the walls compact. Than you can remove the compression
belts. Results: less airgaps, easier shaving and less stucco. The Ouwerkerk
house matched easily 8 tons windloads and performance of even more compact
walls have improved since than.

Attractive and easy comprehensible is also Tom Rijvens system: post -
strawbale - post - etc. screwing a bar between the posts to keep the
strawbale on spot, cut the strings and continue...

Jan Steenks and myself tried strings instead of a bar which works well too
and in a different form: post - strawbale - post - etc + precompression on
the total length of the wall which works excitingly well. If Simons
engineers are interested in exchange of experiences, detailed plans would be
appreciated. Bracing or not depends on the design and the choosen technique.

If you think in terms of pre-fab elements you might get in touch with
Herbert Gruber.

Salut, Martin Oehlmann

Werkgroep Strobouw Den Haag

- -----Oorspronkelijk bericht-----
Van: GSBN [mailto:GSBN@...]Namens m.ep@...
Verzonden: donderdag 28 februari 2002 14:15
Aan: paille-l@eyfa.org; GSBN
Onderwerp: GSBN:re: [paille] Contreventemnt maison paille

Bonjour Samuel,
Je passe tes questions aux reseau mondial de Constr en Ballots de paille.
Corrige moi si mon traduction n'est pas correct.

and Hi GSBN

Samuel Cougey, an active SB and hemp builder/teacher here in France has a
few questions concerning bracing SB walls. Samuel is getting into a project
where the engineers want to see some bracing other than the SB. They want to
work with a sort of prefabricated system. Samuels' engineers questions are:
Do we have a system of bracing with tension cables-wires
Do we have a system of bracing by the internal panels

Personably I would like to add:
What do we know (in technical detail) about the crossbracing capacity of SB
so we can at least try to persuade the engineers we don't need any
additional bracing. Within what limits
can the SB do the work? We are talking post and beam, not loadbearing.

You will find the orriginal french message below

> Pagnoz, Jura, le 25.02.2002
> A l'origine d'un double projet exp#233#rimental bois/paille et bois/chanvre
> sera suivit par des scientifiques fran#231#ais dans le but de mieux
> ces techniques, nous cherchons #224# g#233#rer le contreventement de la
> paille.
> Si en auto-construction (ou g#233#rer directement par un charpentier), cela
> nous pose pas de gros soucis, sur un projet regard#233# et dissequ#233# par
> tas d'ing#233#nieurs, il faut une solution logique pour les calculs, et,
> facilement reproductible.
> Un premier syst#232#me type poteaux/poutres a #233#t#233# propos#233# par un
> d'ing#233#nieurie suisse mais il est lourd et couteux. Pour proposer une
> alternative, des retours d'exepiences me serait d'un grand recour:
> -Avez vous des exemples de contreventements par cables tendus?
> -Avez vous des exemples de contreventements par panneaux int#233#rieurs?
> La fili#232#re bois locale s'int#233#resse au projet mais souhaite qu'on lui
> un syst#232#me plus pr#233#fabricable. Avez vous des exp#233#riences ou
> des exemples ou photos de panneaux bois/paille pr#233#fabriqu#233#s?
> Merci d'avance
> Samuel COURGEY

>** --------- End Original Message ----------- **


La Maison en Paille
Habitat Eco-Logique

Andre & Coralie de Bouter
Le Trezidoux
16290 Champmillon
Charente, France
Tel. (0)5 45 66 27 68


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