[GSBN] Catalan vaults

Tue Dec 13 00:08:55 UTC 2011

Very well put, Derek, and I completely agree.  I've been following  
this thread and mulling on the skill required to set thin bricks or  
tiles without falsework in a way that gives a safe (and heavy) roof  
overhead.  Even a slight deviation from perfect geometry will hugely  
raise the risk of collapse, and I'll bet there have been plenty of  
failures, both modern and historic, of such structures that weren't  
quite right.

Similar problem:  Haitians are now hugely averse to sleeping under  
concrete floors or roofs because so many of the inherently flawed  
structures they built before the earthquake came down, and hard.     
Any time you're putting weight overhead, you want to be super  
careful.  (Duh.)

I wouldn't try a Catalan dome of unfired earth bricks for anything but  
the smallest spans, and then with lots of other redundancies.   
Compressed earth blocks maybe a little bigger, but not much.

All that said, they sure are beautiful, and elegantly solve the desert- 
dwellers problem of creating roof spans without any lumber or other  
unbendable beam thingies.    Can't wait to some day visit Auroville  
and see all that famous great work.

Thanks,

Bruce "the Thingie" King

On Dec 12, 2011, at 3:31 PM, Derek Roff wrote:

> It's great to see what people are doing with thin, low-arch vaults  
> and domes.  Obviously things are working for them.  However, I am  
> concerned about safety.  With every building material and design, as  
> we push toward the extremes, the risk of failure increases.  And  
> when failures occur, they are more likely to be catastrophic.   
> Traditional building forms, methods, and materials tend to have a  
> lot of redundancy, and are usually quite fault tolerant.  More  
> modern, optimized, resource minimizing designs and structures  
> require everything to be done right, and run the risk of collapse  
> from the failure of one or a few key elements.
>
> I feel concern about the Catalan arches in this regard.  Individual  
> pieces of the arch are each in high stress.  The perimeter of the  
> low-arch shell experiences forces many times the weight of the  
> dome.  Small horizontal displacements can lead to structural failure  
> and collapse across some or all of the dome.  Few of us have trained  
> our intuitions sufficiently to make accurate judgements about many  
> of the design and building details.
>
> I'm not suggesting that no one should experiment with these  
> structures,  Rather, I am calling for us to take proportionately  
> greater care and to pay substantially greater attention to design,  
> materials, and construction details, when the risks are higher and  
> harder to judge.  I wonder if Bruce, or other engineers on the list,  
> would comment on building Catalan domes with unfired earthen  
> materials.
>
> Trying to keep our heads in the clouds, and out from under the bricks,
>
> Derelict
>
> Derek Roff
> derek at unm.edu
>
>
> On Dec 12, 2011, at 12:02 PM, huffnpuff at q.com wrote:
>
>> Chris and All,
>>
>> I do remember perusing the info posted for the Catalan vaults and  
>> found it most interesting. About a year ago I had an opportunity to  
>> attend a charrette on Compressed Earth Blocks, hosted by Bernard  
>> Amadei at the U. of Colorado. These CEB builders were meeting to  
>> discuss similar issues that we SB builder types are/have  
>> experienced with acceptance, testing, codes etc. Two fellows of  
>> particular vision and spirit were Satprem Maini from the Auroville  
>> Institute, India http://www.earth-auroville.com/vaulted_structures_introduction_en.php 
>>  and Jim Hallock, of icatis, USA http://www.icatis.org/, both NGO's  
>> building with CEB's and Vaults/domes. Both web sites are full of  
>> the work these two organizations have done and are eye candy for  
>> anyone interested in vaults. If you visit the icatis site you'll  
>> see they have teamed with George Nez and built at least one of his  
>> 'thin shelled latex concrete' roof systems.
>>
>> Currently our local engineer and COSBA member Ian Smith and his  
>> wife (both engineers) are on their honeymoon in India at the  
>> Auroville Institute at a workshop on vaults. That's devotion...
>>
>> Mark Schueneman
>> COSBA
>>
>>
>> ----- Original Message -----
>> From: "Chris Magwood" <chris at chrismagwood.ca>
>> To: "with public archives) Global Straw Building Network (private" <GSBN at greenbuilder.com 
>> >
>> Sent: Sunday, December 11, 2011 9:55:05 AM
>> Subject: [GSBN] Catalan vaults
>>
>> Hi all,
>>
>> The mention on this list some months back about Catalan vaults (or
>> Guastavino vaults) sparked my interest, and we've now decided to  
>> forge
>> ahead and build one as the roof for a buried, earthbag root cellar at
>> Trent University.
>>
>> Does anybody have experience building these, or know of anybody who
>> does. I'd like to try and hire in somebody to lead us in this build.
>> It's a small structure (18 x 22 ft) so it won't be a long build,  
>> but I
>> always like to have someone knowledgeable in charge when doing  
>> things I
>> haven't done before.
>>
>> The budget for the project is not high, but I would be willing to try
>> and cover travel costs, food, lodging and a bit of cash for the right
>> person.
>>
>> Let me know!
>>
>> Chris
>>
>> -- 
>> www.chrismagwood.ca
>> www.endeavourcentre.org
>
>
>
>
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