[GSBN] Straw bale survives the recent New Zealand earthquake

[John Swearingen]

Thanks, Graeme.  We look forward to your first-hand inspection!

>From what you noted, there was no tie beam or foundation holding together
the "ground embedded posts".  If that's indeed the case, then as the
rolling waves passed through the house, the posts would have swayed
independently,like boats' masts in a marina. This would be an eccentric
movement that the straps may not have been able to effectively restrain.

John "Mastadon" Swearingen


On Thu, Feb 6, 2014 at 1:17 PM, Graeme North <graeme at ecodesign.co.nz> wrote:

> Hi Everyone  - A very preliminary report:
>
> Ian and I have now reviewed the council file on the damaged strawbale
> building and can report so far that:
>
> 1) The drawings are rudimentary and show little construction detail but
> they do show the roof held up on timber beams, supported on a series of
> ground-embedded posts. Lateral bracing is from crossed and tensioned metal
> straps so the plaster skins were not expected to take lateral in-plane
> loads - or not intentionally anyway.
> 2) The drawings for the  walls show an exterior weather protecting cavity.
> We have no evidence that these were installed from the photos we have seen
> so far.
> 3) There is an earth roof drawn at 100mm thick over a rubber membrane on
> plywood  - presumably the ply roof gave some diaphragm effect.
> 4) The heavy roof appears to have survived the earthquake but we surmise
> that the structure has flexed quite a lot in the earthquake with that heavy
> roof, and this may have induced the severe plaster damage that we have seen
>  so far.
> 5) The drawings show an earth floor - we have no idea yet how this has
> feared.
> 6) We have been told via the grapevine that the building already had
> moisture issues but whether that was roof or walls, or had any bearing on
> the earthquake damage seen we do not know yet.   The Council file is silent
> on that matter as far as we are concerned.
> 7) The drawings were given a building consent in 2003 and the building was
> signed off as being code compliant by the Council in 2005.
> 8) We are willing to travel and inspect the building, but we first need
> relevant permissions unless we go in a very unofficial capacity.
>
> Cheers
>
> Graeme
>
>
>
> On 27/01/2014, at 2:21 PM, Lance Kairl <sabale at bigpond.com> wrote:
>
>
> Hi all
> My two bobs worth.
>
> To me it looks like a post and beam structure with the posts in the centre
> of the wall, Perhaps with Only straw as the bracing ,  render skins in that
> case would only partially absorb forces!
> In the shake it would compress the straw on one side and then the other as
> it sways, creating stresses further along the walls,
> And with any oscillation of the posts result in a vertical crack in the
> render adjacent to the post.
>
> Note crap window sill / render detail .
> I'm glad we don't build them like that, and don't have 6.5 + quakes to
> deal with.
>
> Like many of us would love to be there to inspect and learn.
> Cheers lance.
>
>
>
>
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-- 
John Swearingen
Skillful Means Design & Construction
2550 9th Street   Suite 209A
Berkeley, CA   94710
510.849.1800 phone
510.849.1900 fax

Web Site:  http://www.skillful-means.com
Blog:         https://skillfulmeansdesign.wordpress.com
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