[GSBN] Straw bale survives the recent New Zealand earthquake

Sun Jan 26 15:28:55 UTC 2014

Hi all,

Can't wait to learn more about how this place was put together, (or not).
 We have a debt to the unfortunate owner and the shaky ground of New
Zealand for providing us with a full-scale shake-table test.

One thing that intrigues me is that to me there is a minimal amount of 45
degree shear cracking relative to the size and amount of cracking. Most
cracks shown appear to be at joints and possibly vertical cracks following
posts or something like that, rather than shear, but at the same time I
don't see any indication of areas were there are shear panels, braces, etc.

So many questions!

John

On Sat, Jan 25, 2014 at 3:48 PM, Graeme North <graeme at ecodesign.co.nz>wrote:

> Hi
>
> The only reports of damage I have seen to any other buildings in the area
> are to some chimneys, and lots of items on shelves such as household items,
> and bottle carnage in bottle stores.
> I have seen some photos of ground cracks that would not be healthy if a
> building was on top of that, but have not heard any reports of building
> collapse or anything approaching that. No one was badly hurt.
>
> I would say that the plaster on the strawbale house that has been widely
> reported as failed was cement plaster. In some shots it appears that this
> was separated from the straw by a membrane of some sort. It seems to have
> been the most extensively damaged house in the area, and is therefore
> attracting attention.
>
> My clients' house nearby had lime plasters on it and came through well.
>
> Once we have the property file from the local authority we can report in
> more depth.  PR harm is a very real concern.
>
> This was not a particularly big earthquake and was quite deep, but was
> very widely felt with a reported rolling motion. I have heard it described
> as a tension earthquake where very hard rock is torn apart, rather than the
> more usual fault line or plate slipping ones we commonly get.
> However, it still was of very similar magnitude to the ones that flattened
> Christchurch, but the latter were pretty much direct hits, very shallow,
> and characterised by very severe vertical acceleration.
>
> No wonder NZ is called "the shaky isles"
>
> Cheers
>
> Graeme
>
>
> On 26/01/2014, at 7:18 AM, martin hammer <mfhammer at pacbell.net> wrote:
>
>  Hello all,
>
> Thanks Bruce for providing the link to the news video, and Graeme for the
> reports from your clients.  Good points raised by all.
>
> Many questions and issues come up for me.
>
> Bruce, why do you say "the SB house is standing, when the neighborhood is
> not."?  Are there photos or reports of homes surrounding this SB house that
> have collapsed?
>
> I think the news video *really* makes strawbale look bad, not just "sort
> of".  Between the sizeable cracks and spalled plaster (under the window),
> the reporter's characterization of the damage, and the owner's worried look
> and use of words like "bomb-site" and "unlivable", a viewer's opinion of
> strawbale buildings will certainly be negative.  It reminds me of the
> electrical fire that occurred in the attic of one of the China (Mongolia?)
> SB houses that inappropriately used loose straw as insulation.  This event
> indefinitely harmed SB's reputation there and turned many away from it.  I
> hope that letters to editors, or comparisons to nearby houses that suffered
> more damage, or showing well-built SB houses that suffered little damage
> can help reverse the negative PR.
>
> One would expect cracks in plaster shear walls as they resist a moderate
> to large seismic event.  It's part of how the system absorbs and dissipates
> energy.  But at magnitude 6.2 I'm not sure I would even call this moderate
> (no offense to those who suffered from this earthquake) (*see NZ
> legislation definition of a moderate earthquake below).  By comparison, the
> 2003 San Simeon earthquake, inland from California's central coast, was a
> magnitude 6.5, and Ken Haggard and Turko Semmes reported little or no
> damage to the numerous straw bale buildings they designed or built in the
> area.  Seeing this kind of damage to the building in the video in a lower
> magnitude earthquake leads me to believe its lateral systems was
> under-designed and/or poorly constructed.  (Acknowledging there are many
> relevant variables, including proximity, direction of force, and especially
> geologic conditions at a particular location.)
>
> Questions I have about the house:
>
> Is it load bearing or post & beam with SB infill?  What is the in-plane
> lateral resisting system?  If SB shear walls, what are the connecting
> details (top and bottom plates, mesh attachment).  Is the mesh embedded in
> the plaster?  Does the plaster bond with the straw (wherever there is a
> crack or spalling, I see a sheet material, not straw).
>
> One long-term concern I have about SB buildings in moderate to severe
> earthquakes, is that plasters will likely crack (or exhibit crushing at the
> bottom of the walls), especially for buildings with SB shear walls.  This
> is fine, in that it's how the system works, and in most cases the cracked
> or crushed areas should be repairable, making the building ready to resist
> the next earthquake.  However, my concern is one of perception.  Many
> people, including literally and figuratively shaken owners and occupants
> will see these buildings (and SB) as a failure, or at the minimum their
> confidence will be undermined.  Not sure there's an answer to this, just
> stating a concern.
>
> Martin Hammer
>
> *Earthquake-prone buildings: moderate earthquake defined  (per New
> Zealand Parliamentary legislation)
> . . . moderate earthquake means, in relation to a building, an earthquake
> that would generate shaking at the site of the building that is of the same
> duration as, but that is one-third as strong as, the earthquake shaking
> (determined by normal measures of acceleration, velocity, and displacement)
> that would be used to design a new building at that site.
>
>
>
> On 1/25/14 7:38 AM, "Derek Roff" <derek at unm.edu> wrote:
>
> One of the odd things about the video clip, is that the report focuses
> primarily on "claims".  The announcers begin by talking about the "hundreds
> of lodged claims already", and the on-location reporter begins by saying
> that over 650 claims have been received.  With this journalistic
> orientation, it is not surprising that they featured a badly damaged house,
> and emphasized the problems.  I wonder if the owner's assertion, that the
> house is "unlivable", stems from a desire to have the house replaced,
> rather than repaired.  The segment ends with more discussion of claims, and
> advice on submitting claims.  Not a single mention of injuries, or how nice
> it is that there weren't injuries.  Everything is about property and cost,
> in this report.
>
> As far as the plaster missing below the exterior window, it looks to me
> like there is a fabric of some kind draped from right below the sill beam
> to almost the grade level.  Perhaps this was done for water diversion, but
> it looks like there would be zero connection between the plaster and the
> bales in this area.
>
> Derek
>
> On Jan 24, 2014, at 8:12 PM, Timok33 wrote:
>
> My thoughts exactly Jeff. And the large section that sheeted off bellow
> the window didn't look mechanically bonded at all.
>
> It would be great to see a comparison to other structures nearby but I
> would not call this a success in my book.
>
> Tim
>
> Please excuse brevity and typos as I use my mobile device
>
>
> On Jan 23, 2014, at 4:02 PM, Jeff Ruppert <jeff at odiseanet.com> wrote:
>
> I have to say, after seeing walls that have undergone a lot of stress, the
> plaster on the house in the video looked like it had not been adhered to
> the bales very well.  The one shot showing the chicken wire reminded me of
> our compression tests where the walls with mesh were actually weaker than
> those with mesh (we used chicken wire as well).  On our tests it appeared
> that the plaster was inhibited from being worked into the bales properly
> due to the mesh.
>
> Jeff
>
>
>
> On Jan 23, 2014, at 3:52 PM, Graeme North <graeme at ecodesign.co.nz> wrote:
>
> Hi Folks
>
> I have designed a straw bale house that was near the failed s/bale
> building.  The one that failed I know noting about.
>
> Here is what my clients have to say with a few more personal bits taken
> out:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> *Hi Graeme How are you doing?  I was just thinking of you the other day,
> so thanks for mailing.  We're doing just fine here, and no, we aren't the
> one that had the damage, as you well could have guessed.  That house is not
> far away, we have visited it before, and while it looked lovely, it had a
> very small hat, a butynol roof with sod on top that apparently leaked quite
> a bit before the quake, and cement based plaster that has fallen off all
> oevr the place.  In fact, we got a visit two days ago from the local
> council inspectors who just wanted to see whether our place held up ok,
> straight after they visited the other one.  We suspect that they were
> trying to see if straw, as a rule, was a failed material. Thankfully we
> were able to reassure them  :)   We do have a few minor cracks (it was a
> big shake), just at joins between materials - despite reinforcing the
> joins, I guess that was to be expected.  But nothing we can't fix with a
> few days fiddling around (and thankfully no EQC required... we have no
> insurance anyway  :) ........... take care Kyle *
>
> Hello Graeme,
>
> it is nice to hear from you! I think Kyle has already replied, and so you
> will know that our home performed very well during the quake. kyle was away
> at the time.. I was dumb struck for a while before I registered that it was
> an earthquake..by the time that happened, it was all over. we have a few
> superficial cracks where straw meets wood...otherwise nothing more..several
> glass trinkets and pottery items fell off of shelves and smashed, which
> made a mess, but while pretty, were not overly valuable.
>
> The poor old house that was in the media was built in every way, how straw
> bales should not be built..it hasn't faired well in the wet weather or the
> shakes. I think the  local council have been stressed out about it, and
> unfortunately, the media have made straw bale homes look
> suspect...regardless, we are very happy, safe and warm, and , even if the
> quake flattened our home, we would be happy to shake off the dust, collect
> the recyclable materials, and start again.
>
> .......
> Take care and love to you both
>
> Janet
>
>
> On 24/01/2014, at 1:21 AM, Frank Tettemer <frank at livingsol.com> wrote:
>
> AT exactly 1:00 minute into the video that Bruce linked us to, there is a
> view into the wall, between a wider crack.  It looks a lot like Chicken
> Wire that was used as a plaster lathe.  Isn't chicken wire one of those
> materials, (like rebar stakes), that has evolved over time, to be replaced
> by something less stretchy? Like welded fencing wire, or, Tenax cinteflex
> plastering lathe?   Considering the stretchy nature of chicken wire, I
> posit that the plaster render itself was the active material in absorbing
> the shaking energy.  Kudos to plaster!
> Frank Tettemer
>
> /A straw bale home in Pahiatua succumbed to the quake.The home's plaster
> is split, with cracks visible both inside and out.The occupant, Belinda
> Payton, said she was vacuuming the floor and heard some rumbling. "And the
> floor started shaking and I just ran out the door," she said. "We had a
> look inside and it was just like a bombsite. I was was shocked. It's
> unlivable." <
> http://tvnz.co.nz/national-news/earthquake-claims-roll-in-amid-clean-up-aftershocks-5804294>/
>
> Actually, all the news reports talk about minor damage and no injuries.
> Though one set of commercial buildings would need to be torn down, there
> wasn't a report <
> http://www.stuff.co.nz/national/9629660/Severe-quake-rattles-lower-North-Island>
> of another residence being seriously affected. The Kiwis seem to take 6.3
> in stride:/ "//Pam Lochore, wife of All Blacks great Brian Lochore, said
> photographs had fallen off shelves and "a rugby ball went flying across the
> room" ...." /Not enough to severely interrupt a broadcast of a dog race....
> <http://youtu.be/Fgh3lptxESI>
>
> The damage to the strawbale looks to be much as we anticipate....major
> cracking in the sacrificial stucco but the structure otherwise in tact.  It
> looks horrible, though, and Belinda is clearly shaken, but I don't see
> damage other than plaster cracks--no broken windows or toppled structure.
> The plaster obviously absorbed a great deal of the energy.
>
> John "Rolling Motion" Swearingen
> ............................................................................................................
>
>
> On Tue, Jan 21, 2014 at 3:04 PM, Bruce EBNet <bruce at ecobuildnetwork.org <
> mailto:bruce at ecobuildnetwork.org> <bruce at ecobuildnetwork.org%3E>> wrote:
>
> This TV spot sort of makes it look bad -- but the SB house is standing,
> when the neighborhood is not.  Courtesy of Hugh Morris, with a fancy nod to
> Graeme North.  Any of you Kiwis know which house this is?  Did you build it?
>
> Bruce King
>
>
> http://tvnz.co.nz/national-news/residents-count-cost-north-island-quake-video-5804861
>
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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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