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Re: GSBN: Wind loads and racking
- To: GSBN GSBN@...
- Subject: Re: GSBN: Wind loads and racking
- From: Martin Hammer mfhammer@...
- Date: Thu, 07 Jun 2007 09:03:59 -0700
- Reply-to: "GSBN" GSBN@...
- Sender: "GSBN" GSBN@...
> Bruce King wrote:
>> If it can be yanked out (or in), i.e., away
>> from the plane of the plaster, then it's doing you no good.
> This seems to point to a crucial flaw in the wire-tie proposal?
Andrew, I agree. I think if one uses through-ties, they need to be attached
to mesh, or the ties need to turn substantially up and/or down into the
plaster to engage it. (This is also my answer to Chris Magwood's question
about through-ties without mesh.)
By the way, re: your other question about mesh. In California we typically
use 2"x2"x14 gauge galvanized welded wire mesh in cement, cement-lime, or
lime plasters, and 2x2 polypropylene mesh in clay or lime plasters, or
occasionally no mesh for small non-loadbearing buildings. In Pakistan
Darcey Donovan and I are trying to use only clay plasters and are using
chopped straw reinforcement and external bamboo pins, or fishing net and no
pins. Both California and northern Pakistan are subject to large magnitude
I'm grappling with this whole issue of through-ties (grasping at straws if
you will) to fully understand/explain it. But generally I don't see the
point of through-ties without mesh. And I don't believe through-ties are
necessary at all except in extreme circumstances. Later today I will see
Kevin Donahue (structural engineer who conducted EBNet's out-of-plane tests)
and will pass on any insight I obtain from him.
But to put this in some kind of grounded perspective, has anyone ever seen a
structural failure, or even just plaster cracks, which they could attribute
to out-of-plane wind or seismic loads on a plastered straw bale wall?
Including walls with no through ties and no mesh?
If a hurricane, cyclone, or "the big one" is a possibility, then the
building should be designed for it, whatever that might mean. But I don't
think we need to make our buildings stronger for its own sake. We only need
to make them strong enough . . .