Yoshihiro Takishita describes how the massive, timberframed "gassho zukuri" houses of Japan withstood tremors and storms--in which "the roof may become deformed or shift slightly, but...It resettles naturally, since the tenons are forced back into their mortises by the weight of the roof itself."* Major beams were often selected from twisted and crooked trunks, to take advantage of natural curves that were employed to enhance stability. This observation, however, hardly seems applicable to stud and joist construction.<br>
<br>Nevertheless, Hugh Newell Jacobsen, an architect with a long and carefully considered career in residential design, commented on how many vintage homes in South Carolina withstood Hurricane Hugo, while new ones "literally exploded." <br>
<br>"That is primarily because corners and rafters are just butt nailed, with little to hold them except good intentions. There's no diagonal, no strapping, nothing to firmly hold. And even with the technical design of plywood skin to reduce torque and rack, <u>you can't wrap corners with it.</u>"** [emphasis added]<br>
<br>By the same token, I recall photos of Galveston following the recent devastating hurricane--showing near complete destruction of block after block of residential neighborhoods, punctuated by the occasional surviving house--which uniformly looked like construction subsequent to adoption of wind resistant building codes. This tends to validate Jacobsen, in that connections between roof, floor, and wall assemblies had been taken into consideration, resolving the essential flaw he identified.<br>
<br>All this to say that there is no place for an intermediate position--that if we are building plywood skinned platform framed buildings--that we need to follow all the way through with best practices or engineering for our connections. <br>
<br>AA<br> <br>*Japanese Country Style: Putting New Life Into Old Houses/Kodansha<br>**The Wood Book 1990/Hatton Brown<br><br><br clear="all"><b style="color:rgb(0, 102, 0)">Alan Abrams</b><b style="color:rgb(0, 102, 0)"><br>
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<br><br><div class="gmail_quote">On Sun, Jun 5, 2011 at 12:31 PM, Kat <span dir="ltr"><<a href="mailto:molasses@q.com">molasses@q.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div bgcolor="#ffffff" text="#000000">
I'd stick to the code. It was revised/became more stringent after the
Kobe earthquake and will probably change again in a few years based on
analysis of the most recent earthquake.<br>
<br>
I've heard that ancient Chinese structures survived earthquakes because
they were built without fasteners of any kind - my (non-engineer)
understanding of that is the jiggling distributed itself throughout the
structure at the joints, which were sort of lincoln-logged together. I
think the key there is NO fasteners, though. None. I'm certain that
if you build a house the way we do now (all full of nails) and neglect
to attach it to the foundation and we get a big earthquake you'll end
up with a house that slides off the foundation.<br>
<br>
-Kat<br></div></blockquote></div><br>