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Re: Wood framed walls

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At 00:53 8/14/97 -0400, you wrote:
>In a message dated 97-08-13 16:28:24 EDT, Michael Cochran writes:

>Subj:	Wood framed walls
> ....  Currently the >allowable design value for gypboard is 30#/foot in
Los Angeles City because of the poor performance during the Northridge >
earthquake.  In my opinion the allowable design value for gypboard should
be zero.  

> The only testing of stucco walls I have heard of was done years ago and
was monotonic testing only.   I don't think anyone has published any 
>  information in dynamic testing of stud walls with stucco.  ...

[Bill Cain, SE]  I observed (from outside the perimeter fencing that had
been set up) the apartment building that collapsed in the Northridge EQ.
It appeared that the first floor walls consisted solely of the stucco
system applied directly to the studs without any sheathing (Maybe those who
got a closer look can verify if this was the case) and probably gypboard on
the interior.  ONCE THE STUCCO (and gypboard) BREAKS (on the first major
cycle), THERE IS ZERO LATERAL STRENGTH LEFT AND PEOPLE DIE.  It should be a
"no-brainer" to anyone in an area where there is a possibility of an
earthquake happening (and I mean not just Zone 4) that stucco is a
dangerous material to rely on for lateral resistance.  I wood extend
Michael's conclusion regarding what the allowable design value for gypboard
should be to stucco as well (i.e., zero).  


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BILL CAIN, SE
OAKLAND, CA
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