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Re: Some of the Strangest Codes I've seen

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Al,
That was my phrasing, not the codes. It does not state, but rather implies, 
the intention of the code to bring the perfomance of each shear resisting 
element into a similar state of stiffness. In reality this would be very 
difficult to control in the field as it would require all wall which are not 
of the same aspect ratio to be deisigned individually so as to match a common 
stiffness. In my opinion there are few things that can be done with plywood 
shear walls and these include changing the size or spacing of the nails, or 
adjusting the thickness and type of sheathing as well as the number of side 
applied to. In addition to this, the designer can "tweak" out the tension and 
compression chords of the wall for deflection. But to be realistic, how many 
low paid laborers hired by subcontractors who install sheathing take the time 
and effort to insure that the nails are spaced exactly as specified on the 
plan? From my experience - almost none. On every project that I have worked, 
you can be sure that almost every wall panel will be nailed as indicated on 
the plans AND CLOSER. This means that if the plans call for 6"  on center at 
the edges, the panel will be nailed 3", 4" and 6" scattered (and a few at 
8"). The reality is cost of productivity and no contractor that I am aware of 
will opt to lose time and insure the appropriate nail spacing - he would 
simply rather add more. This, as you know, will change the stiffness of the 
wall and throw off our calculations or performance expectations. However, my 
opinion is that it is negligable, but the latest and greatest codes are 
designed for the perfect world.

Dennis

In a message dated 7/21/99 8:56:18 AM Pacific Daylight Time, 
AGrathwol(--nospam--at)BoyleEngineering.com writes:

<< "As close as possible" is a terrible phrase to use if that's the language 
in
 the code. Since anything is "possible", that means you (and the architect)
 should do whatever it takes to make the stiffnesses identical!!  It's an
 awful phrase to use!  
 ICBO lost their nut when they did this code (IMHO).
 Al >>