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RE: Diaphragm Chords

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I will generally use 1/2 the nominal joist spacing for my space from the
last joist to the wall.  I too like to weld the deck to an angle with the
angle welded to embed plates.
 
This rule generally allows the deck to work in compression for the out of
plane loads and allows the joist to deflect differentially to the wall.  It
also works out that an iron worker standing on the deck can fasten the deck
to the joist and angle while strategically shifting his weight.
 
Regards,
Harold Sprague
The Neenan Company 
harold.sprague(--nospam--at)neenan.com <mailto:harold.sprague(--nospam--at)neenan.com>  
 

-----Original Message-----
From: Jim Kestner [mailto:jkestner(--nospam--at)somervilleinc.com]
Sent: Wednesday, December 02, 1998 4:45 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Diaphragm Chords


  

Robert Rollo wrote: 


  

	.  [Robert Rollo]  I believe you are right.  The first joist in from
the short wall 
(parallel to the short wall) probably works as the chord  in the other 
direction. [Robert Rollo]   as a matter of fact, i have had respected
engineers tell me that they used to place the first joist as colse as
practical (6") from that wall for this exact reason, not to induce much
horzontal bending into the top of the wall ! 


The only problem with putting the first joist so close to the wall is how to
close off the roof  with a cambered joist and a level wall (gravel stop
condition). You would not have this problem with a parapet. I prefer to have
the joist several feet away and have an angle bolted to the wall or an
embedded plate in the bond beam that the deck gets welded to. 

Jim Kestner