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APA EWS PRI 400 Wood Joists

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At the SEAoT dinner meeting in Dallas last night, the presentation was
made by APA - The Engineered Wood Association and the topic was their
new (since 7/4/97) Standard PRI 400 for Performance Rated Wood I-Joists.
 I left the meeting with three troubling questions which the speaker did
not adequately address:

1.	The joists are being promoted, in part, upon their ability to provide
relatively long spans (up to 60 feet).  Nevertheless, the joists are
manufactured with absolutely no camber or crown.  There is no defined
top and bottom.  Won't deflection be a significant problem?

2.	Each joist is sent to the jobsite with a complete table of allowable
spacing and span (simple and continuous) combinations printed boldly on
the web.  However, the design live loads and total loads are not defined
anywhere.  According to the speaker, carpenters love this because the
joists come with "all the instructions they need".  He also said that
building inspectors love it because they can effortlessly determine if a
joist has proper span and spacing.  My question is, what happens when
the joist is used for the floor of an assembly area or a warehouse?  At
times like this, I almost wish that I was a product liability lawyer!

3.	Based on the entirety of the presentation that I heard, there was no
mention of structural engineering.  In this scenario, what is the role
(if any) of the structural engineer?  While this is not much of a
concern in Texas, I am under the impression that many of the readers of
this list derive much of their income designing houses and apartments in
wood.  I look forward to your comments.

Stan R. Caldwell, P.E.
Dallas, Texas

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Just because you're growing older,
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                                      ... anonymous
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