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RE: Wood Allowable Stresses

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Sounds to me like you're doing the right thing... checking your judgment
call when there's no clear answer.

Here are some suggestions/comments:

1.	Make sure you get enough sleep at night.
2.	It's always the engineers job to make things simple and
understandable. There are however ways to help the owner appreciate the
complexity of what you may be struggling with by refining what they
want. Architects refer to this as the program definition. It's hard to
help effectively sometimes if you can't see the questions trying to be
answered. Perhaps a quick lesson in "how much confidence do you want in
my answer" will help ferret out an appreciation for how you need to
answer the "simple" question.
3.	It is always right to question changes in the building code.
Changes for better and for worst should be understood and appreciated.
We don't always have the time to figure out why a change has happened,
but with resources such as this list, we can oftentimes get there
quicker.
4.	Don't assume that a simplified analysis will tell the truth.
Listen to the wood!? Sometimes "if it ain't broke, don't fix it" can
help us look for other ways gravity laughs at our calculations.

The wood stress downgrading issue deserves a thorough reading. Perhaps
others on the list will have some quicker suggestions on where to go to
get additional information here.

And lastly, it didn't really make any difference to me which boss you
were referring to. They both are well qualified and fit the mould.

Barry H. Welliver
barrywelliver2(--nospam--at)earthlink.net
 

-----Original Message-----
From: Jake Watson [mailto:jwatson(--nospam--at)utahisp.com] 
Sent: Thursday, July 25, 2002 4:31 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: Wood Allowable Stresses

Thanks for your comments.  We are lucky enough to be evaluating the
condition and are not required to comply with any code.  The evaluation
program was implemented voluntarily.  That said, I still have a "sleep"
issue with telling an owner that 150% of 1900 psi is "OK".  I have a lot
of
conditions where the bending stress exceeds 2500 psi due to snow drift.
The
owner simply wants to know if they need to fix it or not.  They don't
care
about stress changes and the like.

The wood stresses were likely downgraded for very good reasons.  Just
because we as engineers were using a lower factor of safety (I know even
that is arguable) 20 years ago doesn't mean we should perpetuate the
mistake.  That said, there are no visible signs of distress in the
elements
and they have been there for almost 30 years.  It may be that the wood
knows
more about stress than I do!  We ultimately are recommending that the
parapets be removed, although the final decision is being left to the
owner.

It would still be nice to know how much of the stress change is
attributed
to using full size samples and how much is from using new growth wood.

Thanks again for your comments,

Jake Watson, P.E.
Salt Lake City, UT

P.S. Barry,
	I thought I should tell you this is Eric's job and not Kelly's.


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