To: "SEAOC Newsletter" <seaint(--nospam--at)seaint.org>
Subject: Re: Something That Bugs Me About The AISC Code
From: Christopher Wright <chrisw(--nospam--at)skypoint.com>
Date: Tue, 15 May 01 22:17:51 -0500
>The AISC Code (ASD or LRFD) goes out of its way to define itself legally as
>a code for "design of buildings." NOTE: Not "Buildings and other
>structures," but simply "Buildings." And the Code doesn't define the word
>"building," interestingly enough.
I don't understand what the problem is. Are you upset with the code
itself or with the semantics of the scope? What difference would it make
if the AISC had a set piece definition of 'building' or a specific number
of recurrences needed to distinguish frequent from infrequent? Would it
>That's the thing: If something were to happen to one of these covers (it
>would only take one, I think) how do I justify my design approach, if I base
>it on AISC which is "for buildings"?
This may come a a big shock, but the AISC Code is used for all sorts of
lifting equipment and has been included bodily in the ASME Nuclear Code
for designing supporting structures. The scope has been widened to
include ferrous materials other than carbon steel. The stress and load
analysis principles are applicable to an even wider variety of steel
applications. I justify using the steel code for all sorts of
non-building frames structures, simply by analogy. A framed support for a
piece of food processing machinery responds to load like the frames in a
warehouse--load paths are load paths. Where there are differences,
notably in stiffness and vibration requirements, I use what's there and
use the intent of the AISC code to cover what isn't stated specifically.
Engineers do that every time they come up with something new.
>How is our litigious society disposed to view my "right" as an engineer to
>use my "engineering judgement" to effect a solution to such an "INFREQUENTLY
>ENCOUNTERED PROBLEM"? Especially if I'm wrong?
If you're wrong, it's pretty easy--you do what Le Mesurier did; namely,
admit culpability and fix the problem. If you're right, your judgement
speaks for itself. Our rights to use 'engineering judgement' are pretty
much circumscribed by our obligation to act in the public interest and to
practice in accordance with proven technical principles.
I can't get over the feeling that there's more to your post than a couple
of quibbles over the scope of the AISC code. Wonder if it's the
realization that LRFD isn't the ultimate answer to the universe and
Christopher Wright P.E. |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)
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