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RE: Any Young Engineers Out There?

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Bill,

I doubt that you will see such in this case.  In the case of concrete
design (ACI 318), they were really trying to make working stress the
bastard, step child of concrete design if not eliminate it.  And while
they may have wanted it to go "bye-bye", working stress was still a
perfectly "legal" and acceptable alternative as it was put into a
perfectly "legal" (from the point of view of whether you could use it or
not) form in an appendix...that is until the ACI 318-02, which got rid of
the working stress (aka alternative design) appendix.

Now, the commentray of ACI 318-02 in section R1.1 does state: "The
Alternative Design Method of the 1999 code may be used in place of
applicable sections for the 2002 code."  Now, while I am not lawyer (which
if true would likely make you dislike me more than just our differences of
political views), I believe this statement in the commentary has about as
much "force" (i.e. legally applicable) as if I told you it was perfectly
legal for you to drive 150 mph in a 55 mph zone.  Commentarys are
non-mandatory documents and thus are _NOT_ part of the code.  As such, a
code official in a jurisdiction that uses the 2003 IBC (and thus the
ACI 318-02) would be perfectly within his/her right to not permit someone
to use the Alternative Design Method for a building.  I will note,
however, that I believe that ACI 350 (the "water tank" code) does still
have provisions in it for "working stress" design...thus, there are
technically situations where working stress could "legally" be done.

Now, the situation will be different in steel.  ASD is _NOT_ being
eliminated or even reduced to a bastard, step child.  AISC tried to do
that (so to speak) and lost the battle.  They have "surrendered" and ASD
will live (and does live in 2005 spec).  But, it will no longer be our
"parent's" ASD, so to speak.  We get a nice updated version that is
virtually no different from the LRFD "flavor" at least on the capacity
side of the equation.   And I highly doubt that there will be "wording" in
the model building codes that allow the use of "older" ASD specs.

To reinforce that last point, in general when the NDS updates the wood
code (ASD) or ACI updates the strength method of concrete design (with the
major exception of the change in load factors and going to the Unified
Design Method in the main body of the code...both of which are not really
the same situation as what I am talking about), do you see provisions in
the model building codes (or the material standards themselves) that say
"if you don't like the changes that we made to these methods, feel free to
just ignore them and keep using what you have been using"?  The point is
that steel ASD as a method is not being eliminated (or "diminished")...it
will still be there, but they updated it.  As such, I highly doubt that
there will be an "out" that will allow use of the "old" ASD spec.

Now, how well code officials/jurisdictions will enforce the use of the new
ASD specs remains to be seen.  I have no doubt that there will be plenty
of jurisdictions where they will not enforce the use of the spec let alone
even know what the differences actually are.

Regards,

Scott
Adrian, MI


On Tue, 24 Jan 2006, Polhemus, Bill wrote:

> BUT...
>
> Expect to see wording in the codes allowing use of the "older" ASD
> method, much as ACI 318 carried "working stress" design of concrete in
> an appendix for a very long time.
>
> Remember that codes are consensus documents. For "consensus" read
> "political."
>
> -----Original Message-----
> From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
> Sent: Tuesday, January 24, 2006 1:53 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: Any Young Engineers Out There?
>
> Ya, but they will be taking it off that shelf in the not so distant
> future.  This difference this time is that future model building codes
> (i.e. starting with 2006 IBC, I believe) will not longer reference the
> 1989 AISC ASD spec as "permitted"/"legal" design.
>
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