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RE: New LFRD/ASD Steel Code (Was: Any Young Engineers Out There?)

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I agree with most of what Scott has written below, but I have a little
different viewpoint regarding the "legality" of using working stress
design (WSD) for concrete design.  I do agree that technically the
Commentary is not part of the legal document, so disagreements on its
use are quite possible.  But I also feel that a reasonable argument can
be made that the same ACI committee members that wrote the code
provisions also wrote the commentary to the code.  Thus the commentary
does represent their "intent", even if the code is not so clear.  It
would seem that using WSD per the 1999 methods would still meet the
"standard of care". 

As suggested by Scott, ACI 350 has retained the Alternate Design Method
in an Appendix, including in the 2006 version of the ACI 350 code soon
to be published.  


William C. Sherman, PE
(Bill Sherman)
CDM, Denver, CO
Phone: 303-298-1311
Fax: 303-293-8236
email: shermanwc(--nospam--at)cdm.com

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu] 
Sent: Tuesday, January 24, 2006 3:53 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: Any Young Engineers Out There?

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."

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