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RE: Any Young Engineers Out There?

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While I agree that as it stands right now (pre-2005 AISC spec), ASD is in
general much simpler to use than LRFD.  But, it is more than just the load
factors, I believe.  There are additional failure mechanisms and "checks"
that are currently in LRFD that have not (until the 2005 AISC spec) made
it into ASD.

When the 2005 AISC combined spec comes into full use, I am not so sure
that there will be such a huge "benefit" to using ASD over LRFD.  The
differences on the capactiy side will go away.  Yes, it will still be
simpler in ASD as you only need to "nominally" do one load calculation for
both strength and sevicibility.  But, I suspect that many may start to see
that as a rather minor "benefit" and I expect that you will seem more of a
transition to LRFD.  The old reason of sticking with ASD (i.e. your boss
knows and uses ASD but you learned LRFD in school) may go away as ASD and
LRFD will largely be identical with very minor differences.  Thus, new
grads could conceivably be taught LRFD in school, do LRFD calcs on the
job, and have their ASD boss (assuming that the boss ain't trying to get
away with using "old" ASD) understand and be able to check the calcs.  The
only unknown while be how schools "teach" it.  Technically, they will be
teaching LRFD _AND_ ASD at the same time.


Adrian, MI

On Tue, 24 Jan 2006, Wesley Werner wrote:

> Mike,
>     Since the 13th edition of the steel manual uses both a form of ASD
> and LRFD, I expect ASD will remain for longer than 15 years. Especially
> since serviceability checks are done with service loads. This makes
> steel design much simpler using ASD. I wish ACI was set up the way the
> new steel manual is.  Then I could use ASD for steel design, footing
> design, and soil bearing checks.
> Wesley C. Werner
> -----Original Message-----
> From: Mlcse(--nospam--at) [mailto:Mlcse(--nospam--at)]
> Sent: Tuesday, January 24, 2006 2:11 PM
> To: seaint(--nospam--at)
> Subject: Re: Any Young Engineers Out There?
> Bill,
> I think it took about 30 years to change from working stress in concrete
> to strength design, so it will take just as long for LRFD in steel..
> LRFD has been around for about 15 years or so in the design community,
> so probably another 15 years or so and everyone will be using just LRFD.
> Mike Cochran S.E. SECB
> In a message dated 1/24/2006 10:33:07 AM Pacific Standard Time,
> BPolhemus(--nospam--at) writes:
> 	Here's the question that I want to see answered...and mark my
> words, it
> 	will probably be asked before a year has gone by:
> 	"How many engineers here--regardless of age--took one look at
> the new
> 	Thirteenth Edition AISC Manual of Steel Construction, put it up
> on their
> 	bookshelves and went right back to the Ninth Edition?"
> 	(N.B. It's gonna take forty years traveling in the wilderness,
> like
> 	Moses and the children of Israel, before the last vestiges of
> the ASD
> 	Idolatry are snuffed out).

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