9th - ASD Only
10th - 1st Ed LRFD Only
11th - 2nd Ed LRFD Only
12th - 3rd Ed LRFD Only
13th - Combined ASD and LRFD
The primary issue, is significant changes in the Specification for Structural Steel Buildings. 1989, 1993, 1999, 2005 And errata published for each specification. From 1993-2005 no errata was published for the 1989 ASD Manual unless the change was considered a safety issue.
Some examples...
In 1993, introduction of Block Shear
In 1999, the loading requirements where referred to ASCE 7.
In 2005, Chapter K provides information for HSS walls.
etc....
JAE,
I agree that in some cases the current spec is less conservative. But, I believe that the current specification should apply regardless of economy. Luckily there are some good changes that result. If a building code, chooses to disagree with specific changes in a product specification, the exclusions should be specific and provide clear explanations.
Good or bad, our company's position is that the most current specification should apply exclusively. We are actively involved in the development of the Specification and Manual for Steel Construction. Involvement in this process, review of the research, and the committee discussions that result in improvements or changes, excludes our company from an "ignorance is bliss" defense. We have already began updating our programs to meet the changes in the 2010 Spec and 14th Edition Manual.
Perhaps the building codes should adopt wording that acknowledges that specifications change and provide a grace period for implementation of the changes.
Using the current code/spec is certainly a choice each of us should consider. Just keep in mind that the IBC, AISC spec, etc. are in-and-of-themselves just documents that have ZERO legal bearing on anything. They must be adopted into law to be in effect.
If I design to the current spec, and something goes wrong (be it my fault or otherwise) I need to be able to withstand an attorney's challenge: "Did your design meet all aspects of the adopted, legally standing code?".
If I use the newer code, I can say that my design was based on more current research, knowledge, etc., but I'd still have to say NO to the question. That can hurt in a jury's eyes.
I would suggest that if you decide to design to the lastest versions, you make damn sure you know where it is conservative and where it is unconservative (relative to the adopted code) and adjust your designs such that they at least meet both codes.
The new code is a good code. AISC FINALLY GOT IT RIGHT. Time to make the switch.
Designing with the 9th shouldn't cause any problems--I agree with Jae's comment's, (remember the supplement got rid of the stress increase):
1) Look at the new lateral buckling equations, the new code is far less conservative here.
2) The LRFD "factors" are calibrated so they match the old ASD.
My only gripe about the new code is that I wish they wouldn't list both allowable and phi-nominal values. It's cluttered and is like reading documents with two languages on the same page. I wish they'd just list only the nominal values in the tables and figures, and without the phi reduction, it would be so much easier to read, would work for both ASD and LRFD, and adaptable to specific instances where different safety factors are applicable, like in construction engineering. Otherwise, I really like the new unified spec's. Great job AISC. Now if AISC could just help the AASHTO bridge people get a clue!
I would suggest that if you decide to design to the lastest versions, you make damn sure you know where it is conservative and where it is unconservative (relative to the adopted code) and adjust your designs such that they at least meet both codes.
This is what I would say. You can't ignore the legal code simply because there is one that is more state of the art. If you insist on using the latest one, you still need to make sure the legal one is also satisfied.
I agree with JAE and Nutte that you should satisfy the current governing code, but you shouldn’t need three different editions of all other standards/specs. to comply. For years, we’ve used new research and thinking when it would benefit out designs. We did this by following the current technical literature and research activities. This fell under the phrases ‘by other rational engineering methods and, not intended to preclude other ration methods founded on sound engineering principles and judgement,’ which are included in most of the basic codes. Of course, we had to be able to justify and defend our designs, that hasn’t changed, that’s our job. How much better that?, than the situation we are in now, where the codes have gotten so complex that the formulas bear little resemblance to common knowledge of the way structures actually act and work, and practicing engineers spend most of their time struggling to understand if that formula or this one applies in this particular cook book recipe, without knowing if they are baking cookies or a pot roast.
I think we are debating the wrong point here. We, as the primary users of these codes, should say ‘enough is enough,’ take this edition and shove-it; you haven’t really improved the process, you’ve just made it more complex, made the code fatter and changed the color of the cover and some of the terminology, and cost me a bunch of time and money, without improving my life, or the public’s safety. And, I’ve talked to a number of building officials who feel this way too, they can’t keep up with the pace of the changes either. We’re tasked with interpreting the codes correctly and then using them to design and build safe structures; they’re only tasked with interpreting the code and arguing with us when the two interpretations don’t agree, and they can no longer keep up either. We should both be talking with the powers-that-be to slow the process down so that we can catch up. This will take a concerted effort because there is big money in publishing. But, let the publishers sit with the next edition or two, until they come up with real improvements to the codes, rather than just more complexity. Hell, we spend more time now manipulating load combinations and different load factors than it used to take to do a simple design, and there isn’t much indication that we are producing better structures, just much more complicated ones.
As I see it, the problem with all of the building codes these days that their production and the republication of new versions has become a very costly new cottage industry unto itself, which has diverged from its original purpose. The original/primary intent of the codes/specs. whatever the particular building material, should be to add some knowledge based uniformity and assistance in designing and building a safe, practical, reasonably economical structure which is safe to use for its intended purpose. The code’s primary purpose should not just be make-work and profit for the researchers and printers. The release of codes should be better synchronized and the time between releases extended sufficiently so there is some hope that practitioners might learn to use them and understand them before discarding them. Real safety issues, when discovered, should be handled by addendums and publications in the technical journals, etc. Errata should be issued periodically as they are found. But, otherwise let us use the same code book long enough to get to know it.
dhengr, you're preaching to the choir. If you look through this forum, you'll see the same arguments applied to Appendix D in ACI 318. And the response is always the same: "We have better information and research, why shouldn't the code reflect this better knowledge?" And it's tough to argue, "Use older(inferior) information, it always worked before." It's the eternal struggle between the practicing engineers and the research types. And until there's a failure, who's to say whose more right? But that's pretty drastic.
I've got caught in this chinese puzzle before and I don't want to again.
My thoughts exactly, Jed. I'm part of the choir. The thing is, I have never heard of a failure of a structural steel member, connection, or structure as a whole which had been designed and constructed in strict accordance with ANY recognized code. Failures are always due to poor detailing or misunderstanding, and unnecessarily complicated code provisions only increase opportunities for that to happen.
-It is easy to use. It is basically "six of one, half dozen of the other" as far as member design when compared to the Green book.
-It is black and looks cool
-I like the green and blue tables.
-the design examples on the CD cover almost every basic practical situation you might run into. Printed and bound it makes a great reference.
I don't like it because they took the stability chapter C from a few nice pages to many many pages when several different approaches and then threw in an appendix for the DAM.
I hope like hell they cleaned up this mess in the 14th.
Anyone know how they did Chapter C in the new one?
They should go back to gold-leaf like in some of the old Carnegie Steel Pocket Companions (I'm not sure if this was typical for any other similar publications, but I know the 1934 version I found in a used bookstore has it).
Here, here! Amen! In my industry, simple beats complicated any day. I get angry when others accuse some of us of being behind the times. Contrary to what some have said in this string, the latest code does not need to be used. The differences are minimal. For IBC2003 where applicable, 9th edition is acceptable. Can you immagine that? A 14 year code (at the time) was still acceptable?
And why is this??? There is a reason that we have this discussion every so often. Not everyone has a need to save "up to 5%" of steel cost that the latest code promises. Designing buildings to the lowest possible weight is not always necessary. A simpler code can co-exist with 13th. And let's make this perfectly clear. It was never an LRFD issue? We use this in concrete. It was always complexity.
This discussion would end if the code would add lines such as "in lieu of the last 2 paragraphs and 3 formulas , the following one formula may be used". I'll buy that code.
The point of newer codes is not to use less material, it is to recognize and restrain the use of new methods and technologies. Codes do not lead the industry, they are written by the industry to keep up with the engineers.
I preach against design using less material, slimmer sections, and stronger materials in the name of "savings", when doing so does not make engineering sense.
Engineering is not entirely about math, which seems to have gotten lost in the rush to exact solutions and precise computation or theoretical values.
To the issue of relative conservatism of new codes vs. older codes: I believe ACI 350-06 is significantly less conservative (at least for rectangular tank wall design) than the old 350-01. And 350-01 was easier to understand. For what that's worth...
Codes get thicker (but not necessarily safer), engineers get the same or smaller design budgets, lawyers flourish. What's with that?
"Engineering is not entirely about math, which seems to have gotten lost in the rush to exact solutions and precise computation or theoretical values." This is so true.
About 10 years ago when AASHTO LRFD was coming into general use I attened a seminar and one of the speakers stated under the new code bridge design will be very tedious, if not impossible, to do by hand because of all the new checks that were introduced. He added that since computers are common place it doesn't matter anymore.
I personally like the new dual code, though a bit clumsy at first it is nice to have both methods in one source. But my feeling with many new codes and specs is often why? What is the bottom line? I understand more economical design. And I understand if we were doing something wrong and research or a failure showed us the light, but why the constant tinkering?
I don't remember all the steel frame building problems we were having here in the US. Not sure what codes all of NYC were built according to, but they seemed to have had it right almost a century ago. Not like after every new code we are tearing down old steel buildings. Yep, I know, they were all overdesigned, but they are still around too.
I digress, and will just use the new code. So far I like it, its slimmed down, seems similar enough to both previous versions, and life is too short to argue about change sometimes.... Its inevitable, even when it seems unnecessacry
