ASD vs. LRFD, Who Decides? 5

[vmirat]

I just bought the fifth edition of Salmon/Johnson/Malhas "Steel Structures - Design and Behavior." This text book is focused on the LRFD method. In the preface, they state, "This modern philosophy of design [LRFD], discussed only briefly in one section of the second edition, is moving toward being the predominant approach to design."

There have been many posts to this forum about ASD vs. LRFD. Several people have commented in this forum that they were taught LRFD in school but that their engineering firm uses ASD. It seems apparent that academia has made the decision that LRFD is the best method and therefore the only method to be used. The question is whether academia should be driving this train or the industry? There is a form of social engineering (pardon the pun) going on here if academia is making the decision for us as opposed to the code committees.

Some have commented that, as far as the 13th edition of the steel manual goes, the results are pretty much the same regardless of which method you use. If so, then why the push for one method over the other in the academic world? Since both methods are related to code compliance, perhaps academia shouldn't teach either one and leave the code issues to on-the-job training or offer a separate course that covers all the code aspects.

My own personal desire is for one method for all materials: steel, concrete, wood, masonry, etc. I don't really care which one it is, as long as it's consistent. But, in my opinion, the decision as to what system is used should be made by the industry, not the teachers.

 

[nutte]

I would never suggest teaching ASD89. But 5 years ago, it was the best ASD around, so engineers were using it, like it or not.

When I say the two ASDs are the same, I mean the same concept, just different evolutions. The green book is a youngster, while the black book is the older, wiser adult. I whole-heartedly agree with your points about the organization and breadth of topics covered.

As for checking D+L for concrete, serviceability controls less often, so it is less of a hassle. After all, there are tables in ACI for beam depths so deflections need not be considered.

 

[271828]

kslee1000,

In a perfect world, I would agree with you. I've love to teach two undergrad steel classes, but there is simply no room for two.

Even if there was another one offered, as you suggest, people would take something else instead. After the basic steel class, they'd move on to take prestressed concrete, wood, masonry, matrix analysis, or some other course instead. Then they'd move toward taking a second class in a given material: Steel II, Concrete II, Nonlinear Matrix Analysis, etc.

I hate it, but there's just not enough room due mostly to the requirement of so many non-strl courses.

 

[kslee1000]

271828:

Make the 2nd one as summer class, since it really does not have much of materials to cover (sure you can beef up if you wish). As I have pointed out before, for my undergraduate program, we needed 2 (mandatory) class each from ME, EE, and one from IE, on top of 1 Env, 1 Geotech, 1 hydrolog/hydrulics. Yes, I had to spent a lot of time to perform self-study to catch up on work, maily in structural, but I am still given creadits to my all around studies.

I can understand your frustration from your standing, I had heard similar complains from two of my younger professors. I haven't been seeing them for a long while, but knowing both are doing fine. It must have take them a long while to adopt into the reality, and need - strategic/selective teaching. I don't mean to ignore something in teaching, but rather than teach your student line by line, maybe it is better off to teach them how to think and find answers themself. Above just my personal opinion based on my own experience.

 

[civeng80]

Like most other older engineers in the foram Ive always found it difficult to wrap my brain around LRFD. But Ive tried hard. I still do those ASD calcs aside to check things that I jus't cant do with LRFD.

But legally in Australia with AS 4100 which is referred to In Australia Building Code we have no choose but to use AS 4100 that is LRFD.

I got some consulting design from an old engineer mate of mine lately and to my surprise it was all in ASD. A certificate of Compliance was issued by his firm so it got through.

Can someone explain to me what sort of mess this is ?

 

[civeng80]

My point was that we in Australia have no choose but to use LRFD. But older engineers still use it and get away with it with The Certificate of Compliance even though it's illegal.

So I would be interested in hearing what others have to say about this point.

 

[BAretired]

Designing to the current code is a professional obligation of every structural engineer. Failure to comply could result in sanctions by his professional association if they become aware of it.

To falsely declare that he has designed a structure in accordance with the current code is unprofessional conduct and unskilled practice or possibly both. Engineers have lost their right to practice for such conduct.

If problems arise on a project for any reason and it is learned by the authorities that the structural engineer did not follow the current code, the consequences could be quite severe. It would be prudent to retain a good lawyer before going any further.


BA

 

[JAE]

Not sure about Australia but in the US the ASD and LRFD are both allowed by the codes so there's no issue there.

 

[civeng80]

As far as I'm aware (The Australian code) AS4100 is only a LRFD code.