13th Ed. AISC Manual / Spec.

[271828]

I'm curious what are your opinions of the new Manual and Spec.

A few general opinions:

1. I hated Ch. F at first, but love it now. Sure it's big, but I think it beats the snot out of the older specs that scattered those provisions through about 4 chapters and appendices. I've had to work with the 89 Spec. a little lately and it seems devoid of logic after working with the newer Spec. for a while now.

2. I think the ASD green shading is too bright in the design tables. When using LRFD, I find my eye drawn to that green. Maybe it's just me, LOL.

3. It weighs almost exactly 4.00 lb. Bad compared to the 89 Manual, but good compared to the 94 Manual!

4. I think Chapter 5 is a waste of a few dozen pages. Does anybody here actually use that stuff? How hard is it to use Eq. H1-1 anyway?!

 

[271828]

Oops, I meant Chapter 6 in Item 4.

5. The User Notes kick butt!

 

[JAE]

Haven't used it too much yet...not too many jurisdictions have adopted the IBC 2006 yet.

 

[271828]

JAE, that surprises me a little. Some of my buddies have already had to start using it. Perhaps it depends on location.

FWIW, in the past, we just started using new provisions even before they were adopted. ASSUMING of course, that there were no incompatibilities.

BTW, is it normal for threads to vaporize around here? I've seen two that didn't have fights or other nasty stuff, but just disappeared.

 

[JAE]

271828,

We had a long discussion here at Eng-Tips some time ago about the concept of using the "up-to-date" codes/specs such as ACI 318 and the AISC Steel spec vs. using the actual referenced code/spec version in the applicable building code.

As you know, the IBC uses Chapter 35 to lock in direct references to outside codes and standards. This has the effect of legally restricting what the full impact/content of the building code is...especially so now that the newer IBC's use a heck of a lot more outside references.

Personnally, I think it is a mistake to use a more current code or spec than what has been adopted by the jurisdiction as many times the two just don't mix.

Having said that, I think there is validity in at least KNOWING what is in the new spec and understanding the new changes and what they are based upon.

For example, right after the Northridge quake some years ago, there was an immediate discovery that much of the traditional moment connections in steel were inadequate and AISC proclaimed immediate holds on certain provisions within their seismic standars. Many jurisdictions set up their adopted codes to allow for supplemental provisions, errata, updates, etc.

However, some cities don't and as an engineer looking out for public safety there is no reason you can't use a more current code assuming that it is more conservative than the adopted code.

But totally going to the 13th edition and using it on each and every project despite the legally adopted code is going a bit too far in my opinion.

 

[271828]

I guess we didn't really do anything very radical, mainly things like using the 3rd Ed. LRFD Manual before it was adopted. It really wasn't much different from the 2nd Ed. Manual. Same goes for ACI for the most part. Loads are a little tougher of course.

Definitely have to watch for things that don't match and be careful. As long there's nothing unsafe, no bldg official freaks, and nothing mis-matches, I don't personally see a big problem with sneaking ahead a little.

FWIW, I used yet-to-be-adopted provisions a couple of times on projects with calc submittals and nobody every said anything about it. Granted, that won't happen every time.

 

[JAE]

Perhaps your submittals were reviewed by bldg officials that really wouldn't know the difference?

 

[271828]

LOL. Entirely possible!

My reasoning is that it's better to use updated information as long as nobody smacks me or if it causes me to make a mistake (load combo factor incompatible with phi factor perhaps?).

For example, I was just working on an ASD 89 application that req'd sidesway web buckling to be checked. The 2005 ASD sidesway web buckling provisions are updated and more accurate. From an engineering standpoint (non-pharisee), it seems closer to wrong to knowingly use equations that don't reflect our "best" knowledge.

Anyway, that's how I see it. I need to go find that other thread to see what others here think of the topic.

 

[civilperson]

Threads that are duplicate postings vanish!

 

[JAE]

Here are a few past threads with a similar topic:

thread172-154198

thread167-85713

thread507-177716

thread507-182571

 

[271828]

Cool JAE. Thank you very much.

CivilPerson. That's funny. I was starting to question my sanity!

 

[271828]

In one of the other threads, somebody mentioned Chapter C and how it is confusing. I agree completely.

Hopefully the ELM will be getting the boot in the next Spec. or two. That's some confusing stuff when done right. Check out the new Stability Design Guide. That's some nasty stuff.

The Direct Analysis Method will be Chapter C next time and the ELM will be in the appendix. Hopefully that's how it'll be ushered out the door!

 

[DonPhillips]

It is not that the plans examiner and building official do not look closely at the submittals, but Chapter 1 allows you, the designer, to use an alternative compliance method that the building official can accept. The latest codes would meet that standard unless there is a less stringent provision in the newer code, in which case, you have to adjudicate it through the appeals process. This is usually supported by the building official and approved by the appeals board.

Don Phillips

http://worthingtonengineering.com