AISI 1986 Design Manual CFS 1

[profplan]

I am trying to make a decision to purchase either the 1986 or the 1996 edition of the AISI Design Manual (available online at AISI store) for the design of cold formed steel (light gage framing) and need some advice from those who have used both. Any preferences and why?

I generally only review light gage framing design by a specialty engineer to confirm structural performance requirements are met, in practice. However, I've had a a few requests from contractors to perform specialty light gage design services. I like the older codes as a design reference and check, even if I am going to be designing to the current code, in this case, the AISI 2007 specification.

Thanks.

 

[dhengr]

Like all of us, as we deal with these damn codes, manuals and all the design software, proliferating these days, you need $400,000 worth of this constantly changing junk to do $1000 worth of engineering if you want to meet the letter of all of the governing building codes, at any given moment and many different locations.

What you probably need most is a couple of good reference texts on the subject, so that you get the theory and concepts down pat. The Univ. of Missouri - Rolla does a lot of work in this area, and Prof. Wei-Wen Yu has (had) a good text on the subject, and George Winter, from Cornell, before him. Then get yourself a good design and analysis software package on the subject; one that you really learn to use and trust, and really understand it minor nuances. After that it just becomes a constant, never ending, effort to keep up with all the changes in reduction factors, adjustment factors, resistance factors, load factors, etc. Most of these have little to do with the real theory, or good, careful, reasonably conservative design; but everything to do with selling new publications, and the latest research of Ph.D. candidates and universities.

It’s a sad state of affairs, but structural engineering has become much like cooking, just follow the damn latest cookbook to the letter, never mind what your are cooking. Now, when it says a pinch of salt, we can argue for hours about how much a pinch of salt really is, irrespective of the fact that we have lost sight of what we are really cooking, for all the intervening minutia.

 

[spats]

Dang dhengr! Pretty cynical! Having a bad day?

 

[hokie66]

Sounds to me like he's having a particularly good day.

 

[MiketheEngineer]

Best to go with the latest codes.. or else some lawyer will ask why you didn't!!

 

[profplan]

Thanks all. I plan to design according to the latest AISI Specification 2007.


dhengr - I understand your frustration with the ever changing codes. I'll take your advice and purchase the latest edition of Wei Wen Yu's Cold formed Steel textbook. I don't know how much information on items such as bracing, connections and construction details is included which sometimes get less emphasis in textbooks.

 

[dhengr]

Profplan:

I’d study the calcs. and shop drawings that you are now reviewing, and start saving copies of those for your job files and for your own reference, for typical and industry std. details and such.

My copy of Yu’s text “Cold-Formed Steel Structures”, Design, Analysis, Construction” is the 1973 Ed. and it does have material on bracing and a whole chapter on connections. And is particularly good on basic theory and getting you thinking about light gage materials and sections and how they behave differently than heavier hot rolled sections. Of course bracing, light plate buckling, width/thickness ratios, edge stiffeners, and the like become all the more important on these light sections. The AISI Spec. will have plenty to say on all of these, over and above the basics you get from Yu’s book.

Regarding the Design Manual, I don’t have the 86 Ed. and do have the 96 Ed., but haven’t used it enough to comment on one or the other. Suffice-it-to-say, it has a wealth of info. and you’ll have to use it awhile to become familiar with it. Read the Commentary section first, right along with the text, they’re both by Yu. The latest Ed. is probably the one worth purchasing if you are serious about getting involved in cold-formed steel design. If you are fairly new at this, but serious about it, why would you start with an older Ed., we aren’t moving backwards in terms of codes and manuals. And, the latest manual will most closely conform with the latest codes and specs.

I also have an AISI “Residential Steel Framing Manual” which has a wealth of detailing, design and construction info. in it, and is probably worth having on your shelf. Much of this material will be applicable to residential and/or commercial, as long as you pay attention to the differences btwn. the IRC and the IBC.

 

[profplan]

dhengr,

Thanks again. I have collected a few past designs (light gage/cold formed steel) over the years, the recent ones have mostly been software analysis which are less helpful.

A search indicates the latest Yu's text book, 4th Edition (2010), includes all the provisions for the latest AISI 2007 Cold formed steel specification according to the preface, and lists at $116, used for $80 at Amazon. The 2nd Edition (1973) is also still available used for under $10.

I am biased towards the older manuals... my first steel manual was the AISC red book. I find the manuals of that vintage are easier to apply directly to project designs. My plan would be to use the AISI 2007 specification but check upper/lower bound using the older manual.

I can't seem to find the AISI "Residential Steel Framing Manual" you refer to, but there is a new publication called AISI S230-07 "Prescriptive Method - 1 and 2 story family dwellings, 2007".

I am a sole practitioner/consultant, and am hard pressed to buy multiple codes and references. Your advice has been very helpful.