AISC vs foreign steel sections-Any objection you know 5

[IJR]

Pals

I have been using AISC code to design welded I-sections and even European sections.

In both cases my only concern was to satisfy AISC provisions with respect to strength of sections as governed by b/t ratios(and stress conditions of course) as well as using grades that are very close to those prequalified in AISC, mostly close to ASTM A36

All authorities so far have not questioned my practice

Now some authorities are insisting that when I use AISC I should also limit sections to US sections.

I fail to see the sense in this demand, but I have to come up with a good explanation.

Any other explanation besides strength vs b/t and grade equivalence?

respects
ijr

 

[rday]

Design theory does not care where the steel came from on the planet. The same laws of physics that the code was built on still apply.

 

[IJR]

Rday

Thanks for your opinion, but what I am looking for is a better explanation than the one you are suggesting.

respect
ijr

 

[HgTX]

What's wrong with his explanation? Stress, strain, etc. are independent of country of manufacture. As long as you have the right section and material properties, what on earth could possibly matter?

The AISC steel manual is a collection of items. One item is the design code. One item is the code of standard practice. One item is the bolt spec. One item is a list of common sections and their properties, redundant with ASTM A 6, provided for designer convenience. Other items are handy-dandy design aids like graphs and tables, also provided for designer convenience. Only the code parts are mandatory (if specified).

If a job was designed with U.S. sections in mind, and then someone substitutes another section, why should that change anything about the calculations as long as you update the section and material properties?

The only possibly revelant material properties not part of the "plug and chug" of the code formulae would be elongation and toughness. As long as you verify that those properties are compatible with typical U.S. steels, and thus similar to what the framers of the code may have had in mind in terms of stress redistribution, etc., there's no problem whatsoever. Material is material, and the code is not specific to any given mill.

Hg

Eng-Tips policies: faq731-376

 

[rday]

I don't believe you'll find what you a looking for in the code. For purposes of the AISC specifications, only steel which carries an ASTM designation is approved. If evidence of conformity with an ASTM spec can be provided, the specifications could be applied.

That said, the code is still predicated on base principles and those will apply regardless of the steels' country of origin. Drawing design guidance from the code seems appropriate.

 

[DRC1]

Because of "Buy American" clauses in Federal contracts, AISC desginates which shapes are listed in the manual that are not available locally. Therefore AISC does recognize sections that are not rolled in the US. However, since they are probably rolled to metric dimensions, you should probably use the metric tables. They were availble in a prevous version, and are probably avilable from AISC.
AISC is very helpful with such questions and if you were to call could probably give you all the details to your question. If you do call, please post what they tell you as an answer.

 

[dik]

The AISC HSS specs are a little less than those for Canada and the HSS using ASTM A500 steel is downgraded a bit to reflect the differences in section properties. The same could be said of another standard in another part of the world.

Dik

 

[JoshPlumSE]

I've worked on a few international projects where there were questions about where we were getting our steel from and what shapes they would be. Slightly different from your situation, I know. But, the solution that we have might help in your calse.

Since it was a large project, we came up with a list of "equivalent" AISC shapes and materials for the project. The equivalent shapes was just a comparison of the AISC A and I values that listed the nearest foreign shapes to the AISC shapes that we called out in our design. Since we didn't know who our steel suppliers were going to be, we used to allow various vendors to bid off of the same pre-liminary drawing.

I wasn't involved with the material portion of the specs. But, I suspect that we also did a comparison between the foreign material specs and made sure that they followed the ASTM requirements closely enough to be considered equivalent. If you do a line by line comparison of the material data (Fy, Fu, maximum yield to tensile ratio). I'm not sure that I'd go so far as comparing the carbon and manganese composition, but you probably could.

 

[IJR]

Since I am not in US, I dont think I will write to AISC. But here is how I solved the problem:

I wrote a technical report discussing 4 issues: 1)That both AISC and European codes recognize GENERAL PURPOSE STEELS, which in US are grouped in ASTM A36 whereas in Europe they are grouped in EN 10025-2
2)That the two compare closely well.
3)That criteria in selection of steel grade in both codes are the same, namely yield strength, elongation(stress-strain), notch toughness, weldability and corrosion resistance, and that the grades match very well in this respect, and criteria for sections are the same, namely b/t ratio limits for given stress conditions and yield strengths
4)That both codes do not prohibit use of grades or sections that are not prequalified in respective codes, and they allow engineer of records to work on that using code provisions.

respects
IJR