Aluminum 1

[BSVBD]

I've been asked to design an ALUMINUM cross-over ladder "structure", with bar-grate platform.

In over 30 years, I've never "done" ALUMINUM!

Where do I obtain Design Values for Aluminum?

Is there a "PROPER" ASTM I should comply with? B308-6061-T6? 4047? 2026? The 6-page 6061-T6 "Standard Specification" I found online, does not provide the "Fb, Fv, I or E" I'm looking for.

Being all for innovation, yet, not wanting to be cheap, AT THIS TIME, I also do not care to unnecessarily invest in the effort for one-time-use of such design values, ESPECIALLY the wrong ASTM for Structural Aluminum.

Please advise... Thank you!

 

[jjl317]

I have always used the Aluminum Design Manual ADM for aluminum.

Short of that, not sure where else the information would be available.

 

[canwesteng]

I've only used the CSA aluminum design spec. Looks like there is an aluminum design manual that may be the US equivalent. Based on your post, you will certainly need to invest in the standard. Wouldn't worry too much about picking a strong temper, unless this is done in a shop that can re-temper the metal, the welds will only be as strong as untempered aluminum.

 

[phamENG]

Unless you're planning to do a lot of aluminum design, I'd suggest either sending the client to somebody else or finding somebody you can sub it to. Aluminum is deceptive. At first, it looks a lot like designing with weak, soft steel...but it's not. There are a lot of traps that you can fall into, and a lot of the analysis procedures are complex and less than intuitive.

You want the Aluminum Design Manual. ADM 2020. It's not cheap. But if you want to do Aluminum right, that's the place to start.

 

[dvd]

Attached is some good background info on aluminum weldments -

 

[rb1957]

would you 6061T6 be the same as ours (aerospace) ?

you can find material data online, either Mil HDBK 5 or MMPDS01 (up to 09).

personally I wouldn't weld Al, though I know you can. It matters if small production run or long.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[driftLimiter]

The aluminum code (ADM) has tables of values used for structural design of aluminum members.

 

[JStephen]

At tank-related trade shows, I've seen displays by these folks and one or two other companies offering similar products. If they can come up with something that fits the bill, that might be the way to go.

https://www.safe-harbor.com/

 

[Aesur]

As others have said, Aluminum is not like steel in design, I tend to still use the 2005 ADM because I'm most familiar with it, but this requires looking at the piece as a series of pieces for unique shapes and finding the design stress based on the various elements of the shape, think custom cold formed steel shapes, very similar. There are massive stress reductions for weld zones, re-tempering can be done to bring the capacity back up, however this is difficult due to shapes and sizes compared to the equipment used to temper, so is rarely done for commercial work. The alloys I tend to see are 6061-T6 and 6063-T6, typically 6063 has been used in items that need better finishes in my experience, like aluminum canopies. 6061 tends to be more used when most strength is needed. I have also seen some 3003 sheets used. Each alloy has it's uses, ie extruded, rolled, flat sheets, etc.. so you need to look at what is available in the market. For what you describe I suspect you will find 6061 as the most common.

 

[rb1957]

I thought 5082 was pretty common ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[BSVBD]

Thank you ALL for your replies!

BECAUSE of your replies, I am only providing miscellaneous detail drawings waiving EVERYTHING and specifying the following...

1) Structural aluminum angle, flat bar and plate shall comply with an ASTM specification as determined by Fabricator. Architect or Engineer Of Record are NOT responsible for Aluminum Material, ASTM Specification, Profile Sizes, Welding, Galvanic Corrosion from use of Fasteners of Dissimilar Metals, Fabricating Processes or Other.

2) All welds shall be the responsibility of Fabricator, in accordance with most current applicable version of AWS D1.2 Structural Welding Code for Aluminum Structures.

Am I missing anything? Suggestions?

Thank you ALL! VERY helpful!!

 

[dvd]

Are you going to provide loadings, or make that the responsibility of the fabricator also?

 

[phamENG]

If you're the EOR, it's still your responsibility to make sure they do it right...

 

[BSVBD]

dvd...
Yes! I provided the loadings.
No! I did not make that the responsibility of fabricator.
It seems inevitable that respoonsibility always comes back to either the architect and/or engineer!

phamENG... Yes! Agreed!

Thank you!