What spec governs built up box sections larger than 20x12x5/16

[HereTwoLearn]

AISC Rectangular HSS Sections go up to a max size of HSS 20x12x5/16. The design of sections up to that size clearly fall within the specification of AISC Steel Construction Manual.

What if you make a built up box section beam, for example, out of 1/2" plate to create a 24" x 18" x 1/2" plate box.

I am struggling to find a clear definition of sizes where AISC spec no longer applies, and what specification would apply in this case.

Any advice is appreciated.

 

[nutte]

Material specification ASTM A500 covers shapes up to HSS 20x12. The AISC design specification in the Steel Construction Manual can be used to design those shapes as well as the built-up shape you're describing. There is no maximum size that I know of for using the AISC specification to design your box member.

 

[paddingtongreen]

We once got into a lather when QA demanded that our large (28' square in that case) flue gas ducts be designed per AISC. They backed off when they saw the result compared with existing, long lived ducts.

If it is a structural member and not a bridge or other separately coded structure then AISC rules. Our duct was not carrying anything else so it was not an AISC item.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[ToadJones]

Pad
Been there!
Duct work for a coal plant?