HSS Hollow Steel section design vs. Roarks flat plate 3

[jreep1973]

Is it appropriate to use Roarks flat plate formulas in determining the wall strength for HSS hollow members?
I have a HSS tube column that is seeing a 10k lateral load from a direct weld of a 3"XXS pipe. In the past I have used Chapter K of AISC 360 for Design of HSS and Box member connections. However, I am reviewing an engineers calc's in which they used Roarks formulas, and I don't think it adequately applies. Or better yet, I wouldn't think it would be more appropriate than Chpt K of AISC 360.
Thoughts, PLEASE.

 

[driftLimiter]

Roarks is based on elastic behavior and idealized end conditions of the plates. AISC is based on yield line theory and testing on actual HSS profiles.

If doing the review I would compare, if Roarks is saying something passes that AISC K doesn't like then my conclusion is Roarks not appropriate.

 

[jreep1973]

Thank you driftLimiter

 

[Lomarandil]

Note that AISC now includes some yield line solutions for flats of rectangular HSS in the "manual" portion (not the specification)

 

[dik]

I would use Packer et al's excellent articles, including the AISC code for these connections. I wouldn't be looking at Roarks' stuff.

I just renewed my STI membership today... excellent organisation and lots of literature...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[lexpatrie]

Yeah I don't see how Roark's would apply now that the specification directly addresses it. Try the folks at the Steel Tube Institute. It's perhaps legacy calculations and they haven't updated it.

 

[HTURKAK]

In this case , the joints are tubular joints. I will suggest you to look
API RP 2A- WSD Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms,
There is also Recommended Practice with LRFD .




Use it up, wear it out;
Make it do, or do without.

NEW ENGLAND MAXIM

 

[271828]

Is it appropriate to use Roarks flat plate formulas in determining the wall strength for HSS hollow members?

Does Chapter K have a directly applicable equation? This probably depends on the edition.

In the 2016 and 2022 Specifications, there's no entry in the table for a rectangular HSS with one pipe branch member applying a transverse force. Section K3.3 says to use Chapter J. Section J5 is very general, so the limit state can be checked using Roark's formulas, FEA, yield line analysis, or any other rational method. Thus, assuming I understand the situation correctly, they could use Roark's formulas -- to check out-of-plane bending, aka plastification. Roark's is linearly elastic, so I would expect the strength to be a lot lower than if they used YLA from Part 9 of the Manual.

Here's the big question for me: What are they claiming is being checked by Roark's formula? There are lots of other limit states, such as punching shear, weld strength with uneven force distribution, etc. I'd be looking at STI to see if Packer or anybody else has an article for this exact scenario. They often do.

 

[SteelTubes]

There is in fact an article by Dr. Packer that addresses round to rectangular connections, which the Steel Tube Institute publishes:

https://steeltubeinstitute.org/resources/round-branch-rectangular-chord-hss-connections/

Additionally, the Steel Tube Institute publishes Limit State Tables which outline Limit States to be checked for various scenarios. It includes round HSS to HSS, and rectangular HSS to HSS T connections. It does not specifically include round to rectangular connections.

https://steeltubeinstitute.org/product/aisc-360-16-limit-state-tables/