HSS WALL PLASTIFICATION! 4

[Ben29]

I am doing a connection design for a fabricator. The beam has an axial load of 110K on each side of a column. Fabricator wants to use a shear plate connection. The shear plate connection is failing... the limit state is HSS Wall Plastification. My question is: Can I add a plate below the beam (weld to column and beam flange) in order to help transfer the axial load along a wider area? See image below. Thanks in advance.

 

[Ben29]

So if I am understanding this correctly, the EOR noted the "axial force" on plan to be P = +/-110K and this force is shown on either side of the column. Is the term "axial force" not correct? It is really just the transfer force? And the total transfer force is taken to be 110K? If so, then I could get a thru-plate to work for 110K. I couldn't get it to work for 220K, as I stated previously.

Don't worry - I am definitely getting out of connection design after this.

 

[Ben29]

@Enable,
Thank you for that explanation. I entered my last message before I saw yours.

 

[wrxsti]

ben ill agree with Enable only the EOR Can provide the correct answer unless you are willing to redo entire structural analysis

all the speculation means nothing unless confirmed by the EOR or proper analysis

i also agree due to the 165kip in the brace ( to be confirmed with EOR?? )

which resolves closely to 110kip

that there should be no transfer force (force continuing to the opposite side of the column)


proper understanding is needed of what value is to be entered as transfer force in your software

which may be part of the program to control how much load from the beam axial will transfer into the bracing




there was an article

https://www.eng-tips.com/viewthread.cfm?qid=206933

that speaks about this but the links are dead

hopefully someone will provide some insight

 

[gtr35]

is it possible that 110kip is the transfer force up and over the amount of
the axial in the beam that the bracing was designed to take transferring down the line
to another brace?

 

[EngStuff]

Out of curiosity, assuming the load is meant to transfer over to the other beam. If the force was low enough that the HSS member can handle it. Would it be necessary to call out a through plate? Or would a typical shear tab on both sides should be be good enough! I remember at a webinar It was mentioned that it was about 4x more expensive to design a through plate.

 

[DrZoidberWoop]

If I was to design this connection using the dimensions you've provided, I would use roughly:

Beam to Column Shear = Beam Rxn + UFM = 65 + 54 = 119 kips
Beam to Column Axial = Req'd Axial/Axial Transfer + UFM = 110 + 23 = 133 kips
Gusset to Column Shear = 0 + UFM = 0 + 62.9 = 62.9 kips
Gusset to Column Axial = 0 + UFM = 0 + 23 = 23 kips

This comes from the modified uniform force method presented in Ch. 13 of the AISC SCM and this paper by Larry Muir:

https://www.aisc.org/Designing-Compact-Gussets-with-the-Uniform-Force-Method

I would consider the 110 kips an axial transfer through the HSS, but I'd provide a bubbled note requesting verification by the EOR.

A through plate would be used at the beam here, even if the HSS wall could handle it. Most of the time, the fabrication cost of cutting the HSS and applying the AISC Table J2.4 minimum weld is cheaper than using multi-pass welds.

 

[wrxsti]

here i hope this helped... taken from dg29

determining transfer forces

TF = 1x+2x+6x or TF = 3x + 7x

design example

what does your drawing mean does it mean one of these?

 

[EngStuff]

A through plate would be used at the beam here, even if the HSS wall could handle it. Most of the time, the fabrication cost of cutting the HSS and applying the AISC Table J2.4 minimum weld is cheaper than using multi-pass welds.

At what percent capacity would we not require it? If the HSS wall plastification say had a capacity of 90kips and we had a required load of 20k or a 10k or 5k tension load. Would it be necessary to use a through plate? What is the rule of thumb?

Thanks!