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HSS column at base plate with no workable flat 2
- Thread starter Eng456123
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TRAK.Structural
Structural
Figuring out the exact capacity from flexural loading seems like a complicated geometry problem.
As a lower bound you could use Blodgett's welds as lines method with a geometry of a square that fits within the actual shape of a weld around the tube.
As a lower bound you could use Blodgett's welds as lines method with a geometry of a square that fits within the actual shape of a weld around the tube.
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- #3
@TRAK Thanks. Agreed. That seems like a reasonable solution, thanks!
A coworker suggested sizing the weld to develop the capacity of the HSS? But I was struggling to see where he was going with it or how you would actually calculate it. We started in Table J2.5 where it says the base metal is governed by J4. But J4 gives you a capacity, which you would need to compare to another capacity (of the weld) which is back to square one...?
A coworker suggested sizing the weld to develop the capacity of the HSS? But I was struggling to see where he was going with it or how you would actually calculate it. We started in Table J2.5 where it says the base metal is governed by J4. But J4 gives you a capacity, which you would need to compare to another capacity (of the weld) which is back to square one...?
DrZoidberWoop
Structural
With small square & rectangle HSS members, you'll have to use engineering judgement or market knowledge to estimate a reasonable effective weld length/workable-flat (or google the shape and give a conservative guess).
There are a few quick and dirty approaches to welding HSS like this.
1) CJP and avert your gaze from mean looks from fabricator.
2) Size the fillet weld for the required flexure via a conservative flange force method (ignoring 2 walls of the HSS weld group)
Ff=Moment/hss_d and D_req = Ff/(weld_factor*estimated_effective_weld_length)
<
D_max_sixteenths = phi_r*0.6*Fu_hss*design_wall_thickness_hss/weld_factor (variant of AISC Eq 9-2)
where: phi_r = 0.75 (LRFD) or 0.5 (ASD) and weld_factor = 1.392 (LRFD) or 0.928 (ASD)
3) You could also do an elastic method calc with the full weld group (Alex Tomanovich spreadsheet kicking around the internet).
4) Apply D_max_sixteenths and ask for EOR verification. If not acceptable, propose to use thicker hss for required loads.
There are a few quick and dirty approaches to welding HSS like this.
1) CJP and avert your gaze from mean looks from fabricator.
2) Size the fillet weld for the required flexure via a conservative flange force method (ignoring 2 walls of the HSS weld group)
Ff=Moment/hss_d and D_req = Ff/(weld_factor*estimated_effective_weld_length)
<
D_max_sixteenths = phi_r*0.6*Fu_hss*design_wall_thickness_hss/weld_factor (variant of AISC Eq 9-2)
where: phi_r = 0.75 (LRFD) or 0.5 (ASD) and weld_factor = 1.392 (LRFD) or 0.928 (ASD)
3) You could also do an elastic method calc with the full weld group (Alex Tomanovich spreadsheet kicking around the internet).
4) Apply D_max_sixteenths and ask for EOR verification. If not acceptable, propose to use thicker hss for required loads.
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2
- #5
centondollar
Structural
Sizing a weld for the force resultant, assuming it to be under pure shear, is conservative (see any textbook on steel design for the derivation), so just equate the HSS yield force (area*yield stress) to the strength of the weld in shear (weld strength * perimeter * throat thickness) and solve for throat thickness - this provides (in theory) a full strength connection.
SteelTubes
Structural
You might find the Steel Tube Institute's Effective Weld Length Calculator helpful.
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