Threaded Stud to HSS Connection 4

[Boiler106]

I'd like to weld a 1/2" dia A108 threaded stud to an HSS face and attach a plate with a standard hole to it, such that the plate sits flush to the hss face.

I am seeing that the base weld for a 1/2" dia threaded stud is 5/8" in diameter, which would interfere with the plate with a standard hole.

it would seem I would need to provide an oversized hole and a slip critical connection to apply any kind of shear force to the stud.

I'm dealing with relatively small loads, so is there another solution out there i am not seeing?

 

[JAE]

You can use a small "donut" washer plate with a larger hole under the main plate but that would create a small stand-off from the tube. You indicated you want the plate to be flush with the tube so that might not be an answer.

The other way is to have an oversized hole in your main plate, have that plate flush with the tube, then use a 3/16" larger washer plate with a standard hole over the main plate. Then weld the washer plate to the main plate.

The only other thing that comes to mind here is using a chiseled point on your stud and create a sort of double groove weld at its end to avoid the extended fillet condition.

 

[msquared48]

Or, you could drill through to the opposite side of the tube, use an A36 threaded rod, and make the weld on the other side of the tube.

Mike McCann
MMC Engineering

 

[dhengr]

Boiler106:
You might put some fairly tight controls on the oversize of the stud fillet weld, or grind it a bit to clean it up. Then have the fabricator or a machine shop make some small countersinks on the back side of the plate to clear the weld. Some/much screwin around. Then you have to check the studs as short cantilevers w.r.t. shear loading. This shouldn’t hurt friction btwn. the pl. and the HSS much (slip crictical??), use a heavy washer under the nuts. Like any other bolted connection on an HSS you could still have out of plane pl. bending on the tube face.

 

[SAIL3]

You may want to try Hollo-Bolts instead of welding a stud to HSS face...

 

[EngineeringEric]

if not Hollo-Bolts like SAIL commented there are PJP welds which would be smaller but this is not a highly loaded connection i assume...

 

[Boiler106]

Guys, very good input. It is a pretty lightly loaded connection and most forces comes from wind uplift, putting the stud in tension, although I needed to guarantee a nominal amount of shear capacity.

I decided to go with the countersunk heads, and not do a thru-bolt due to architectural considerations.

I eliminated the blind bolt due to regional contractor reluctance and the penetration in the exposed hss member.

I should note that AISC also recommendeds the countersunk holes on pg 7-15 14th ed for threaded studs.

Also, I'm not convinced that bending of the stud needs to be considered in a plate mounted flush to the hss face, but I welcome any further comment.

Finally, for future reference, the dimension E in the attached pdf from Nelson Stud indicates the weld diameter, although it is never shown in their diagram.