Shear tab welded to supporting member AND supported member
Shear tab welded to supporting member AND supported member
(OP)
Does anyone see an issue with welding a shear tab to both the supporting AND supported member? AISC only provides a procedure for bolting to the supported member. Is there a reason for that?






RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
The fact that AISC is silent on this topic should also raise some red flags. I'd recommend avoiding this one like the plague.
RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
DaveAtkins
RE: Shear tab welded to supporting member AND supported member
Redundancy is always a plus to final strength. There is also the code question, sometimes merely trying to keep the things in a particular practice, but sure there must be others that also work.
RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
Surely the fact that the beam flanges aren't connected to the shear tab can be used to justify some pinned behavior, right? I'm going to concentrate my welds around the center of the tab to try to minimize the moment transfered.
RE: Shear tab welded to supporting member AND supported member
I would be careful with welding like that. You don't want to initiate a crack and have it unzip. Can you provide slip-critical bolts in the LSL?
RE: Shear tab welded to supporting member AND supported member
Also, do welds really unzip? Don't they have some minor ductility themselves?
RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
I know they allow welded-welded single angle connections because the angles can flex, but I am not sure if a welded-welded shear tab is recommended. I am not saying it won't work, but would you want to use it everywhere every time?
RE: Shear tab welded to supporting member AND supported member
You still have to look at moment strength, but as you know the LSL doesn't allow for that because the bolts can move in one direction (This isn't quite true if you have more than one vertical column of bolts, but let's leave that aside for now). If you make it slip-critical and use the slip at strength level loading, then you should be good for counting on no slip right up to ultimate loading.
RE: Shear tab welded to supporting member AND supported member
Anyway, the point was that I used the procedure outlined in my concrete text (McGregor/Wight), because I couldn't find any easy to follow references for steel. The concrete example was easy to follow and implement.
RE: Shear tab welded to supporting member AND supported member
No, I would use welded-bolted shear plates. Some use bolted-bolted. But if I had one where the bolts didn't line up for some reason, an acceptable fix would be to weld the plate to the supported member, provided of course the misalignment is not very much. You would then just have a similar situation as if you cut out both flanges of an otherwise intact section. Still a pin.
RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
I wouldn't want to do it because you are probably going to have field erection bolts anyway to get it plumbed up.
RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
Shear tab is not actually in my vocabulary, but I thought I knew what it meant. I was talking about a shear plate connection between two beams, like in a cantilever and drop-in system. If the term only applies to a beam connecting to a column, no, bolted-bolted doesn't make sense.
RE: Shear tab welded to supporting member AND supported member
A shear tab is a plate welded to the column and usually bolted to the beam web. Field bolting is more practical than field welding, so that would be the norm. In the event that bolt holes do not line up, would you not still consider field welding to be acceptable?
BA
RE: Shear tab welded to supporting member AND supported member
RE: Shear tab welded to supporting member AND supported member
It is just the terminology that is different. In Australia, we just call it a shear plate or web plate. The word "tab" sounds a bit flimsy, but as long as everybody knows what it means...
As I stated above, I have no problem with a welded-welded shear "tab" to solve a fitup problem.
RE: Shear tab welded to supporting member AND supported member
Thanks, I tend to agree. I would prefer the welded/bolted connection but would settle for welded/welded if required by other factors. There should be enough elasticity in the welded connections to accommodate normal beam rotations.
BA