Baseplate - Pipe Shear Lug Embedment

[efFeb]

Good Morning,
I have some very high shear forces on my baseplates and need something more than an extra embed or just the anchor rods to deal with this.
I'm thinking to add pipes as a shear lug. My thought is to slot these through the baseplate, and not weld them at all to the baseplate. The baseplate (which i may need to reinforce at these locations) just bears directly into the pipe lug.
I know how long the lug needs to be to work in bearing on the concrete, but I am blanking on how to figure out how much further it needs to go to reach fixity into the concrete:

If you have any thoughts i would absolutely apppreciate this
Thanks,

 

[KootK]

and need something more than an extra embed

I really feel as though a separate embed for shear ought to work and would be best. Or, if it doesn't, you have larger problems that this pipe thing can fix. Alternately, I could go for a true lug that is moment connected to the base plate. At least we have established procedures for that.

I know how long the lug needs to be to work in bearing on the concrete, but I am blanking on how to figure out how much further it needs to go to reach fixity into the concrete:

Be careful with "bearing". We used to rely heavily on that and, in these situations, it has often led us astray. As with studs, I would expect your true failure here to be some form of prying induced concrete breakout. So I would seek a methodology that:

1) Addresses prying.

2) Addresses the lateral stress pattern that you're likely to see on the HSS given the relative stiffness of the tube and the surrounding concrete.

All I can think of, really, is to treat the tube like you would a very large nelson stud. This won't be perfect, of course. But it's the best analog that I can think of.

 

[haynewp]

There is a breakout check. There has been an update to ACI and you don't get the capacity out of the normal shear lugs that you used to get, in case you are using the newer ACI versions.

 

[SWComposites]

is this a hollow pipe? if so, you need to ensure the baseplate does not crush the pipe .