Transferring steel column base shear through bearing in a ground floor slab?

[abusementpark]

For relatively low shear loads, I've often argued that the shear load gets transferred through bearing between the column and/or base plate and the ground floor slab. However, I've been hesitant to rely on this mechanism for larger loadings (say > 50 kips) because I am unsure about all the necessary design checks.

AISC Design Guide #1 has a design example of this shear transfer mechanism and all they do is an allowable bearing stress check. Seems to me like you also might need to check in bending in the steel elements that are transferring the load.

What about further design checks on the concrete? Seems like there could be a breakout or bucking mechanism? Also, what if column blockout were used? Could the blockout pour fail somehow?

 

[TLycan]

You have three possible ways to transfer shear according to Design Guide#1

using friction between steel plate and grout
using bearing and shear lug against concrete surface
using anchorage

The design guide#1, second edition, checks on the bending of the shear lug and the breakout of the concrete. Page 42 and 43

 

[abusementpark]

using bearing and shear lug against concrete surface

I believe AISC Design Guide 1 treats these as two separate types of transfer mechanisms. For their shear lug design example concrete breakout is checked. For their column bearing example, concrete breakout is not checked.