I got the 3/4" diameter from Tablee 14-2. I was treating the base of the equipment like it is a base plate to rationalize this. Nothing I know of addresses slotted holes in base plates so it's going to more of an engineering judgement than a hard and fast rule.
The structure is determinate and stable but is not recommended because it is susceptible to cascading failure. If either of the columns on the right side were to fail the entire structure would become unstable. The preferred method of constructing a continuous beam line like this would be to...
In addition to determining whether the slab is post-tensioned or reinforced with mild reinforcing what is the location of the proposed core drill in relation to the columns below? If you are core drilling within the critical shear perimeter of a column you are reducing the punching shear...
The minimum size of the bolts is dependent on the direction of the load being passed from the equipment into the structure.
If the mounting bolts are purely for axial loads then I would propose detailing the mounting bolts using criteria similar to anchor rods at base plates. A 3/4" diameter...
In addition to what jayrod12 wrote above, per ACI 318-08 7.10.5.4, provide ties not more than half a tie spacing above top of footing or slab and not more than half a tie spacing below lowest horizontal reinforcing in slab, drop panel or shear cap above.
For columns with beams framing from 4...
