Concrete Void At Beam Column Junction

use two steel HP Column to substitute the difference/lacking of column bearing capacity
i.e steel column will replace the empty void .
done this before for multistory

ALK2415 - That seems like it could produce a hinge at that location? I would tend to think that a concrete replacement solution would better maintain flexural capacity of the column and the beam...

I wouldn't recommend patching with mortar. Mortar and concrete don't bond properly and that will be a waste of time and money.

"and redoing the concrete a better solution?", sounds better to me

You can have a look at this rough annotation. I think that looks more reasonable to me.

Looks like pretty crappy concrete work. Photos are not clear enough to say for sure, but I would be concerned about the ability of the contractor to perform a satisfactory repair.

The bars in the column look small, but that could just be perspective.

You say "don't worry" about the shoring. I hope it's a lot better than the "shoring" we see in the photo.

I'm not endorsing anything, but if they are going to hack off existing concrete and install new, require them to go after the old concrete with a steel brush to clear as much laitance as possible and follow as closely as they can the shear friction provisions for surface preparation (I don't see a 1/4" amplitude roughening of the column with all that rebar in there. You also want the surface wetted, before the new concrete is placed, as already mentioned here.

I would also suggest you re-check the bar placement for appropriate clearance between the bars based on the maximum aggregate size in the mix and get some cores. This column may not look crowded/congested but make sure it is not beyond 4% of the vertical cross-sectional area.

That said, the pour sequence looks odd. Did they pour the concrete into the column at the same time as the slab? Hence the void in the column and the void in the slab area as well? That doesn't sound like normal practice, particularly if the concrete column is higher strength concrete than the floor, unless they are pouring that high-strength puddle around the column at the floor level?

Regards,
Brian