I would suggest you cannot connect concrete to an earthing grid. Not sure why you would want to do that! appears a bit pointless.
However, if the columns are re-inforced concrete, you can connect the steel re-inforcing bars to form an earthing grid, but this requires specialist pre-design of the re-inforcing bars (re-bars) throughout the structure.
Normal construction fabrication of re-bar "nests" utilise lightweight "tie wires" , if you are planning to use the re-bars as the earthing for the building you have to assemble the re-bars with special clamps or welded together to form a good reliable joint.