Yes, you need to tie the new concrete into the old with pins. Drill holes into the sides of the new pits and insert either cut rebar or bolts (3/8 inches or more in diameter) into them, so they are embedded into the old concrete and the new concrete at least 3 inches in each. Use at least two on each side. Keep the pins 4 or more inches from the corners and away from where your anchors will be. Consider using L threaded anchor bolts instead of the wedge anchors. Make a template to hold them In place while You pour the new concrete.
no, you don’t need to add rebar or welded wire mesh in the new pours.
