Old trick here or at least to me,if I plan on leaving it in place I use
regular galv. nails and copper grounding wire.

Drill a 5/32 hold in the concrete and wood then insert a piece of copper
wire with a little "L" hook on end so that as you drive the nail in the
copper doesn't get forced in. The copper will expand into the concrete walls
to hold the nail or screw. WARNING good luck getting it out if you ever
intend to, you will shear the nail before you ever pull it.