Not quite sure what a wooden floor member is but we are assuming you mean a floorboard. Use a tennon saw or wide, very sharp chislel if you only have one to do. If you have lots we would suggest buying a cheap Aligator, or Reciprocating saw. If you look in our project on replacing timber floors you will see all the equipent you need.
Are you talking about your floor boards or floor JOISTS. If you are planning to remove your joists be advised that if the structure is a timber frame your walls may be supported on these joists too.
If not then I suggest use a saw that you dont mind blunting a few forward teeth off to partialy cut through the joist. As you near the bottom of the joist hammer a wedge of wood either side of the cut to raise it off the concrete then continue to saw or chisel through.