So, I stacked some washers, and used a nut and a breaker bar and began to torque down on it. Tension left and the nut is spinning around, and I can't back off the nut and I can't remove the washers nor the stud. There's still pressure between the washers and the nut. Any ideas how to get this thing off?

nut cracker, grinder, apply preasure under the nut and spin it. i usually use old rocker or rod nuts and use moly lube and only pull 2 or 3 studs before getting another nut.