I just completed a similar size building, in Southern NJ
40 x 60 x12H. (3), 10 x 10 overhead doors, 2 windows and a main door 6" 4500 PSI slab.
With foam insulation in the roof, but no other options 35, 500 which was the best of 4 quotes. This was on my prepared, flat and clear pad. I paid the...