K. K. Antonov learn about concrete plate and giant loads acting. If you have 0.5 ton / sq.meter and change to 1.5 ton / sq.meter of load, then, your concrete plate slab have only 5.1% of depth h dimension addition. What kind of machinery you use (tire or chain ?). I made industrial concrete plates with high loads (1/2 to 3/4 of your load), I used two way slabs, with orthogonal beams spaced under the slab. See Design of Reinforced Concrete Structures by Murashev, Sigalov and Baikov. I don't know the ACI standards equivalent to the Russian rules. I live in Brasil, south America. Atention !!! Be careful with the loads in columns under this kind of load.