I want to suspend a concrete slab two-car garage over a two-car garage. I need to know how many beams need to be under the concrete slab, how thick the beams need to be and how thick the concrete. I will be parking two F250 ford trucks above the bottom garage each weighing 8,000 lb. what will be the total weight of the suspended floor? I will have to make special weight bearing walls to hold the concrete floor.

You need an engineer who know building coeds in your area.