I plan on placing two cars on a 100mm thick concrete floor reinforced by OD8mm steel rods (gridded at 200mm distance between rods). Surrounding support pillars are also reinforced by 2*OD20mm + 3*OD18mm steel rods. See below blueprint and car/weight spreading original idea.
Two cars = 4,000KG and spaced, to me, adequately. Well... adequately, this is where it gets complicated for me. There are ppl on the first floor and I need to mathematically prove that this project is not going to become a catastrophe (I mean, for someone's head, downstairs).
Anyone here who is a licensed structural engineer that could quickly run this in his/her FREE calculator for a fella member? A member who is too cheap (or embarrassed) to seek assistance from a specialized firm.
At the moment I just need a general advice based on "General Data" as-in, using the lowest tensile, yield and compressive strength, elastic modulus of construction concrete, etc.... it's not granite I reassure you (viva China!). Once I have a good idea, I'll then go spend the $ it takes RE seeking assistance from a licensed firm to issue the simulation (legal, need to pay for stuff like that unfortunately)
Anybody here can't tell me if I am completely wasting my time, or being a "public danger"?!

^ framed in that picture is the exact area/under view of the floor I intent loading. Right down to the clock on the wall
ps. there are a lot of spiders and 'webs' on that ceiling. Can this be added as a contributing factor to strength in this case?