system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Generally speaking, how do architects and engineers design multi story buildings knowing that they will withstand the weight burden?

Watching the MLB all star game and the thought occurred to me. How do we know that the upper deck of a stadium will hold the weight without collapsing?
gpt
I’ve heard it this way, you build it from the top down. Let’s say the top floor is 100 tons so the next floor down has to support that weight and is 120 tons itself. Now the floor below that has to support 220 tons, etc. 

Part of the weight of each floor is all the stuff that goes in it; furniture, people, etc and each floor is rated to support X times it’s real life load.