So i'm looking at some technical drawings here (mechanical engineering co-op) and the live load rating is 100 pounds per square foot (PSF) for this particular drawing. My question is this: why is it so low? Just me standing with my feet together exerts roughly 230 pounds per square foot (i'm 230lbs, my feet take up ~1 square foot). The structure this drawing depicts is regularly walked on by workers and I must be misunderstanding the concept if just standing on it exceedes its designed strength. I'm just now learning about live load though google searches, seems to be more civil's field, so go easy on me lol.