I am not aware of any guidelines, other than support all the weight and make sure it has a load path. Typically i calculate by hand what the true dead load is (true!) and then determine what sort of realistic live load will be experienced. are the occupants ever going to load the floor w/ 40 psf? no. .Use some realistic load to account for that. and then a "feel-good" load based on your assumptions.
- 5 people in one room at 200 pounds each is 1000 pounds; that in a room of 12'x10' is only 8.3 psf... so you see what i mean for realistic live loads.
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Make sure you can get that load down to the earth... for underpinning we typically work in 4'-6' spaces where that amount is unsupported, repaired, loaded, then go to next 5' long area... or do 5' every 15 feet so there are 10' Original conditions between work sites.