Razcob;
I'm not an engineer, but I do sell safes, heavy safes. The lightest standard home use gun safe I carry weighs 1100 lbs. And yes, that weight is frequently a major concern for people who do not wish to locate their new safe either in the basement, or in the garage.
All of the suggestions involving a floor jack, shoring, piers, etc. are correct. It's also possible, depending upon your home's decor, to place an 1/8" steel plate under the carpet & spread the load in that fashion. Keep in mind that the weight of the plate itself has to be factored in AND you still can't place the safe in mid-span.
If you wish to put your safe in the basement, there are a couple of other things to keep in mind. However, if you've got an RSC, the following is just for entertainment value, as RCS's are lightweights. Inspect and support your stair stringers. Even though good stair walkers will spread the load over 2 to 4 steps, the stringers are the weak point. Make absolutely sure you have the necessary manuvering room to break the load back at the head of the stairs & turn, if needed, at the bottom. Check your overhead clearences first, usually this is only a concern with 72" tall units, but we've encountered some fairly strange construction in the past.
900F