Floor Load Guidelines For Second Floor Bookcases

I am considering moving a large number of books in bookcases to a second floor room, and I am confused by the application of live load to this situation.

Each case has a 2.3 square foot footprint, and I believe a reasonable estimate of their filled mass would be 350 lbs each, for a load of about 150 lb/square foot. Six such cases would be placed in a line next to, but not attached to, a load bearing wall (the separating wall of a townhouse construction.)

I do not have access to the original plan of my home, however I am aware that in Illinois the minimum live load would be a mere 40 lb/square foot. The home was built in the mid 1980s.

My related questions are:

1) Am I applying the live load formula correctly? I can multiply and divide and get the pressure of the footprint trivially, but is that all there is to it? A full bookcase exceeds load guidelines by nearly a factor of four? This contradicts my intuition-- how does anyone in the United States put bookshelves in a second floor apartment?

2) What are reasonable guidelines for second or more story book storage?

UPDATE

• I neglected to mention, the room is a balcony/loft
• Dimensions: Roughly 15' x 15' plus attached utility closet; see scale drawing
• Note the wall on the east is the one I sincerely hope to be load-bearing, as it is the separator between my neighbor and I.
• Note the dotted line indicating the edge of the loft, and Note there are no support columns or walls under the edge of that loft. This is what has me somewhat twitchy.
• Total estimated weight would be roughly: 3000 lbs bookcases, 300 lbs washer/dryer set in utility closet, 300 lbs two easy chairs and coffee table, 200 lbs one adult = 3800 lbs. That is a very conservative estimate assuming a planned upgrade to sturdier bookcases, some fairly heavy chairs, and includes the load of the washer/dryer for good measure.
• The unit itself is a two story townhome with additional units to the east and west, circa 1985 construction.

• Are you putting the bookcase in the middle of the floor or against a wall? If against a wall, can you sort out if it is a bearing or non bearing wall? And is it a single family home or an apartment, different codes to go by I think.... – Jack Feb 25 '18 at 22:29
• How many square feet is the room? What will be total load in the room including bookshelves, furniture, aquariums, people, elephamts etc.? – Harper Feb 25 '18 at 22:55
• @Jack definitely against a wall, working on sorting out the load-bearing wall issue. It's not obvious by sight. Dwelling is a single unit in a townhouse, and the wall separates my unit from my neighbor's. – Reader Feb 25 '18 at 22:58
• @harper I will measure and update later tonight, including answers to jack. Total load, however, will depend on what I learn here. – Reader Feb 25 '18 at 23:11
• If it is up against a bearing wall, how much weight you put in it will not be an issue, so placement in a room is everything.... – Jack Feb 26 '18 at 1:07