I am aware of a testing program done by the Structural Safety Section of
the Office of the State Architect of California (now DSA) which weighed
standard and oversized books on standard 7 1/2 foot shelving with seven
shelves per side. The program determined 25 pounds per running foot of
standard shelving was realistic. The load per foot of a stack is 25X14
shelves or 350 pounds per foot and is distributed over a 21 inch (1.75
feet) floor space. The shelf stacks are separated by 36 inch wide stack
aisles. Periodic cross aisles provide access to the stack aisles.To
substantiate the specified stack loading of 125 psf in the code at that
time, this rational was used:
350 pounds per foot divided by 1.75 feet gives a net stack load of 200 psf.
The stacks occupy about 1/3 of the total floor area(67.5 psf).The remaining
57.5 psf was allocated to ordinary transient live load.
I have also heard of a load of 40 pounds per cubic foot used with a 7 1/2
Michael Krakower SE