ASCE 7-02 lists live loads for libraries - including stack rooms. Include these in your analysis. Also, make sure you "batten down the hatches" regarding making sure the books don't fall on someone in the event of an earthquake.
ASCE 7-02 gives the library live load as 150 psf for stack rooms. Section 9.5.3, definition of W, the effective weight of the structure including the total dead load and other loads listed below: In storage areas, a min of 25% of the floor live load. Actual partition weight or 10 psf, whichever is greater. Total operating weight of permanent equipment. 20% of flat roof snow if loads exceed 30 psf.
If library stack room is considered storage, then I would use 25% of 150 psf in the effective seismic weight. However, I can see that, with the stacks full, this might be unconservative, especially if bolted to the floor. Before I run loads on the building, I just want to be sure that I should include 100% of the live load for library stacks for the effective seismic weight. This will make a large difference in the design, although I'm probably in SDC B.
Though California Building Code may not be applicable where your project is located... 2001 CBC Table 16A-B Footnote 12 covers various stack loading categorized by type (paper media, film media and others) and shelf size. I don't think IBC outlined the design stack loading in detail yet.
