Racks installed above ground level are prone to a DAF (Dynamic Amplification Factor) during seismic events. Great care must be taken to provide load capacity depending on the building and seismic zone. When determining load capacity, you should ask the building engineer to provide the DAF to use in the analysis of the rack. Below are the references to Canadian and American rack design codes on the subject.
"Storage racks located at levels above the grade elevation shall be designed to resist design seismic forces that consider the responses of the building and storage racks as a combined structure to seismic ground motion." Taken from: CAN/CSA A344.2-05 Standard for the design and construction of steel storage racks.
"Storage racks installed at elevations above grade shall be designed, fabricated and installed with the following requirements: Storage racks shall meet the force and displacement requirements required of non-building structures supported by other structures, including the force and displacement effects caused by amplifications of upper-story motions." Taken from: ANSI MH16.1 (2012) 2.6.2 Above-Grade Elevation.