SEISMIC RESPONSE ANALYSIS FOR RAISED ACCESS FLOOR AND COMPUTER EQUIPMENT SYSTEMS CONSIDERING VERTICAL GROUND MOTIONS
The damage and failure of computer equipment typically supported by raised access floors in critical data processing facilities could have serious safety and economic implications. Current design provisions provide general guidance on how to estimate the seismic demand on non-structural elements within a structure. However, the possible lack of conservatism is of particular concern at locations near active faults where the vertical ground motion components have high amplitudes. Through reduced-order simplified modeling of a frame building and its raised access floors and computer equipment, findings are presented on the insufficiencies of current industrial spectra considering a suite of risk-targeted ground motions with both vertical and horizontal components. Excessive seismic axial force demands are found for both access floors and computer equipment. This investigation concludes that caution should be taken for seismic qualification and design of raised access floor and computer equipment systems considering vertical ground motions.