Raised access floors play a critical role in modern cleanroom design. They have unique mechanical properties that make them respond to dynamic loading in a manner quite different from conventional floors. For example, an unbraced floor is much more flexible horizontally than in the vertical direction. Horizontal vibration amplitudes with walker excitation may exceed 100 micrometers/s in an unbraced floor, exceeding the sensitivity of 1000x inspection microscopes by as much as an order of magnitude. Issues such as these become important when moderately vibration-sensitive instruments, such as optical microscopes, are supported on access floors, typically the case in cleanrooms. This paper presents results of experimental studies involving a 3m x 3m segment of floor and a large floor installed in a cleanroom, both of which were subjected to dynamic loads using a shaker. Both drive-point and propagation properties were examined. In addition, data are presented for variations in bracing and bolting using the 3m x 3m segment.
H. Amick, M. Gendreau, and C. G. Gordon, “Vibrations of Raised Access Floors,” Invited Paper, presented at the First Pan-American/Iberian Meeting on Acoustics; 144th Meeting of the Acoustical Society of America, Cancun, Mexico, 2 December 200212323b8308fe1c9988f6644cfb5cff97