To reduce vibration transmission, we use “Vibration Isolators” which is the use of a resilient material between structure and machine. When dealing with earthquakes, the floor moves horizontally and vertically in random directions through range of frequencies. If the floor frequency was very high compare with isolation system, the machine would be isolated and remain motionless in space.
If the floor frequency was very low, the machine would move with the structure. During most seismic events, the range of input frequencies includes the system resonance so that the isolation springs act as amplifier with the machine to develop enough motion to damage or fly free of the springs.
This problem has been recognized for quite some time, but until very recently the criteria for the restraint of these machines generally came from the Uniform Building Code.
Snubbers from Mason Industries, Inc (USA) are designed to provide all-directional restraints to vibration isolated machines or equipment against loads from earthquakes. Typical models are: Z-1011 and Z-1225.
|Z - 1011
||Z - 1225