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I have a question about the mezzanine floor (30ft x 24ft, 4" NWC /3"
Composite Metal Deck/W18's at 8' OC) I am designing, for  mechanical
equipment (air handlers 250, 500 and 1000CFM).  For floor vibrations
induced due to human activity, AISC Steel Design Guide No. 11 can be
used.  I am wondering if there is a similar source of info for vibrations
induced due to mechanical equipment.
Talking with the manufacturers of the air handlers and the vibration
isolators to be used, I am told that the vibration isolator mfr will design the
isolators so that the floor vibration will not be a problem.  A relatively stiff
floor (deflections < typical code limitations) should be provided.  In fact if
the floor appears to be too flexible, the vibration isolator mfr will inform
appropriate parties involved as per their standard practice.  In the
absence of vibration isolators I would try to keep the frequencies of the
equipment far apart from the floor natural frequency as possible to avoid
resonance.  I am wondering if I do not need to be concerned with floor
vibration if vibration isolators are used.  Do they completely filter out
vibration transmittal to the floor.
AISC Guide No. 11 does talk about isolators.  My reading is that they do
work but there is no assurance.
In the meantime I am going to rely on following criteria to minimize floor
vibration:  Deep stiff beams (Depth = L/20) for deflection control.
Seismic Spring Vibration Isolators with 2" vertical spring deflection. 
Concrete floor with reinforcement (I am not counting on deck composite
action because it may be lost in floor vibration).  I will review shop
drawings along with calculations performed by the isolator mfr to see if it
tells me something important.
I would like to know how you would approach this.  Thanks a lot in
advance for sharing your experience.

Vinod Sahni, SE

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