As dbuzz and Lufti mentioned vibration isolators might help. They would attenuate some of the higher frequency vibrations in the equipment that pass from the machinery into the structure. Much of the energy however is in the lower frequencies and is much more difficult to control. These vibrations require springs with larger deflections than is usually practical.
I was involved with a problem like this with a rooftop HVAC system where vendors and a vibration consultant were called in. Some improvements were made but what was really needed was judged to be too expensive by management.
That's not to say your problem can't be corrected however, but you might need to contact an experienced engineer in this field for an onsite visit. It depends on the details. The machinery, structural support, maintenance, etc.
Good Luck,
-Mike