Designing from first principles to control floor vibration from mechanical equipment

This presentation outlines a method for predicting floor vibration due to mechanical equipment using the structural frequency response function (FRF) and dynamic forces produced by the mechanical equipment. The goal is to develop more reliable and cost-optimizeddesigns, in contrast to conventional approaches that prescribe equipment vibration isolators based on equipment type, horsepower, and structural column spacing. Accurate structural FRF predictions are possible using finite element analysis (FEA), provided that the analysis methodology is validated against measured data from comparable existing structures. At this time, dynamic force data are generally unavailable from equipment manufacturers. However, rough estimates are possible by measuring mechanical vibration and the structural FRF of an existing installation. While this is currently a field method with several limitations, it should ultimately be developed into a standardized laboratory method manufacturers use to provide force data. With increasing construction costs and a trend toward placing mechanical equipment near vibration sensitive areas, there is now an opportunity to use experimental and analytical methods to optimize designs rather than relying on generic approaches that can be overly conservative or miss important details.