Floor vibrations and elevated non-structural masses

Vibration performance of floors in buildings is an issue to consider if vibration sources (internal or external) can cause resonant action and behavior. Modal properties of floors are some of the parameters that determine how a floor reacts when exposed to vibration excitation. On floors in buildings, usually furniture will be present. The mass of furniture on a floor (an added non-structural mass) will influence the natural frequencies of the combined furniture–floor system, and hence how the floor will respond when exposed to vibration excitation. Employing a finite-element model and Monte Carlo simulation, the paper predicts the stochastic nature of floor frequencies for a concrete floor carrying different configurations of non-structural masses. Since in reality, centers of gravity of non-structural masses (furniture) are elevated above the horizontal floor plane, this elevation of mass is implemented in the finite-element model and hence in the predictions of floor frequencies. Other differences in the assumed configuration of the non-structural masses is considered in order to allow comparison between influences of different assumptions.