RANDOM VIBRATION ANALYSIS OF OFFICE AND RESIDENTIAL FLOORS SUBMITTED TO WALKING PERSONS

To avoid annoying vibration of office and residence floors, codes usually state that the first natural frequency of each panel should be at least 6 Hz; this concept has lately become a sort of taboo for structural engineers. However, in many cases panels have a natural frequency below (even much below) that limit; it is then necessary, in order to comply with the codes, to increase the frequency by acting on the mass and/or stiffness, or to add tuned-mass dampers. Before resorting to these measures, that may prove difficult and expensive, it is advisable to first perform a vibration analysis of the floor and to assess the vertical accelerations induced by walking persons; codes provide upper limits for these accelerations. The present paper presents a methodology based on the Monte Carlo Method in which the vibration is simulated in a finite- elements model. A numerical example illustrates the proposed methodology through the analysis of a floor with a 2.9 Hz first natural frequency.