High frequency calibration of a finite element model of an irregular building via ambient vibration measurements

An effective approach for calibration of a finite element (FE) model for analysis of existing structure consists of matching the frequencies with measured several fundamental frequencies in the corresponding full-scale structure. Implicit in this approach is the assumption that the response is dominated by the modes and frequencies of the structural system as a whole, and thus a scant attention has generally been paid to the vibration of slabs and terraces or various other structural components and attachments. In this paper we show that many such mode shapes associated with vertical vibration do occur in the frequency range of interest for analyses of earthquake response (in this paper we consider only the frequencies up to 50 Hz) and hence should be included in the dynamic response calculations. We show how the vertical vibrations of terraces and floor slabs in a building can be used to verify and tune its finite element (FE) model up to high frequencies. The new approach we introduce in this paper will work in all structures with floor slabs that are excited by vertical microtremor noise and by slab vibrations induced by deformation of beams and columns, which support them.