On the processing of earthquake-induced structural response signals by suitable Operational Modal Analysis identification techniques

In the present study, two different Operational Modal Analysis (OMA) techniques, namely a refined Frequency Domain Decomposition (rFDD) and an improved Data-Driven Stochastic Subspace Identification (SSI-DATA), are specifically conceived towards assessing current modal dynamic properties of buildings under seismic excitation and simultaneous heavy damping (in terms of identification challenge). Synthetic earthquake-induced response signals, generated from a set of different frame structures and earthquake baseexcitations, have been investigated, in order to make a serious step forward in assessing the OMA effectiveness of the two techniques at seismic response input. According to the present investigation, best up-to-date, re-interpreted, output-only algorithms may be effectively used to characterize the current dynamic behaviour of structures and to identify potential structural modifications along the experienced seismic histories, thus allowing for possible Structural Health Monitoring approaches in the Earthquake Engineering range.