SEISMIC INTERFEROMETRY TECHNIQUE FOR BUILDING MONITORING: A COMPUTATIONAL METHOD TO DETERMINE DYNAMIC PARAMETERS

Resumo

Seismic interferometry applied to environmental vibration data is an advantageous strategy
used to verify structures responses, especially regarding to continuous data logging and in situations
where it is not practical or even unsafe, to allocate dynamic sources. Its application yields important
information about mechanical properties and discontinuities of the medium, since the produced waves
establishes an elastic response regarding the medium in which it propagates. The analysis, after the
monitoring procedure, consisted in an application of a computational technique known as
“deconvolution” of environmental-vibration records to obtain traveling waves and extract the natural
frequency due to the linear response of the building, from peaks of the average power spectrum of
these deconvolved waves. As application, the environmental noise propagated in a five-story building
located at Federal University of Rio Grande do Norte was studied to obtain responses of frequencies.
Accelerometers localized on the floors of the building registered the environmental noise along some
days and, consequently, made it possible to observe the relation between human and environmental
activities and the oscillation amplitude of the signal. To confirm these values, a computational
mathematical model of the building was built, using a commercial software, in order to obtain the
numerical natural frequencies. At last, a critical analysis of the results is performed.