Optimal Duration of Observations During Seismic Inspection of Buildings

Studying the nature of the occurrence and propagation of microseismic tremors has not lost its relevance over the past few decades. Currently, the analysis of microseisms is the basis of some engineering and geological studies, including those aimed at the inspection of structures of various purposes. The procedure for preparing and conducting surveys is governed by a system of regulatory documents. However, the current codes and specifications represent a general guide for assessing the operational properties of building structures. Therefore, specific survey methods need to be clarified and detailed. Describes the experiment of examining the building regarding the dynamics of frequency characteristics within 24 hours. The observation system was implemented in the form of 16 points, evenly distributed over the volume of the building. Spectral analysis based on FFT was carried out to identify the time intervals within the 24-hour period with a pronounced maximum and minimum level of man-induced impact on the studied subject. During the hours of maximum exposure, the spectra were correlated according to records of different duration in terms of the correspondence of frequency components. The necessary and sufficient duration of registration of microseismic vibrations was derived to determine the frequency of natural vibration of a building when the observation points are located on the lower and upper floors.