Analysis of Recorded Earthquake Responses of a High-Rise Building Based on Engineering Seismometric Observations

Abstract

The article presents the results from a study of dynamic characteristics of the response of a high-rise building under the seismic impact of a series of southern Baikal earthquakes in 2007–2008. One earthquake used in the study, the Kultuk, occurred on August 27, 2008, at 10:35 LT (UTC +8). The epicenter of tremors was at the bottom of Lake Baikal, 30 km from Baikalsk, 75 km south of Irkutsk. The data were obtained by an engineering seismometric station installed on a large-panel nine-story building of the 135 series. The station consists of a 16-channel 24-bit digital-to-analog converter, 5 OSP-2M two-component accelerometers installed in the basement and on the third, fifth, seventh, and ninth floors of the building, and two SK-1P seismic sensors installed in the basement and on the ninth floor. The paper compares the peak ground acceleration values at the levels of the basement and ninth floor. The relative amplification of the acceleration amplitudes of the ninth floor with respect to the base are obtained, while it is noted that the time references of peak ground accelerations do not correlate with each other. Further study of the vibration acceleration waveforms using wavelet analysis showed that the energy of forced vibrations of the building under seismic action is redistributed from higher frequencies towards low-frequency range, close to the eigenfrequencies of the building vibrations. Based on the obtained vibration spectrograms, the frequency–amplitude gains of the building’s response to seismic events were calculated for various altitude levels. The maximum gain for the ninth floor is 17 units at the eigenfrequency of the building.