Frequency Content Of Vibrations Research Articles

Near-field frequency attenuation of vibrations from blasting using a full-field solution

This study analyses the frequency content of vibrations from blasting in the near field using a vibration prediction model called full-field solution (FFS). For that purpose, the frequency content of recorded signals and synthetic waveforms obtained through the FFS using dominant and mean frequencies have been compared and correlated with the geometrical distance to the blastholes. The study shows that the model overestimates the dominant and mean frequencies in the entire frequency domain, which may require tailoring the source function to a lower frequency content. However, it attenuates the frequency content as distance increases. Additionally, the study shows that the mean frequencies may be used as a better estimator of the frequency content than the dominant frequencies.

Specifics of seismicity manifestations in the construction area of olympic games engineering structures in Imeretinskaya Depression, Sochi

Geological and geotechnical conditions in Imeretinskaya Depression, where Olympic Game facilities will be constructed, have some features not typical of other parts of the Great Sochi. These include the large thickness (up to 70–100 m) of Quaternary marine and alluvial deposits, overlying half-rocks and hard rocks, as well as a wide occurrence of soils of II–III and III category in terms of seismic properties. These factors, along with the high seismicity of the area, require one who determines the quantitative characteristics of seismic impacts, to take into account both the features of geological structure and properties of soils and the effect of both nearby and relatively remote earthquake sources on the magnitude and the frequency content of vibrations. Two geotechnically unfavorable sections within Imeretinskaya depression with poor data on the seismic properties of rocks throughout the depth of the Quaternary strata are used as examples to demonstrate the methodological approaches to evaluating the characteristics of seismic impacts. In conclusion, proposals regarding experimental verification of the obtained results are formulated and recommendations are given regarding the improvement of the properties of foundation soils on which earthquake induced accelerations under natural conditions reach 300–450 cm/s2.

Building vibrations and dynamic pavement loads induced by transit buses

The purpose of this study was to investigate the effect of bus suspension systems on building vibrations and dynamic pavement loads. Building vibrations and pavement loads induced by two instrumented buses having different characteristics were measured simultaneously under controlled field conditions. Field tests were performed at several vehicle speeds, normal and reduced tire pressures, and with roads having good surface condition as well as abrupt surface irregularities. Tests were carried out at two vibration complaint sites in Montréal. The level and frequency content of vibrations and loads induced by the two buses were evaluated and compared. The results show that the dynamic component of pavement loads induced by the two buses were significantly different but the difference in building vibration levels was not as significant.