Latest issueFrequency-dependent Response of Soft (Sandy and Loess) Soils in Seismic Motion and Seismic Rigidity Method
DOI: 10.37153/2618-9283-2020-1-53-62
Authors:
Elena V. Deshcherevskaya
senior researcher, The Schmidt Institute of Physics of the Earth, The Russian Academy of Sciences (IPE RAS), Moscow, Russian Federation
Dr. of Sci. (Phys. and Math.), Head of the Laboratory of Engineering Seismology and Interpretation of Seismic Observations No. 306, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. Moscow, Russian Federation
Olga V. Pavlenko
Rubric: Seismic zoning
Key words: soil response, response spectra, seismic rigidity method (MSG)
Annotation:
With this work, we start studying of the response of soils of various types (among 11 types of the most representative surface soils on the territory of Russian Federation) in seismic motion, based on in situ observations (KiK-net data). The response of soft sandy and loess soils to weak and medium-intensity seismic motion is analyzed. We show that the response of rather homogeneous soil profiles (without clear seismic boundaries) to seismic motion is frequency-dependent and contains resonant frequencies, at which seismic motion is noticeably enhanced. At stronger seismic motion, the resonant frequencies are reduced, and the amplification of seismic motion by soil layers is also reduced. These effects are not taken into account in seismic rigidity method, the application of which is still required by the Building codes acting in Russia. We should change the practice of application of the seismic rigidity method in the Building codes, by clearly defining the scope of the method, and we should move to the spectral description of the corrections for ground conditions in earthquake resistant construction, by means of response spectra, as done in other countries.