Site Response Analysis for “Side” Soil Profiles
Site Response Analysis for “Side” Soil Profiles

Site Response Analysis for “Side” Soil Profiles

DOI: 10.37153/2618-9283-2020-1-11-17

Authors:  

Тяпин Александр Георгиевич Tyapin A.G.
Dr.Sci.Tech., JSC Atomenergoproject. Moscow, Russian Federation

Antonov N.A.
канд. техн. наук, АО «Атомэнергопроект» (г. Москва)


Rubric:     Theoretical and experimental studies   
Key words: site response analysis (SRA), best estimate (BE), upper boundary (UB) and lower boundary (LB) soil profiles, foundation input response spectra (FIRS)
Annotation:
The authors suggest a new procedure of Site Response Analysis (SRA) for the so-called “side” (or additional) soil profiles – Low Boundary (LB) and Upper Boundary (UB). Standards require the analyses of these profiles in addition to the Best Estimate profile (BE) to account for the uncertainty in the input data about soil properties. The authors suggest stopping using the same input time history for all three profiles as a control motion at the surface, because it corresponds to the different physical seismic excitations coming form the depth. This is not in line with the ideology of Standards. Instead the authors suggest using the same time history as a control motion at the outcropped surface of the underlying half-space. This is also not completely correct, because for these three profiles (BE, UB and LB) the underlying half-spaces are also different. However, due to the physical considerations if all half-spaces are stiff enough, the error should not be so important. The effect of the 
proposed change is demonstrated on a particular site. The changes in the velocity and damping profiles have proved to be negligible, but the difference in the resulting response spectra at the outcropped surface of the foundation mat has proved to be significant. Generally, the response spectra for the “side” profiles came closer to spectrum for the BE profile. This result reflects the real world logic.

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