Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

We use 473 weak motion surface records from a relatively soft soil site (CORSSA) and 81 from a relatively stiff soil site (DIM) in conjunction with downhole records obtained in rock in order to study linear seismic soil amplification in Aegion, Greece. We estimate peak ‘soil-to-outcrop’ amplification factors in the time domain for the two sites through linear regression of PGA values. We view the results derived from these very weak motion records as indicative of the entire linear elastic range based on the large dataset size. We compare the peak horizontal soil amplification factors we derive from records with those suggested by design codes based on site classification, and find that they define lower boundaries rather than predictions of the average. We also find that, although the vertical component is assumed unamplified, both datasets show a two-fold amplification in its peak value. The results are also compared with previous finite difference analyses. For CORSSA, the amplification values calculated from 2D analyses are quite similar to those based on records, while for DIM they are 35% lower. Finally, while the elastic response spectra are well within the design spectra due to the small PGA values, we normalize them as to PGA in the context of discussing site effects. Spectral shapes do not infer strong site effects at DIM, but they do so for CORSSA, indicating strong surface waves particularly around the site’s fundamental period.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Weak Motion Linear Soil Amplification at Aegion, Greece, and Comparison with Seismic Design Codes

San Diego, California

We use 473 weak motion surface records from a relatively soft soil site (CORSSA) and 81 from a relatively stiff soil site (DIM) in conjunction with downhole records obtained in rock in order to study linear seismic soil amplification in Aegion, Greece. We estimate peak ‘soil-to-outcrop’ amplification factors in the time domain for the two sites through linear regression of PGA values. We view the results derived from these very weak motion records as indicative of the entire linear elastic range based on the large dataset size. We compare the peak horizontal soil amplification factors we derive from records with those suggested by design codes based on site classification, and find that they define lower boundaries rather than predictions of the average. We also find that, although the vertical component is assumed unamplified, both datasets show a two-fold amplification in its peak value. The results are also compared with previous finite difference analyses. For CORSSA, the amplification values calculated from 2D analyses are quite similar to those based on records, while for DIM they are 35% lower. Finally, while the elastic response spectra are well within the design spectra due to the small PGA values, we normalize them as to PGA in the context of discussing site effects. Spectral shapes do not infer strong site effects at DIM, but they do so for CORSSA, indicating strong surface waves particularly around the site’s fundamental period.