Site Response Characteristics of Compacted Gravel Fill in Iceland
Local site conditions can greatly increase the intensity and character of earthquake shaking and, thus, the extent and type of structural damage. The removal and replacement of in-situ soils with compacted gravel-sized volcanic rock has been prevalent in the Icelandic foundation subgrade constructio...
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ftvirginiatec:oai:vtechworks.lib.vt.edu:10919/91392 2024-05-19T07:42:38+00:00 Site Response Characteristics of Compacted Gravel Fill in Iceland Kennedy, Thomas John Civil and Environmental Engineering Green, Russell A. Chapman, Martin C. Rodriguez-Marek, Adrian 2019-07-09 ETD application/pdf http://hdl.handle.net/10919/91392 unknown Virginia Tech vt_gsexam:21399 http://hdl.handle.net/10919/91392 In Copyright http://rightsstatements.org/vocab/InC/1.0/ H/V Spectral Ratio Site Effects Site Response Characteristics Microtremor Iceland Thesis 2019 ftvirginiatec 2024-05-01T00:45:45Z Local site conditions can greatly increase the intensity and character of earthquake shaking and, thus, the extent and type of structural damage. The removal and replacement of in-situ soils with compacted gravel-sized volcanic rock has been prevalent in the Icelandic foundation subgrade construction practice for decades, despite the unknown seismic site response characteristics of the fill (e.g., the predominant frequency and relative site amplification). To fill this knowledge gap, over 500 hours of microtremor measurements were made at six study sites located throughout the Reykjavk, Iceland, capital region. Measurements recorded at various construction stages (e.g., the in-situ or pre-excavation, post-excavation, intermediate grades, and final grade) reveal the change in site response characteristics before and after gravel fill placement. The data was analyzed using the horizontal-to-vertical spectral ratio (HVSR) technique over a bandwidth of 0.3 to 25 Hz. Generally, the pre-excavation condition had a predominant site frequency between 3.5 and 7 Hz with relative amplification between 3.8 and 3.9 times. The placement of gravel fill atop dense to very dense silty sand underlain by bedrock shifts the predominant frequency between 10 and 16 Hz with a relative peak amplification between 2.5 and 5.3 times, generally increasing with fill thickness. Fill underlain by undulating lava rock also results in a higher a predominant frequency between 9 and 10.5 Hz, but little change in relative site amplification occurred at these frequencies (between 0.95 and 1.2 times). This dissimilarity is due to the unique lava rock HVSR signatures which have large amplification values (between 2.6 to 3.9 times) throughout the high-band frequency range. Additional investigations of sites underlain by lava rock are required to draw stronger empirical trends. The data set produced by this study can serve as a useful tool for the local geotechnical and seismological communities to mitigate seismic risk for the capital region. Master ... Thesis Iceland VTechWorks (VirginiaTech) |
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topic |
H/V Spectral Ratio Site Effects Site Response Characteristics Microtremor Iceland |
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H/V Spectral Ratio Site Effects Site Response Characteristics Microtremor Iceland Kennedy, Thomas John Site Response Characteristics of Compacted Gravel Fill in Iceland |
topic_facet |
H/V Spectral Ratio Site Effects Site Response Characteristics Microtremor Iceland |
description |
Local site conditions can greatly increase the intensity and character of earthquake shaking and, thus, the extent and type of structural damage. The removal and replacement of in-situ soils with compacted gravel-sized volcanic rock has been prevalent in the Icelandic foundation subgrade construction practice for decades, despite the unknown seismic site response characteristics of the fill (e.g., the predominant frequency and relative site amplification). To fill this knowledge gap, over 500 hours of microtremor measurements were made at six study sites located throughout the Reykjavk, Iceland, capital region. Measurements recorded at various construction stages (e.g., the in-situ or pre-excavation, post-excavation, intermediate grades, and final grade) reveal the change in site response characteristics before and after gravel fill placement. The data was analyzed using the horizontal-to-vertical spectral ratio (HVSR) technique over a bandwidth of 0.3 to 25 Hz. Generally, the pre-excavation condition had a predominant site frequency between 3.5 and 7 Hz with relative amplification between 3.8 and 3.9 times. The placement of gravel fill atop dense to very dense silty sand underlain by bedrock shifts the predominant frequency between 10 and 16 Hz with a relative peak amplification between 2.5 and 5.3 times, generally increasing with fill thickness. Fill underlain by undulating lava rock also results in a higher a predominant frequency between 9 and 10.5 Hz, but little change in relative site amplification occurred at these frequencies (between 0.95 and 1.2 times). This dissimilarity is due to the unique lava rock HVSR signatures which have large amplification values (between 2.6 to 3.9 times) throughout the high-band frequency range. Additional investigations of sites underlain by lava rock are required to draw stronger empirical trends. The data set produced by this study can serve as a useful tool for the local geotechnical and seismological communities to mitigate seismic risk for the capital region. Master ... |
author2 |
Civil and Environmental Engineering Green, Russell A. Chapman, Martin C. Rodriguez-Marek, Adrian |
format |
Thesis |
author |
Kennedy, Thomas John |
author_facet |
Kennedy, Thomas John |
author_sort |
Kennedy, Thomas John |
title |
Site Response Characteristics of Compacted Gravel Fill in Iceland |
title_short |
Site Response Characteristics of Compacted Gravel Fill in Iceland |
title_full |
Site Response Characteristics of Compacted Gravel Fill in Iceland |
title_fullStr |
Site Response Characteristics of Compacted Gravel Fill in Iceland |
title_full_unstemmed |
Site Response Characteristics of Compacted Gravel Fill in Iceland |
title_sort |
site response characteristics of compacted gravel fill in iceland |
publisher |
Virginia Tech |
publishDate |
2019 |
url |
http://hdl.handle.net/10919/91392 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
vt_gsexam:21399 http://hdl.handle.net/10919/91392 |
op_rights |
In Copyright http://rightsstatements.org/vocab/InC/1.0/ |
_version_ |
1799482331993473024 |