Documents disponibles écrits par cet auteur

Correcting liquefaction resistance for aged sands using measured to estimated velocity ratio / Ronald D. Andrus in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 6 (Juin 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 6 (Juin 2009) . - pp. 735–744 Titre : Correcting liquefaction resistance for aged sands using measured to estimated velocity ratio Type de document : texte imprimé Auteurs : Ronald D. Andrus, Auteur ; Hossein Hayati, Auteur ; Nisha P. Mohanan, Auteur Année de publication : 2009 Article en page(s) : pp. 735–744 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Aging  Sand  Cone  penetration  tests  Earthquakes  In  situ  tests  Soil  liquefaction  Wave  velocity  Penetration  tests Résumé : Factors for correcting liquefaction resistance for aged sands using ratios of measured to estimated shear-wave velocity (MEVR) are derived in this paper. Estimated values of shear-wave velocity (VS) are computed for 91 penetration resistance- VS data pairs using previously published relationships. Linear regression is performed on values of MEVR and corresponding average age. Age of the sand layer is taken as the time between VS measurements and initial deposition or last critical disturbance. It is found that MEVR increases by a factor of about 0.08 per log cycle of time, and time equals about 6years on average when MEVR equals 1 for the recommended penetration resistance- VS relationships. The resulting regression equation is combined with the strength gain equation reported by Hayati et al. 2008 in “Proc., Geotechnical Earthquake Engineering and Soil Dynamics IV,” to produce a MEVR versus deposit resistance correction relationship. This new corrective relationship is applied to create liquefaction resistance curves based on VS , standard penetration test blow count, and cone tip resistance for sands of various ages (or MEVRs). Because age of natural soil deposits is usually difficult to accurately determine, MEVR appears to be a promising alternative. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000025 [article] Correcting liquefaction resistance for aged sands using measured to estimated velocity ratio [texte imprimé] / Ronald D. Andrus, Auteur ; Hossein Hayati, Auteur ; Nisha P. Mohanan, Auteur . - 2009 . - pp. 735–744. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 6 (Juin 2009) . - pp. 735–744 Mots-clés : Aging  Sand  Cone  penetration  tests  Earthquakes  In  situ  tests  Soil  liquefaction  Wave  velocity  Penetration  tests Résumé : Factors for correcting liquefaction resistance for aged sands using ratios of measured to estimated shear-wave velocity (MEVR) are derived in this paper. Estimated values of shear-wave velocity (VS) are computed for 91 penetration resistance- VS data pairs using previously published relationships. Linear regression is performed on values of MEVR and corresponding average age. Age of the sand layer is taken as the time between VS measurements and initial deposition or last critical disturbance. It is found that MEVR increases by a factor of about 0.08 per log cycle of time, and time equals about 6years on average when MEVR equals 1 for the recommended penetration resistance- VS relationships. The resulting regression equation is combined with the strength gain equation reported by Hayati et al. 2008 in “Proc., Geotechnical Earthquake Engineering and Soil Dynamics IV,” to produce a MEVR versus deposit resistance correction relationship. This new corrective relationship is applied to create liquefaction resistance curves based on VS , standard penetration test blow count, and cone tip resistance for sands of various ages (or MEVRs). Because age of natural soil deposits is usually difficult to accurately determine, MEVR appears to be a promising alternative. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000025

Correcting liquefaction resistance of unsaturated soil using wave velocity / Akhter M. Hossain in Journal of geotechnical and geoenvironmental engineering, Vol. 139 N° 2 (Février 2013) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 2 (Février 2013) . - pp. 277-287 Titre : Correcting liquefaction resistance of unsaturated soil using wave velocity Type de document : texte imprimé Auteurs : Akhter M. Hossain, Auteur ; Ronald D. Andrus, Auteur ; William M. CampIII, Auteur Année de publication : 2013 Article en page(s) : pp. 277-287 Note générale : geotechnique Langues : Anglais (eng) Mots-clés : compression;  wave  velocity;  soil  liquefaction;  penetration  tests;  shear  waves;  unsaturated  soils Résumé : Explicit empirical relationships for correcting liquefaction resistance of unsaturated soil below the groundwater table using compression wave velocity (VP) and shear wave velocity (VS) are derived and evaluated in this paper. The relationships are derived using published laboratory test data for four different sands and one silt material. The laboratory test data based on VP exhibit less scatter than the test data based on the ratio VP/VS. For this reason, the VP-based relationship is recommended for correcting the liquefaction resistance of unsaturated soil. The influence of loading cycles and relative density on the recommended relationship is investigated. From a review of 40 field case history sites, it is found that in the critical layers at 20% of the sites, average VP is less than 1,400 m/s, indicating unsaturated conditions. Liquefaction resistances computed for eight field case histories with VP<1,200 m/s in the critical layers are corrected and plotted on penetration- and VS-based liquefaction evaluation charts. The results support the use of the correction for unsaturated conditions below the groundwater table. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000770 [article] Correcting liquefaction resistance of unsaturated soil using wave velocity [texte imprimé] / Akhter M. Hossain, Auteur ; Ronald D. Andrus, Auteur ; William M. CampIII, Auteur . - 2013 . - pp. 277-287. geotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 2 (Février 2013) . - pp. 277-287 Mots-clés : compression;  wave  velocity;  soil  liquefaction;  penetration  tests;  shear  waves;  unsaturated  soils Résumé : Explicit empirical relationships for correcting liquefaction resistance of unsaturated soil below the groundwater table using compression wave velocity (VP) and shear wave velocity (VS) are derived and evaluated in this paper. The relationships are derived using published laboratory test data for four different sands and one silt material. The laboratory test data based on VP exhibit less scatter than the test data based on the ratio VP/VS. For this reason, the VP-based relationship is recommended for correcting the liquefaction resistance of unsaturated soil. The influence of loading cycles and relative density on the recommended relationship is investigated. From a review of 40 field case history sites, it is found that in the critical layers at 20% of the sites, average VP is less than 1,400 m/s, indicating unsaturated conditions. Liquefaction resistances computed for eight field case histories with VP<1,200 m/s in the critical layers are corrected and plotted on penetration- and VS-based liquefaction evaluation charts. The results support the use of the correction for unsaturated conditions below the groundwater table. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000770

Liquefaction potential assessment of pleistocene beach sands near charleston, south carolina / Tahereh Heidari in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 10 (Octobre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 10 (Octobre 2012) . - pp.1196–1208. Titre : Liquefaction potential assessment of pleistocene beach sands near charleston, south carolina Type de document : texte imprimé Auteurs : Tahereh Heidari, Auteur ; Ronald D. Andrus, Auteur Année de publication : 2013 Article en page(s) : pp.1196–1208. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Aging  Cone  penetration  test  In  situ  tests  Probability  Sand  Shear  waves  Soil  liquefaction  South  Carolina Résumé : Liquefaction potential of four Pleistocene beach sand deposits in the Greater Charleston area, South Carolina, is assessed. The assessment is based on a review of 51 sites of conspicuous craterlets and horizontal ground displacement that occurred in beach sand deposits during the 1886 Charleston earthquake and an analysis of 82 seismic cone penetration tests with pore-pressure measurements. Of the 51 ground failure sites, 23 are associated with the Ten Mile Hill beds; 13 with the Wando Formation; 13 with the Silver Bluff terrace and younger deposits that lie adjacent to the harbor, rivers, and creeks; and two with the Ladson Formation. Liquefaction potential is analyzed using the seismic cone data with and without correction for age-related processes (diagenesis) and then expressed in terms of the liquefaction potential index (LPI). Probability curves are developed from the LPI calculations for different earthquake ground-shaking parameters. The probability curves for the Wando Formation overpredict liquefaction potential when no corrections for diagenesis are made. When corrections for diagenesis are made, the probability curves for all four sands generally agree with the observed field behavior. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000686 [article] Liquefaction potential assessment of pleistocene beach sands near charleston, south carolina [texte imprimé] / Tahereh Heidari, Auteur ; Ronald D. Andrus, Auteur . - 2013 . - pp.1196–1208. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 10 (Octobre 2012) . - pp.1196–1208. Mots-clés : Aging  Cone  penetration  test  In  situ  tests  Probability  Sand  Shear  waves  Soil  liquefaction  South  Carolina Résumé : Liquefaction potential of four Pleistocene beach sand deposits in the Greater Charleston area, South Carolina, is assessed. The assessment is based on a review of 51 sites of conspicuous craterlets and horizontal ground displacement that occurred in beach sand deposits during the 1886 Charleston earthquake and an analysis of 82 seismic cone penetration tests with pore-pressure measurements. Of the 51 ground failure sites, 23 are associated with the Ten Mile Hill beds; 13 with the Wando Formation; 13 with the Silver Bluff terrace and younger deposits that lie adjacent to the harbor, rivers, and creeks; and two with the Ladson Formation. Liquefaction potential is analyzed using the seismic cone data with and without correction for age-related processes (diagenesis) and then expressed in terms of the liquefaction potential index (LPI). Probability curves are developed from the LPI calculations for different earthquake ground-shaking parameters. The probability curves for the Wando Formation overpredict liquefaction potential when no corrections for diagenesis are made. When corrections for diagenesis are made, the probability curves for all four sands generally agree with the observed field behavior. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000686

Liquefaction potential map of Charleston, South Carolina based on the 1886 earthquake / Hossein Hayati in Journal of geotechnical and geoenvironmental engineering, Vol. 134 N° 6 (Juin 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 815–828 Titre : Liquefaction potential map of Charleston, South Carolina based on the 1886 earthquake Type de document : texte imprimé Auteurs : Hossein Hayati, Auteur ; Ronald D. Andrus, Auteur Année de publication : 2010 Article en page(s) : pp. 815–828 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Cone  penetration  tests  Earthquakes  Liquefaction  Mapping  Shear  waves  Velocity  South  Carolina Résumé : A liquefaction potential map of the peninsula of Charleston, S.C., is presented in this paper. Liquefaction potential is expressed in terms of the liquefaction potential index developed by Iwasaki et al. and calculated using 44 cone penetration test profiles. The cone profiles are supplemented with information from the 1:24,000 scale geologic map by Weems and Lemon, several first-hand accounts of liquefaction and ground deformation that occurred during the 1886 Charleston earthquake, and liquefaction probabilities determined by Elton and Hadj-Hamou based on standard penetration tests. Nearly all of the cases of liquefaction and ground deformation occurred in the Holocene to late Pleistocene beach deposits that flank the higher-ground sediments of the Wando Formation. To match the observed field behavior, a deposit resistance correction factor of 1.8 is applied to cyclic resistance ratios calculated for the 100,000-year -old Wando Formation. No corrections are needed for the younger deposits. In additional to 1886 field behavior, the deposit resistance corrections are supported by ratios of measured to predicted shear-wave velocity. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2881 [...] [article] Liquefaction potential map of Charleston, South Carolina based on the 1886 earthquake [texte imprimé] / Hossein Hayati, Auteur ; Ronald D. Andrus, Auteur . - 2010 . - pp. 815–828. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N° 6 (Juin 2008) . - pp. 815–828 Mots-clés : Cone  penetration  tests  Earthquakes  Liquefaction  Mapping  Shear  waves  Velocity  South  Carolina Résumé : A liquefaction potential map of the peninsula of Charleston, S.C., is presented in this paper. Liquefaction potential is expressed in terms of the liquefaction potential index developed by Iwasaki et al. and calculated using 44 cone penetration test profiles. The cone profiles are supplemented with information from the 1:24,000 scale geologic map by Weems and Lemon, several first-hand accounts of liquefaction and ground deformation that occurred during the 1886 Charleston earthquake, and liquefaction probabilities determined by Elton and Hadj-Hamou based on standard penetration tests. Nearly all of the cases of liquefaction and ground deformation occurred in the Holocene to late Pleistocene beach deposits that flank the higher-ground sediments of the Wando Formation. To match the observed field behavior, a deposit resistance correction factor of 1.8 is applied to cyclic resistance ratios calculated for the 100,000-year -old Wando Formation. No corrections are needed for the younger deposits. In additional to 1886 field behavior, the deposit resistance corrections are supported by ratios of measured to predicted shear-wave velocity. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A6%2881 [...]

Model uncertainty in normalized shear modulus and damping relationships / Zhang, Jianfeng in Journal of geotechnical and geoenvironmental engineering, Vol. 134 N°1 (Janvier 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N°1 (Janvier 2008) . - pp. 24–36 Titre : Model uncertainty in normalized shear modulus and damping relationships Type de document : texte imprimé Auteurs : Zhang, Jianfeng, Auteur ; Ronald D. Andrus, Auteur ; C. Hsein Juang, Auteur Année de publication : 2008 Article en page(s) : pp. 24–36 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Damping  Dynamic  properties  Ground  motion  Seismic  analysis  Shear  modulus  Uncertainty  principles Résumé : Model uncertainty associated with normalized shear modulus and material damping ratio relationships developed in a previous study is discussed in terms of standard deviations in this paper. The relationships were originally developed by separating resonant column and torsional shear test results of 122 specimens into three general geologic groups (Quaternary-age soils, Tertiary-age and older soils, and residual/saprolite soils) and determining mean regressional model parameters (i.e., α , k , γr1 , and Dmin1 ) for each group. Statistical variability of the regressional parameters is quantified and expressed by standard errors of prediction. The determined uncertainty of the regressional parameters is then propagated through the recommended relationships using the point-estimate method to estimate the model uncertainty of the relationships. The point-estimate method is a simple and effective method of uncertainty propagation. For uncertainty estimation, the regressional parameters are assumed to be uncorrelated for the sake of simplicity. The influence of this assumption on the model uncertainty of normalized shear modulus and material damping ratio values, as well as the sensitivity of the model uncertainty to the uncertainty of various regressional parameters, are also discussed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A1%2824 [...] [article] Model uncertainty in normalized shear modulus and damping relationships [texte imprimé] / Zhang, Jianfeng, Auteur ; Ronald D. Andrus, Auteur ; C. Hsein Juang, Auteur . - 2008 . - pp. 24–36. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 N°1 (Janvier 2008) . - pp. 24–36 Mots-clés : Damping  Dynamic  properties  Ground  motion  Seismic  analysis  Shear  modulus  Uncertainty  principles Résumé : Model uncertainty associated with normalized shear modulus and material damping ratio relationships developed in a previous study is discussed in terms of standard deviations in this paper. The relationships were originally developed by separating resonant column and torsional shear test results of 122 specimens into three general geologic groups (Quaternary-age soils, Tertiary-age and older soils, and residual/saprolite soils) and determining mean regressional model parameters (i.e., α , k , γr1 , and Dmin1 ) for each group. Statistical variability of the regressional parameters is quantified and expressed by standard errors of prediction. The determined uncertainty of the regressional parameters is then propagated through the recommended relationships using the point-estimate method to estimate the model uncertainty of the relationships. The point-estimate method is a simple and effective method of uncertainty propagation. For uncertainty estimation, the regressional parameters are assumed to be uncorrelated for the sake of simplicity. The influence of this assumption on the model uncertainty of normalized shear modulus and material damping ratio values, as well as the sensitivity of the model uncertainty to the uncertainty of various regressional parameters, are also discussed. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A1%2824 [...]

Sear-Wave Velocity and Seismic Response of Near-Surface Sediments in Charleston, South Carolina / Ronald D. Andrus in Bulletin of the seismological society of America, Vol. 96 N° 5 (Octobre 2006) 

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Updated liquefaction resistance correction factors for aged sands / Hossein Hayati in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 11 (Novembre 2009) 

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