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

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 [...]

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

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 11 (Novembre 2009) . - pp. 1683–1692 Titre : Updated liquefaction resistance correction factors for aged sands Type de document : texte imprimé Auteurs : Hossein Hayati, Auteur ; Ronald D. Andrus, Auteur Année de publication : 2009 Article en page(s) : pp. 1683–1692 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : AgingCone  penetration  testEarthquakesSoil  liquefactionShear  wavesVelocityPenetration  tests Résumé : Data from over 30 sites in 5 countries are analyzed to develop updated factors for correcting liquefaction resistance for aged sand deposits. Results of cyclic laboratory tests on relatively undisturbed and reconstituted specimens suggest an increase in the correction factors of 0.12 per log cycle of time and an average reference age of 2 days for the reconstitute specimens. Laboratory and field test results combined with cyclic resistance ratio (CRR) charts suggest an increase in the correction factors of 0.13 per log cycle of time and an average reference age of 23 years. A reference age of 23 years seems appropriate for the commonly used CRR charts derived from field liquefaction and no liquefaction case history data. Because age of natural deposits is often difficult to accurately determine, a relationship between measured to estimated shear-wave velocity ratio (MEVR) and liquefaction resistance correction factor is also derived directly from the compiled data. This new MEVR-liquefaction resistance correction factor relationship is not as sensitive to MEVR as in the relationship derived indirectly in a previous paper. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000118 [article] Updated liquefaction resistance correction factors for aged sands [texte imprimé] / Hossein Hayati, Auteur ; Ronald D. Andrus, Auteur . - 2009 . - pp. 1683–1692. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 11 (Novembre 2009) . - pp. 1683–1692 Mots-clés : AgingCone  penetration  testEarthquakesSoil  liquefactionShear  wavesVelocityPenetration  tests Résumé : Data from over 30 sites in 5 countries are analyzed to develop updated factors for correcting liquefaction resistance for aged sand deposits. Results of cyclic laboratory tests on relatively undisturbed and reconstituted specimens suggest an increase in the correction factors of 0.12 per log cycle of time and an average reference age of 2 days for the reconstitute specimens. Laboratory and field test results combined with cyclic resistance ratio (CRR) charts suggest an increase in the correction factors of 0.13 per log cycle of time and an average reference age of 23 years. A reference age of 23 years seems appropriate for the commonly used CRR charts derived from field liquefaction and no liquefaction case history data. Because age of natural deposits is often difficult to accurately determine, a relationship between measured to estimated shear-wave velocity ratio (MEVR) and liquefaction resistance correction factor is also derived directly from the compiled data. This new MEVR-liquefaction resistance correction factor relationship is not as sensitive to MEVR as in the relationship derived indirectly in a previous paper. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000118