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Centrifuge testing to evaluate and mitigate liquefaction-induced building settlement mechanisms / Shideh Dashti in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 918-929 Titre : Centrifuge testing to evaluate and mitigate liquefaction-induced building settlement mechanisms Type de document : texte imprimé Auteurs : Shideh Dashti, Auteur ; Bray, Jonathan D., Auteur ; Juan M. Pestana, Auteur Année de publication : 2010 Article en page(s) : pp. 918-929 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Centrifuge  Earthquakes  Liquefaction  Mitigation  Settlement  Shallow  foundation  Soil  structure  interaction Résumé : The effective application of liquefaction mitigation techniques requires an improved understanding of the development and consequences of liquefaction. Centrifuge experiments were performed to study the dominant mechanisms of seismically induced settlement of buildings with rigid mat foundations on thin deposits of liquefiable sand. The relative importance of key settlement mechanisms was evaluated by using mitigation techniques to minimize some of their respective contributions. The relative importance of settlement mechanisms was shown to depend on the characteristics of the earthquake motion, liquefiable soil, and building. The initiation, rate, and amount of liquefaction-induced building settlement depended greatly on the rate of ground shaking. Engineering design procedures should incorporate this important feature of earthquake shaking, which may be represented by the time rate of Arias intensity (i.e., the shaking intensity rate). In these experiments, installation of an independent, in-ground, perimetrical, stiff structural wall minimized deviatoric soil deformations under the building and reduced total building settlements by approximately 50%. Use of a flexible impermeable barrier that inhibited horizontal water flow without preventing shear deformation also reduced permanent building settlements but less significantly. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p918_s1?isAuthorized=no [article] Centrifuge testing to evaluate and mitigate liquefaction-induced building settlement mechanisms [texte imprimé] / Shideh Dashti, Auteur ; Bray, Jonathan D., Auteur ; Juan M. Pestana, Auteur . - 2010 . - pp. 918-929. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 918-929 Mots-clés : Centrifuge  Earthquakes  Liquefaction  Mitigation  Settlement  Shallow  foundation  Soil  structure  interaction Résumé : The effective application of liquefaction mitigation techniques requires an improved understanding of the development and consequences of liquefaction. Centrifuge experiments were performed to study the dominant mechanisms of seismically induced settlement of buildings with rigid mat foundations on thin deposits of liquefiable sand. The relative importance of key settlement mechanisms was evaluated by using mitigation techniques to minimize some of their respective contributions. The relative importance of settlement mechanisms was shown to depend on the characteristics of the earthquake motion, liquefiable soil, and building. The initiation, rate, and amount of liquefaction-induced building settlement depended greatly on the rate of ground shaking. Engineering design procedures should incorporate this important feature of earthquake shaking, which may be represented by the time rate of Arias intensity (i.e., the shaking intensity rate). In these experiments, installation of an independent, in-ground, perimetrical, stiff structural wall minimized deviatoric soil deformations under the building and reduced total building settlements by approximately 50%. Use of a flexible impermeable barrier that inhibited horizontal water flow without preventing shear deformation also reduced permanent building settlements but less significantly. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p918_s1?isAuthorized=no

Mechanisms of seismically induced settlement of buildings with shallow foundations on liquefiable soil / Shideh Dashti in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 1 (Janvier 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 151-164 Titre : Mechanisms of seismically induced settlement of buildings with shallow foundations on liquefiable soil Type de document : texte imprimé Auteurs : Shideh Dashti, Auteur ; Bray, Jonathan D., Auteur ; Juan M. Pestana, Auteur Article en page(s) : pp. 151-164 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Centrifuge  Earthquakes  Liquefaction  Performance-based  design  Soil-structure  interaction  Settlement Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Seismically induced settlement of buildings with shallow foundations on liquefiable soils has resulted in significant damage in recent earthquakes. Engineers still largely estimate seismic building settlement using procedures developed to calculate postliquefaction reconsolidation settlement in the free-field. A series of centrifuge experiments involving buildings situated atop a layered soil deposit have been performed to identify the mechanisms involved in liquefaction-induced building settlement. Previous studies of this problem have identified important factors including shaking intensity, the liquefiable soil's relative density and thickness, and the building's weight and width. Centrifuge test results indicate that building settlement is not proportional to the thickness of the liquefiable layer and that most of this settlement occurs during earthquake strong shaking. Building-induced shear deformations combined with localized volumetric strains during partially drained cyclic loading are the dominant mechanisms. The development of high excess pore pressures, localized drainage in response to the high transient hydraulic gradients, and earthquake-induced ratcheting of the buildings into the softened soil are important effects that should be captured in design procedures that estimate liquefaction-induced building settlement. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...] [article] Mechanisms of seismically induced settlement of buildings with shallow foundations on liquefiable soil [texte imprimé] / Shideh Dashti, Auteur ; Bray, Jonathan D., Auteur ; Juan M. Pestana, Auteur . - pp. 151-164. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 1 (Janvier 2010) . - pp. 151-164 Mots-clés : Centrifuge  Earthquakes  Liquefaction  Performance-based  design  Soil-structure  interaction  Settlement Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Seismically induced settlement of buildings with shallow foundations on liquefiable soils has resulted in significant damage in recent earthquakes. Engineers still largely estimate seismic building settlement using procedures developed to calculate postliquefaction reconsolidation settlement in the free-field. A series of centrifuge experiments involving buildings situated atop a layered soil deposit have been performed to identify the mechanisms involved in liquefaction-induced building settlement. Previous studies of this problem have identified important factors including shaking intensity, the liquefiable soil's relative density and thickness, and the building's weight and width. Centrifuge test results indicate that building settlement is not proportional to the thickness of the liquefiable layer and that most of this settlement occurs during earthquake strong shaking. Building-induced shear deformations combined with localized volumetric strains during partially drained cyclic loading are the dominant mechanisms. The development of high excess pore pressures, localized drainage in response to the high transient hydraulic gradients, and earthquake-induced ratcheting of the buildings into the softened soil are important effects that should be captured in design procedures that estimate liquefaction-induced building settlement. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.aip.org/vsearch/servlet/VerityServlet?KEY=JGGEFK&smode=strres [...]