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Caisson foundations subjected to reverse fault rupture / M. Loli in Journal of geotechnical and geoenvironmental engineering, Vol. 137 N° 10 (Octobre 2011) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 914-925 Titre : Caisson foundations subjected to reverse fault rupture : centrifuge testing and numerical analysis Type de document : texte imprimé Auteurs : M. Loli, Auteur ; I. Anastasopoulos, Auteur ; M. F. Bransby, Auteur Année de publication : 2012 Article en page(s) : pp. 914-925 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Thrust  fault  Finite  elements  3D  analysis  Caisson  foundations  Centrifuge  modeling  Soil-caisson-rupture  interaction  Tectonic  deformation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Recent large-magnitude (M>7) earthquakes have caused numerous failures induced by surface faulting, demonstrating the need to account for tectonic deformation in seismic design. Thanks to their usually high rigidity, embedded (e.g., caisson) foundations may divert the fault rupture and lead to favorable performance, whereas surface or piled foundations may fail. We present a series of centrifuge model tests to investigate the response of caisson foundations embedded in a cohesionless soil stratum, the base of which is subjected to reverse faulting. We elucidate the interplay between the propagating fault rupture and the caisson, focusing on the role of the location of the outcropping rupture relative to the caisson. The rigid-body of the caisson causes diversion and/or bifurcation of the shear localization, which is forced to develop preferentially around the edges of the caisson. The observed failure pattern and the consequent caisson response depend strongly on the exact caisson position relative to the fault. We employed three-dimensional (3D) finite-element (FE) modeling and validated it by comparing to centrifuge test results. The numerical method captures the general interaction mechanisms, showing satisfactory (if not always perfect) agreement with experiments. We then employ the validated numerical method in a parametric investigation, providing further insight into the different possible modes of foundation response. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i10/p914_s1?isAuthorized=no [article] Caisson foundations subjected to reverse fault rupture : centrifuge testing and numerical analysis [texte imprimé] / M. Loli, Auteur ; I. Anastasopoulos, Auteur ; M. F. Bransby, Auteur . - 2012 . - pp. 914-925. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 137 N° 10 (Octobre 2011) . - pp. 914-925 Mots-clés : Thrust  fault  Finite  elements  3D  analysis  Caisson  foundations  Centrifuge  modeling  Soil-caisson-rupture  interaction  Tectonic  deformation Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Recent large-magnitude (M>7) earthquakes have caused numerous failures induced by surface faulting, demonstrating the need to account for tectonic deformation in seismic design. Thanks to their usually high rigidity, embedded (e.g., caisson) foundations may divert the fault rupture and lead to favorable performance, whereas surface or piled foundations may fail. We present a series of centrifuge model tests to investigate the response of caisson foundations embedded in a cohesionless soil stratum, the base of which is subjected to reverse faulting. We elucidate the interplay between the propagating fault rupture and the caisson, focusing on the role of the location of the outcropping rupture relative to the caisson. The rigid-body of the caisson causes diversion and/or bifurcation of the shear localization, which is forced to develop preferentially around the edges of the caisson. The observed failure pattern and the consequent caisson response depend strongly on the exact caisson position relative to the fault. We employed three-dimensional (3D) finite-element (FE) modeling and validated it by comparing to centrifuge test results. The numerical method captures the general interaction mechanisms, showing satisfactory (if not always perfect) agreement with experiments. We then employ the validated numerical method in a parametric investigation, providing further insight into the different possible modes of foundation response. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v137/i10/p914_s1?isAuthorized=no

Soil-foundation-structure interaction with mobilization of bearing capacity / V. Drosos in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 11 (Novembre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 11 (Novembre 2012) . - pp. 1369–1386 Titre : Soil-foundation-structure interaction with mobilization of bearing capacity : Experimental study on sand Type de document : texte imprimé Auteurs : V. Drosos, Auteur ; T. Georgarakos, Auteur ; M. Loli, Auteur Année de publication : 2013 Article en page(s) : pp. 1369–1386 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Shallow  foundation  Nonlinear  behavior  Bridge  pier  Shaking  table  testing  Experiment  Seismic  response  Slow-cyclic  pushover Résumé : Recent studies have highlighted the beneficial role of foundation uplifting and the potential effectiveness of guiding the plastic hinge into the foundation soil by allowing full mobilization of bearing capacity during strong seismic shaking. With the inertia loading transmitted onto the superstructure being limited by the capacity of the foundation, this concept may provide an alternative method of in-ground seismic isolation: the so-called rocking isolation. Attempting to unravel the effectiveness of this alternative design method, this paper experimentally investigates the nonlinear response of a surface foundation on sand and its effect on the seismic performance of an idealized slender single-degree-of-freedom structure. Using a bridge pier as an illustrative prototype, three foundation design alternatives are considered, representing three levels of design conservatism. Their performance is investigated through static (monotonic and slow-cyclic pushover) loading, and reduced-scale shaking table testing. Rocking isolation may provide a valid alternative for the seismic protection of structures, providing encouraging evidence in favor of the innovative idea of moving foundation design toward a less conservative, even unconventional, treatment. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000705 [article] Soil-foundation-structure interaction with mobilization of bearing capacity : Experimental study on sand [texte imprimé] / V. Drosos, Auteur ; T. Georgarakos, Auteur ; M. Loli, Auteur . - 2013 . - pp. 1369–1386. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 11 (Novembre 2012) . - pp. 1369–1386 Mots-clés : Shallow  foundation  Nonlinear  behavior  Bridge  pier  Shaking  table  testing  Experiment  Seismic  response  Slow-cyclic  pushover Résumé : Recent studies have highlighted the beneficial role of foundation uplifting and the potential effectiveness of guiding the plastic hinge into the foundation soil by allowing full mobilization of bearing capacity during strong seismic shaking. With the inertia loading transmitted onto the superstructure being limited by the capacity of the foundation, this concept may provide an alternative method of in-ground seismic isolation: the so-called rocking isolation. Attempting to unravel the effectiveness of this alternative design method, this paper experimentally investigates the nonlinear response of a surface foundation on sand and its effect on the seismic performance of an idealized slender single-degree-of-freedom structure. Using a bridge pier as an illustrative prototype, three foundation design alternatives are considered, representing three levels of design conservatism. Their performance is investigated through static (monotonic and slow-cyclic pushover) loading, and reduced-scale shaking table testing. Rocking isolation may provide a valid alternative for the seismic protection of structures, providing encouraging evidence in favor of the innovative idea of moving foundation design toward a less conservative, even unconventional, treatment. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000705