Documents disponibles écrits par cet auteur

A centrifuge study on the effect of embedment on the drained response of shallow foundations under combined loading / L. Govoni in Géotechnique, Vol. 61 N° 12 (Décembre 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 12 (Décembre 2011) . - pp. 1055–1068 Titre : A centrifuge study on the effect of embedment on the drained response of shallow foundations under combined loading Type de document : texte imprimé Auteurs : L. Govoni, Auteur ; S. Gourvenec, Auteur ; G. Gottardi, Auteur Année de publication : 2012 Article en page(s) : pp. 1055–1068 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Bearing  capacity  Footings/foundations  Centrifuge  modelling  Plasticity  Settlement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Drum centrifuge tests with surface and buried circular footings on medium dense silica sand subjected to planar combined loading are reported. The experimental work specifically addresses the effect of the footing embedment within a work-hardening plasticity approach, which to date has been used predominantly for interpretation of the behaviour of small-scale models of surface foundations. Vertical loading and swipe tests were carried out, and results are compared with existing data from similar studies on small-scale 1g foundation models. The overall trend of the centrifuge results confirms the general framework, suggesting that a work-hardening plasticity approach in terms of force-resultant modelling for the soil–footing system (the so-called ‘macro-element') applies under properly scaled stress conditions. The data also indicate that the traditional assumption of a yield surface, isotropically expanding with increasing vertical penetration is not suitable for an embedded foundation. An enhancement of the existing yield surface formulation enables generalisation of the existing work-hardening models from surface to embedded footings. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.7.00109 [article] A centrifuge study on the effect of embedment on the drained response of shallow foundations under combined loading [texte imprimé] / L. Govoni, Auteur ; S. Gourvenec, Auteur ; G. Gottardi, Auteur . - 2012 . - pp. 1055–1068. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 12 (Décembre 2011) . - pp. 1055–1068 Mots-clés : Bearing  capacity  Footings/foundations  Centrifuge  modelling  Plasticity  Settlement Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Drum centrifuge tests with surface and buried circular footings on medium dense silica sand subjected to planar combined loading are reported. The experimental work specifically addresses the effect of the footing embedment within a work-hardening plasticity approach, which to date has been used predominantly for interpretation of the behaviour of small-scale models of surface foundations. Vertical loading and swipe tests were carried out, and results are compared with existing data from similar studies on small-scale 1g foundation models. The overall trend of the centrifuge results confirms the general framework, suggesting that a work-hardening plasticity approach in terms of force-resultant modelling for the soil–footing system (the so-called ‘macro-element') applies under properly scaled stress conditions. The data also indicate that the traditional assumption of a yield surface, isotropically expanding with increasing vertical penetration is not suitable for an embedded foundation. An enhancement of the existing yield surface formulation enables generalisation of the existing work-hardening models from surface to embedded footings. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.7.00109

Stability and strength analysis of leaning towers / M. Marchi in Géotechnique, Vol. 61 N° 12 (Décembre 2011) 

Public ISBD [article]  in Géotechnique > Vol. 61 N° 12 (Décembre 2011) . - pp. 1069–1079 Titre : Stability and strength analysis of leaning towers Type de document : texte imprimé Auteurs : M. Marchi, Auteur ; R. Butterfield, Auteur ; G. Gottardi, Auteur Année de publication : 2012 Article en page(s) : pp. 1069–1079 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Plasticity  Failure  Stiffness  Soil/structure  interaction  Footings/foundations  Creep  Bearing  capacity Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Many ancient towers are afflicted by stability problems. Shallow foundations are typical components of such structures, and their behaviour strongly influences the overall safety of the tower. This paper is concerned with two major, geotechnically related, failure modes of tower foundations: (a) bearing capacity failure, due to lack of strength of the supporting soil; and (b) instability of equilibrium, due to lack of foundation stiffness. Both of these hazards are tackled in a unified way in the paper, using a strain-hardening plasticity model for shallow footings from which a non-linear rotational stiffness (moment–rotation curve) for the soil–foundation system can be derived. The stability of equilibrium analysis is augmented by the inclusion of rotational creep, which is new, and an important feature of the behaviour of real towers. The practical utility of the analysis resides in its simplicity, input parameters being derived from conventional geotechnical data. The analysis provides not only a complete framework within which both failure mechanisms can be assessed but also a prediction of which of them is eventually most likely to be critical. The methodology is demonstrated in relation to the Pisa Tower. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.054 [article] Stability and strength analysis of leaning towers [texte imprimé] / M. Marchi, Auteur ; R. Butterfield, Auteur ; G. Gottardi, Auteur . - 2012 . - pp. 1069–1079. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 61 N° 12 (Décembre 2011) . - pp. 1069–1079 Mots-clés : Plasticity  Failure  Stiffness  Soil/structure  interaction  Footings/foundations  Creep  Bearing  capacity Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Many ancient towers are afflicted by stability problems. Shallow foundations are typical components of such structures, and their behaviour strongly influences the overall safety of the tower. This paper is concerned with two major, geotechnically related, failure modes of tower foundations: (a) bearing capacity failure, due to lack of strength of the supporting soil; and (b) instability of equilibrium, due to lack of foundation stiffness. Both of these hazards are tackled in a unified way in the paper, using a strain-hardening plasticity model for shallow footings from which a non-linear rotational stiffness (moment–rotation curve) for the soil–foundation system can be derived. The stability of equilibrium analysis is augmented by the inclusion of rotational creep, which is new, and an important feature of the behaviour of real towers. The practical utility of the analysis resides in its simplicity, input parameters being derived from conventional geotechnical data. The analysis provides not only a complete framework within which both failure mechanisms can be assessed but also a prediction of which of them is eventually most likely to be critical. The methodology is demonstrated in relation to the Pisa Tower. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.9.p.054