Documents disponibles écrits par cet auteur

Long-term lateral cyclic response of suction caisson foundations in sand / Zhu, B. in Journal of geotechnical and geoenvironmental engineering, Vol. 139 N° 1 (Janvier 2013) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 1 (Janvier 2013) . - pp. 73-83 Titre : Long-term lateral cyclic response of suction caisson foundations in sand Type de document : texte imprimé Auteurs : Zhu, B., Auteur ; B. W. Byrne, Auteur ; Houlsby, G. T., Auteur Année de publication : 2013 Article en page(s) : pp. 73-83 Note générale : geotechnique Langues : Anglais (eng) Mots-clés : suction;  caissons;  turbines;  offshore  structures;  rotation;  stiffness;  shallow  foundations;  sand  (soil  type) Résumé : Skirted gravity base foundations and suction caisson foundations are considered as viable alternatives to monopile foundations for offshore wind turbines. While recent work has focused on the monotonic moment-rotation response for shallow foundations, the cyclic response and the accumulation of rotation over the life of the turbine must also be addressed. This paper presents cyclic loading tests where approximately 10,000 cycles, with different loading characteristics, were applied to a model shallow foundation (a caisson) in loose sand. On the basis of these tests, a framework for assessing the accumulated angular rotation because of cycling was developed. The settlement and cyclic stiffness response of the caisson were also assessed. It was found, not unexpectedly, that the accumulated settlement of the caisson increased with the number of cycles and cyclic amplitude. It was also found that a cyclic loading regime intermediate between one-way and full two-way cycling produced the largest rotations. The cyclic stiffness was relatively unaffected by the number of cycles. Using an appropriate scaling technique, the proposed framework was used to predict the long-term accumulated angular rotation, for an example, the field-scale monocaisson structure. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000738 [article] Long-term lateral cyclic response of suction caisson foundations in sand [texte imprimé] / Zhu, B., Auteur ; B. W. Byrne, Auteur ; Houlsby, G. T., Auteur . - 2013 . - pp. 73-83. geotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 139 N° 1 (Janvier 2013) . - pp. 73-83 Mots-clés : suction;  caissons;  turbines;  offshore  structures;  rotation;  stiffness;  shallow  foundations;  sand  (soil  type) Résumé : Skirted gravity base foundations and suction caisson foundations are considered as viable alternatives to monopile foundations for offshore wind turbines. While recent work has focused on the monotonic moment-rotation response for shallow foundations, the cyclic response and the accumulation of rotation over the life of the turbine must also be addressed. This paper presents cyclic loading tests where approximately 10,000 cycles, with different loading characteristics, were applied to a model shallow foundation (a caisson) in loose sand. On the basis of these tests, a framework for assessing the accumulated angular rotation because of cycling was developed. The settlement and cyclic stiffness response of the caisson were also assessed. It was found, not unexpectedly, that the accumulated settlement of the caisson increased with the number of cycles and cyclic amplitude. It was also found that a cyclic loading regime intermediate between one-way and full two-way cycling produced the largest rotations. The cyclic stiffness was relatively unaffected by the number of cycles. Using an appropriate scaling technique, the proposed framework was used to predict the long-term accumulated angular rotation, for an example, the field-scale monocaisson structure. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000738

Response of stiff piles in sand to long-term cyclic lateral loading / C. Leblanc in Géotechnique, Vol. 60 N° 2 (Fevrier 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 2 (Fevrier 2010) . - pp. 79–90 Titre : Response of stiff piles in sand to long-term cyclic lateral loading Type de document : texte imprimé Auteurs : C. Leblanc, Auteur ; Houlsby, G. T., Auteur ; B. W. Byrne, Auteur Année de publication : 2011 Article en page(s) : pp. 79–90 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Stiffness  Piles  Settlement  Repeated  loading  Laboratory  tests  Sands Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The driven monopile is currently the preferred foundation type for most offshore wind farms. While the static capacity of the monopile is important, a safe design must also address issues of accumulated rotation and changes in stiffness after long-term cyclic loading. Design guidance on this issue is limited. To address this, a series of laboratory tests were conducted where a stiff pile in drained sand was subjected to between 8000 and 60 000 cycles of combined moment and horizontal loading. A typical design for an offshore wind turbine monopile was used as a basis for the study, to ensure that pile dimensions and loading ranges were realistic. A complete non-dimensional framework for stiff piles in sand is presented, and applied to interpret the test results. The accumulated rotation was found to be dependent on relative density, and was strongly affected by the characteristics of the applied cyclic load. Particular loading characteristics were found to cause a significant increase in the accumulated rotation. The pile stiffness increased with number of cycles, which contrasts with the current methodology where static load–displacement curves are degraded to account for cyclic loading. Methods are presented to predict the change in stiffness and the accumulated rotation of a stiff pile due to long-term cyclic loading. The use of the methods developed is demonstrated for a typical full-scale monopile. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.7.00196 [article] Response of stiff piles in sand to long-term cyclic lateral loading [texte imprimé] / C. Leblanc, Auteur ; Houlsby, G. T., Auteur ; B. W. Byrne, Auteur . - 2011 . - pp. 79–90. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 2 (Fevrier 2010) . - pp. 79–90 Mots-clés : Stiffness  Piles  Settlement  Repeated  loading  Laboratory  tests  Sands Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The driven monopile is currently the preferred foundation type for most offshore wind farms. While the static capacity of the monopile is important, a safe design must also address issues of accumulated rotation and changes in stiffness after long-term cyclic loading. Design guidance on this issue is limited. To address this, a series of laboratory tests were conducted where a stiff pile in drained sand was subjected to between 8000 and 60 000 cycles of combined moment and horizontal loading. A typical design for an offshore wind turbine monopile was used as a basis for the study, to ensure that pile dimensions and loading ranges were realistic. A complete non-dimensional framework for stiff piles in sand is presented, and applied to interpret the test results. The accumulated rotation was found to be dependent on relative density, and was strongly affected by the characteristics of the applied cyclic load. Particular loading characteristics were found to cause a significant increase in the accumulated rotation. The pile stiffness increased with number of cycles, which contrasts with the current methodology where static load–displacement curves are degraded to account for cyclic loading. Methods are presented to predict the change in stiffness and the accumulated rotation of a stiff pile due to long-term cyclic loading. The use of the methods developed is demonstrated for a typical full-scale monopile. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.7.00196

Response of stiff piles to random two-way lateral loading / C. Leblanc in Géotechnique, Vol. 60 N° 9 (Septembre 2010) 

Public ISBD [article]  in Géotechnique > Vol. 60 N° 9 (Septembre 2010) . - pp. 715–721 Titre : Response of stiff piles to random two-way lateral loading Type de document : texte imprimé Auteurs : C. Leblanc, Auteur ; B. W. Byrne, Auteur ; Houlsby, G. T., Auteur Année de publication : 2011 Article en page(s) : pp. 715–721 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Settlement  Sands  Deformation  Repeated  loading  Piles  Laboratory  tests Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A model for predicting the accumulated rotation of stiff piles under random two-way loading is presented. The model is based on a strain superposition rule similar to Miner's rule and uses rainflow-counting to decompose a random time-series of varying loads into a set of simple load reversals. The method is consistent with the work of LeBlanc et al. (2010) and is supported by 1 g laboratory tests. An example is given for an offshore wind turbine indicating that accumulated pile rotation during the life of the turbine is dominated by the worst expected load. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.09.t.011 [article] Response of stiff piles to random two-way lateral loading [texte imprimé] / C. Leblanc, Auteur ; B. W. Byrne, Auteur ; Houlsby, G. T., Auteur . - 2011 . - pp. 715–721. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 60 N° 9 (Septembre 2010) . - pp. 715–721 Mots-clés : Settlement  Sands  Deformation  Repeated  loading  Piles  Laboratory  tests Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A model for predicting the accumulated rotation of stiff piles under random two-way loading is presented. The model is based on a strain superposition rule similar to Miner's rule and uses rainflow-counting to decompose a random time-series of varying loads into a set of simple load reversals. The method is consistent with the work of LeBlanc et al. (2010) and is supported by 1 g laboratory tests. An example is given for an offshore wind turbine indicating that accumulated pile rotation during the life of the turbine is dominated by the worst expected load. DEWEY : 624.15 ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.09.t.011