Documents disponibles écrits par cet auteur

Long-term monitoring of strain in instrumented piles / Bengt H. Fellenius 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. 1583–1595 Titre : Long-term monitoring of strain in instrumented piles Type de document : texte imprimé Auteurs : Bengt H. Fellenius, Auteur ; Sung-Ryul Kim, Auteur ; Sung-Gyo Chung, Auteur Année de publication : 2009 Article en page(s) : pp. 1583–1595 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : InstrumentationPilesGroutingStrainMeasurementsSwellingMonitoring Résumé : The development of strain in two 31 and 56 m long instrumented postdriving grouted cylinder piles at a site west of Busan, South Korea, were monitored during 200 days after construction, whereupon a static loading test was performed. Initial strain measurements showed unexpected elongation of the pile, probably due to swelling from absorption of water but as the soil reconsolidated, the elongation changed into shortening, probably due to imposed residual load in the pile. The resulting compression of the pile eventually offset the swelling of the pile. To investigate the cause of the strain changes more closely and enhance the evaluation of the field data, two short pile pieces were prepared and placed free-standing above ground in an outside laboratory. One piece was from a cylinder pile of which central void was grouted and one was made up by grouting inside a temporary casing. The monitoring showed that the short pieces appeared first to shorten and then to elongate due to the heating and cooling from the hydration process. When strains and temperature had stabilized 150 days after start of the study, both pieces were submerged to introduce swelling of the concrete. For the first 100 days after submerging, the swelling strains in both short pieces amounted to 100 με . Seven hundred days after submersion, the total swelling strains were 150 and 250 με . En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000124 [article] Long-term monitoring of strain in instrumented piles [texte imprimé] / Bengt H. Fellenius, Auteur ; Sung-Ryul Kim, Auteur ; Sung-Gyo Chung, Auteur . - 2009 . - pp. 1583–1595. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 11 (Novembre 2009) . - pp. 1583–1595 Mots-clés : InstrumentationPilesGroutingStrainMeasurementsSwellingMonitoring Résumé : The development of strain in two 31 and 56 m long instrumented postdriving grouted cylinder piles at a site west of Busan, South Korea, were monitored during 200 days after construction, whereupon a static loading test was performed. Initial strain measurements showed unexpected elongation of the pile, probably due to swelling from absorption of water but as the soil reconsolidated, the elongation changed into shortening, probably due to imposed residual load in the pile. The resulting compression of the pile eventually offset the swelling of the pile. To investigate the cause of the strain changes more closely and enhance the evaluation of the field data, two short pile pieces were prepared and placed free-standing above ground in an outside laboratory. One piece was from a cylinder pile of which central void was grouted and one was made up by grouting inside a temporary casing. The monitoring showed that the short pieces appeared first to shorten and then to elongate due to the heating and cooling from the hydration process. When strains and temperature had stabilized 150 days after start of the study, both pieces were submerged to introduce swelling of the concrete. For the first 100 days after submerging, the swelling strains in both short pieces amounted to 100 με . Seven hundred days after submersion, the total swelling strains were 150 and 250 με . En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000124

Pile drag load and downdrag in a liquefaction event / Bengt H. Fellenius in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°9 (Septembre 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°9 (Septembre 2008) . - pp. 1412–1416 Titre : Pile drag load and downdrag in a liquefaction event Type de document : texte imprimé Auteurs : Bengt H. Fellenius, Auteur ; Timothy C. Siegel, Auteur Année de publication : 2008 Article en page(s) : pp. 1412–1416 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Earthquakes  Liquefaction  Seismic  design  Piles  Specifications Résumé : Sandy soils may undergo compression during liquefaction. A review of published design manuals, including the 2004 AASHTO LRFD Bridge Design Specifications, indicates that some recommendations for pile design may not represent the pile response in a manner consistent with the actual axial response of the pile during liquefaction. The actual response is discussed in light of the unified pile design method and separated between liquefaction occurring above and below the static nonliquefied neutral plane location before the liquefaction event. In the former case, the effect on the pile is minor regardless of the magnitude of liquefaction-induced settlement of the surrounding soil. In the latter case, the axial compressive load in the pile increases and additional pile settlement (downdrag) will occur when the force equilibrium is reestablished through the necessary mobilization of additional toe resistance. This means that the magnitude of the downdrag is governed by the pile toe load-movement response to the downward shift of the neutral plane. While there is a reduction in shaft resistance due to the reduction in strength within the liquefied layers, this reduction will only influence the pile design length where the liquefying layer is very thick. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A9%2814 [...] [article] Pile drag load and downdrag in a liquefaction event [texte imprimé] / Bengt H. Fellenius, Auteur ; Timothy C. Siegel, Auteur . - 2008 . - pp. 1412–1416. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°9 (Septembre 2008) . - pp. 1412–1416 Mots-clés : Earthquakes  Liquefaction  Seismic  design  Piles  Specifications Résumé : Sandy soils may undergo compression during liquefaction. A review of published design manuals, including the 2004 AASHTO LRFD Bridge Design Specifications, indicates that some recommendations for pile design may not represent the pile response in a manner consistent with the actual axial response of the pile during liquefaction. The actual response is discussed in light of the unified pile design method and separated between liquefaction occurring above and below the static nonliquefied neutral plane location before the liquefaction event. In the former case, the effect on the pile is minor regardless of the magnitude of liquefaction-induced settlement of the surrounding soil. In the latter case, the axial compressive load in the pile increases and additional pile settlement (downdrag) will occur when the force equilibrium is reestablished through the necessary mobilization of additional toe resistance. This means that the magnitude of the downdrag is governed by the pile toe load-movement response to the downward shift of the neutral plane. While there is a reduction in shaft resistance due to the reduction in strength within the liquefied layers, this reduction will only influence the pile design length where the liquefying layer is very thick. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A9%2814 [...]