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Importance of lower-bound capacities in the design of deep foundations / Shadi S. Najjar in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 7 (Juillet 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 7 (Juillet 2009) . - pp. 890–900 Titre : Importance of lower-bound capacities in the design of deep foundations Type de document : texte imprimé Auteurs : Shadi S. Najjar, Auteur ; Robert B. Gilbert, Auteur Année de publication : 2009 Article en page(s) : pp. 890–900 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Deep  foundations  Foundation  design  Load  and  resistance  factor  design  Reliability Résumé : There is generally a physical limit to the smallest possible capacity for a deep foundation. However, a lower bound on the capacity has rarely been accounted for in performing reliability analyses and developing reliability-based design codes. The objectives of this paper are to investigate the effect of having a lower-bound capacity on the reliability of a geotechnical engineering system and to propose a load and resistance factor design (LRFD) checking format that includes information on the lower-bound capacity in design. It is concluded that a lower-bound capacity can cause a significant increase in the calculated reliability for a geotechnical design even if it is an uncertain estimate. Two alternative LRFD formats that incorporate lower-bound capacities and that would not require substantive changes to existing codes are proposed. Real-world examples dealing with the design of onshore and offshore foundations indicate that the incorporation of a lower-bound capacity into design is expected to provide a more realistic quantification of reliability for decision-making purposes and therefore a more rational and efficient basis for design. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000044 [article] Importance of lower-bound capacities in the design of deep foundations [texte imprimé] / Shadi S. Najjar, Auteur ; Robert B. Gilbert, Auteur . - 2009 . - pp. 890–900. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 7 (Juillet 2009) . - pp. 890–900 Mots-clés : Deep  foundations  Foundation  design  Load  and  resistance  factor  design  Reliability Résumé : There is generally a physical limit to the smallest possible capacity for a deep foundation. However, a lower bound on the capacity has rarely been accounted for in performing reliability analyses and developing reliability-based design codes. The objectives of this paper are to investigate the effect of having a lower-bound capacity on the reliability of a geotechnical engineering system and to propose a load and resistance factor design (LRFD) checking format that includes information on the lower-bound capacity in design. It is concluded that a lower-bound capacity can cause a significant increase in the calculated reliability for a geotechnical design even if it is an uncertain estimate. Two alternative LRFD formats that incorporate lower-bound capacities and that would not require substantive changes to existing codes are proposed. Real-world examples dealing with the design of onshore and offshore foundations indicate that the incorporation of a lower-bound capacity into design is expected to provide a more realistic quantification of reliability for decision-making purposes and therefore a more rational and efficient basis for design. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000044