Documents disponibles écrits par cet auteur

Assessment of reinforcement strains in very tall mechanically stabilized earth walls / Armin W. Stuedlein in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 3 (Mars 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 345-356 Titre : Assessment of reinforcement strains in very tall mechanically stabilized earth walls Type de document : texte imprimé Auteurs : Armin W. Stuedlein, Auteur ; Tony M. Allen, Auteur ; Robert D. Holtz, Auteur Année de publication : 2012 Article en page(s) : pp. 345-356 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Soil  stabilization  Retaining  walls  Performance  Instrumentation  Design  procedures Résumé : The grade raising associated with the Third Runway Project at Seattle-Tacoma International Airport included construction of tall mechanically stabilized earth (MSE) walls, including the near-vertical, two-tier, 26-m North MSE wall and the near-vertical, four-tier, 46-m tall west MSE wall. Twenty reinforcement strips at critical wall cross sections were instrumented with over 500 strain gauges to monitor strains during and following construction. The reinforcement loads inferred from observed strains are of interest because of their great height and global reinforcement stiffness, which place these walls outside the range in height and stiffness used to calibrate commonly used design methods. This paper presents the development and distribution of reinforcement strains measured during and following the construction of these walls. The reinforcement stresses calculated using the original reinforcement load design methods and design friction angle agreed with those inferred from the measured strains. The accuracy of two standard-of-practice and two alternate design methods is evaluated by comparing the reinforcement loads inferred from measured strains to those calculated using the actual friction angle of the reinforced fill material. Advantages and limitations in these design methods are identified, and recommendations for the improvement of some of these methods are provided. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i3/p345_s1?isAuthorized=no [article] Assessment of reinforcement strains in very tall mechanically stabilized earth walls [texte imprimé] / Armin W. Stuedlein, Auteur ; Tony M. Allen, Auteur ; Robert D. Holtz, Auteur . - 2012 . - pp. 345-356. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 345-356 Mots-clés : Soil  stabilization  Retaining  walls  Performance  Instrumentation  Design  procedures Résumé : The grade raising associated with the Third Runway Project at Seattle-Tacoma International Airport included construction of tall mechanically stabilized earth (MSE) walls, including the near-vertical, two-tier, 26-m North MSE wall and the near-vertical, four-tier, 46-m tall west MSE wall. Twenty reinforcement strips at critical wall cross sections were instrumented with over 500 strain gauges to monitor strains during and following construction. The reinforcement loads inferred from observed strains are of interest because of their great height and global reinforcement stiffness, which place these walls outside the range in height and stiffness used to calibrate commonly used design methods. This paper presents the development and distribution of reinforcement strains measured during and following the construction of these walls. The reinforcement stresses calculated using the original reinforcement load design methods and design friction angle agreed with those inferred from the measured strains. The accuracy of two standard-of-practice and two alternate design methods is evaluated by comparing the reinforcement loads inferred from measured strains to those calculated using the actual friction angle of the reinforced fill material. Advantages and limitations in these design methods are identified, and recommendations for the improvement of some of these methods are provided. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v138/i3/p345_s1?isAuthorized=no

LRFD calibration for steel strip reinforced soil walls / Bingquan Huang in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 8 (Août 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 8 (Août 2012) . - pp. 922–933 Titre : LRFD calibration for steel strip reinforced soil walls Type de document : texte imprimé Auteurs : Bingquan Huang, Auteur ; Richard J. Bathurst, Auteur ; Tony M. Allen, Auteur Année de publication : 2012 Article en page(s) : pp. 922–933 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Retaining  walls  Steel  reinforcement  Load  and  resistance  factor  design  Reliability  Pullout  Yield Résumé : The paper reports the results of load and resistance factor design (LRFD) calibration for pullout and yield limit states for steel strip reinforced soil walls under self-weight loading. An important feature of the calibration method is the use of bias statistics to account for prediction accuracy of the underlying deterministic models for reinforcement load, pullout capacity and yield strength of the steel strips, and random variability in input parameters. To improve the accuracy of reinforcement load predictions, small adjustments to current semiempirical American Association of State Highway and Transportation Officials (AASHTO) load design charts are proposed. Similarly, current empirical-based design charts found in AASHTO and Federal Highway Administration (FHWA) guidance documents for the estimation of the pullout resistance factor for smooth and ribbed steel strips are adjusted to improve the accuracy of pullout capacity predictions. The results of calibration lead to a load factor of 1.35 that is consistent with current practice and resistance factors that together give a consistent probability of failure of 1% for all three limit states considered. Furthermore, comparison with allowable stress design (ASD) past practice (AASHTO simplified method) shows that the operational factors of safety using a rigorous LRFD approach give the same or higher factors of safety and lower probabilities of failure. In this study, data for steel strip reinforced soil walls are used as an example to illustrate rigorous reliability theory-based LRFD calibration concepts. However, the general approach is applicable to other reinforced soil wall technologies and calibration outcomes can be updated as more data become available. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000665 [article] LRFD calibration for steel strip reinforced soil walls [texte imprimé] / Bingquan Huang, Auteur ; Richard J. Bathurst, Auteur ; Tony M. Allen, Auteur . - 2012 . - pp. 922–933. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 8 (Août 2012) . - pp. 922–933 Mots-clés : Retaining  walls  Steel  reinforcement  Load  and  resistance  factor  design  Reliability  Pullout  Yield Résumé : The paper reports the results of load and resistance factor design (LRFD) calibration for pullout and yield limit states for steel strip reinforced soil walls under self-weight loading. An important feature of the calibration method is the use of bias statistics to account for prediction accuracy of the underlying deterministic models for reinforcement load, pullout capacity and yield strength of the steel strips, and random variability in input parameters. To improve the accuracy of reinforcement load predictions, small adjustments to current semiempirical American Association of State Highway and Transportation Officials (AASHTO) load design charts are proposed. Similarly, current empirical-based design charts found in AASHTO and Federal Highway Administration (FHWA) guidance documents for the estimation of the pullout resistance factor for smooth and ribbed steel strips are adjusted to improve the accuracy of pullout capacity predictions. The results of calibration lead to a load factor of 1.35 that is consistent with current practice and resistance factors that together give a consistent probability of failure of 1% for all three limit states considered. Furthermore, comparison with allowable stress design (ASD) past practice (AASHTO simplified method) shows that the operational factors of safety using a rigorous LRFD approach give the same or higher factors of safety and lower probabilities of failure. In this study, data for steel strip reinforced soil walls are used as an example to illustrate rigorous reliability theory-based LRFD calibration concepts. However, the general approach is applicable to other reinforced soil wall technologies and calibration outcomes can be updated as more data become available. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000665

Predicted loads in steel reinforced soil walls using the AASHTO simplified method / Richard J. Bathurst in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N°2 (Février 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N°2 (Février 2009) . - pp. 177–184 Titre : Predicted loads in steel reinforced soil walls using the AASHTO simplified method Type de document : texte imprimé Auteurs : Richard J. Bathurst, Auteur ; Axel Nernheim, Auteur ; Tony M. Allen, Auteur Année de publication : 2009 Article en page(s) : pp. 177–184 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil  stabilization  Walls  Steel  Static  loads  Statistics  Data  analysis Résumé : The paper investigates the accuracy of the AASHTO simplified method by using load measurements reported in a large database of full-scale instrumented walls for bar mat, welded wire, and steel strip soil reinforced walls. The accuracy of the AASHTO simplified method is quantified by computing the mean and coefficient of variation of the ratio (bias) of measured loads under operational conditions to predicted loads. The paper shows that for steel strip walls, the AASHTO simplified method is reasonably accurate for granular backfill soils with friction angles less than 45°. For bar mat walls, the method is demonstrated to be slightly conservative. The simplified method underpredicts reinforcement loads at shallow overburden depths for steel strip walls with backfill friction angles greater than 45° due to compaction-related effects. It is concluded that these compaction-induced loads near the wall top do not contribute to internal instability due to pullout. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A2%2817 [...] [article] Predicted loads in steel reinforced soil walls using the AASHTO simplified method [texte imprimé] / Richard J. Bathurst, Auteur ; Axel Nernheim, Auteur ; Tony M. Allen, Auteur . - 2009 . - pp. 177–184. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N°2 (Février 2009) . - pp. 177–184 Mots-clés : Soil  stabilization  Walls  Steel  Static  loads  Statistics  Data  analysis Résumé : The paper investigates the accuracy of the AASHTO simplified method by using load measurements reported in a large database of full-scale instrumented walls for bar mat, welded wire, and steel strip soil reinforced walls. The accuracy of the AASHTO simplified method is quantified by computing the mean and coefficient of variation of the ratio (bias) of measured loads under operational conditions to predicted loads. The paper shows that for steel strip walls, the AASHTO simplified method is reasonably accurate for granular backfill soils with friction angles less than 45°. For bar mat walls, the method is demonstrated to be slightly conservative. The simplified method underpredicts reinforcement loads at shallow overburden depths for steel strip walls with backfill friction angles greater than 45° due to compaction-related effects. It is concluded that these compaction-induced loads near the wall top do not contribute to internal instability due to pullout. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A2%2817 [...]