Documents disponibles écrits par cet auteur

Load resistance factor design of axially loaded pile based on load test results / Sumanta Haldar in Journal of geotechnical and geoenvironmental engineering, Vol. 134 n°8 (Août 2008) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1106–1117 Titre : Load resistance factor design of axially loaded pile based on load test results Type de document : texte imprimé Auteurs : Sumanta Haldar, Auteur ; G. L. Sivakumar Babu, Auteur Année de publication : 2008 Article en page(s) : pp. 1106–1117 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Load  and  resistance  factor  design  Monte  Carlo  method  Pile  load  tests  Reliability  Ultimate  loads  Piles  Axial  loads  Load  tests Résumé : The present study proposes a procedure to determine partial factors in reliability based design format for pile foundations, considering bias as well as uncertainty in the parameters that represent soil-pile interaction. These issues are addressed using pile load-settlement test data from case studies obtained from the literature. The pile ultimate capacities are evaluated considering three different failure criteria. The uncertainties in the pile-soil interface parameters as well as pile ultimate capacity are quantified in Monte Carlo framework from the measured data by utilizing the closed form “ t-z ” method. Considering dead load to live load ratios as calibration points, the target reliability index is calculated based on existing code safety-checking format. The optimal partial factors are determined such that the difference between reliability index based on limit state equations expressed in terms of partial factors and target reliability index is minimum. Finally, it is observed that optimal partial factors enable rational choice of allowable load on pile foundation. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...] [article] Load resistance factor design of axially loaded pile based on load test results [texte imprimé] / Sumanta Haldar, Auteur ; G. L. Sivakumar Babu, Auteur . - 2008 . - pp. 1106–1117. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 134 n°8 (Août 2008) . - pp. 1106–1117 Mots-clés : Load  and  resistance  factor  design  Monte  Carlo  method  Pile  load  tests  Reliability  Ultimate  loads  Piles  Axial  loads  Load  tests Résumé : The present study proposes a procedure to determine partial factors in reliability based design format for pile foundations, considering bias as well as uncertainty in the parameters that represent soil-pile interaction. These issues are addressed using pile load-settlement test data from case studies obtained from the literature. The pile ultimate capacities are evaluated considering three different failure criteria. The uncertainties in the pile-soil interface parameters as well as pile ultimate capacity are quantified in Monte Carlo framework from the measured data by utilizing the closed form “ t-z ” method. Considering dead load to live load ratios as calibration points, the target reliability index is calculated based on existing code safety-checking format. The optimal partial factors are determined such that the difference between reliability index based on limit state equations expressed in terms of partial factors and target reliability index is minimum. Finally, it is observed that optimal partial factors enable rational choice of allowable load on pile foundation. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282008%29134%3A8%2811 [...]

Optimum design for external seismic stability of geosynthetic reinforced soil walls / B. Munwar Basha in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 6 (Juin 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 6 (Juin 2010) . - pp. 797-812 Titre : Optimum design for external seismic stability of geosynthetic reinforced soil walls : reliability based approach Type de document : texte imprimé Auteurs : B. Munwar Basha, Auteur ; G. L. Sivakumar Babu, Auteur Année de publication : 2010 Article en page(s) : pp. 797-812 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Stability  Limit  equilibrium  Seismic  design  Geosynthetics  Reliability  System  reliability Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper, an analytical study considering the effect of uncertainties in the seismic analysis of geosynthetic-reinforced soil (GRS) walls is presented. Using limit equilibrium method and assuming sliding wedge failure mechanism, analysis is conducted to evaluate the external stability of GRS walls when subjected to earthquake loads. Target reliability based approach is used to estimate the probability of failure in three modes of failure, viz., sliding, bearing, and eccentricity failure. The properties of reinforced backfill, retained backfill, foundation soil, and geosynthetic reinforcement are treated as random variables. In addition, the uncertainties associated with horizontal seismic acceleration and surcharge load acting on the wall are considered. The optimum length of reinforcement needed to maintain the stability against three modes of failure by targeting various component and system reliability indices is obtained. Studies have also been made to study the influence of various parameters on the seismic stability in three failure modes. The results are compared with those given by first-order second moment method and Monte Carlo simulation methods. In the illustrative example, external stability of the two walls, Gould and Valencia walls, subjected to Northridge earthquake is reexamined. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i6/p797_s1?isAuthorized=no [article] Optimum design for external seismic stability of geosynthetic reinforced soil walls : reliability based approach [texte imprimé] / B. Munwar Basha, Auteur ; G. L. Sivakumar Babu, Auteur . - 2010 . - pp. 797-812. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 6 (Juin 2010) . - pp. 797-812 Mots-clés : Stability  Limit  equilibrium  Seismic  design  Geosynthetics  Reliability  System  reliability Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In this paper, an analytical study considering the effect of uncertainties in the seismic analysis of geosynthetic-reinforced soil (GRS) walls is presented. Using limit equilibrium method and assuming sliding wedge failure mechanism, analysis is conducted to evaluate the external stability of GRS walls when subjected to earthquake loads. Target reliability based approach is used to estimate the probability of failure in three modes of failure, viz., sliding, bearing, and eccentricity failure. The properties of reinforced backfill, retained backfill, foundation soil, and geosynthetic reinforcement are treated as random variables. In addition, the uncertainties associated with horizontal seismic acceleration and surcharge load acting on the wall are considered. The optimum length of reinforcement needed to maintain the stability against three modes of failure by targeting various component and system reliability indices is obtained. Studies have also been made to study the influence of various parameters on the seismic stability in three failure modes. The results are compared with those given by first-order second moment method and Monte Carlo simulation methods. In the illustrative example, external stability of the two walls, Gould and Valencia walls, subjected to Northridge earthquake is reexamined. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i6/p797_s1?isAuthorized=no

Reliability analysis of earth dams / G. L. Sivakumar Babu in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 7 (Juillet 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 995-1009 Titre : Reliability analysis of earth dams Type de document : texte imprimé Auteurs : G. L. Sivakumar Babu, Auteur ; Amit Srivastava, Auteur Année de publication : 2010 Article en page(s) : pp. 995-1009 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Reliability  Earthen  dams  Seismic  effects  Dam  safety Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In the present study, results of reliability analyses of four selected rehabilitated earth dam sections, i.e., Chang, Tapar, Rudramata, and Kaswati, under pseudostatic loading conditions, are presented. Using the response surface methodology, in combination with first order reliability method and numerical analysis, the reliability index (β) values are obtained and results are interpreted in conjunction with conventional factor of safety values. The influence of considering variability in the input soil shear strength parameters, horizontal seismic coefficient (αh), and location of reservoir full level on the stability assessment of the earth dam sections is discussed in the probabilistic framework. A comparison of results with those obtained from other method of reliability analysis, viz., Monte Carlo simulations combined with limit equilibrium approach, provided a basis for discussing the stability of earth dams in probabilistic terms, and the results of the analysis suggest that the considered earth dam sections are reliable and are expected to perform satisfactorily. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p995_s1?isAuthorized=no [article] Reliability analysis of earth dams [texte imprimé] / G. L. Sivakumar Babu, Auteur ; Amit Srivastava, Auteur . - 2010 . - pp. 995-1009. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 7 (Juillet 2010) . - pp. 995-1009 Mots-clés : Reliability  Earthen  dams  Seismic  effects  Dam  safety Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : In the present study, results of reliability analyses of four selected rehabilitated earth dam sections, i.e., Chang, Tapar, Rudramata, and Kaswati, under pseudostatic loading conditions, are presented. Using the response surface methodology, in combination with first order reliability method and numerical analysis, the reliability index (β) values are obtained and results are interpreted in conjunction with conventional factor of safety values. The influence of considering variability in the input soil shear strength parameters, horizontal seismic coefficient (αh), and location of reservoir full level on the stability assessment of the earth dam sections is discussed in the probabilistic framework. A comparison of results with those obtained from other method of reliability analysis, viz., Monte Carlo simulations combined with limit equilibrium approach, provided a basis for discussing the stability of earth dams in probabilistic terms, and the results of the analysis suggest that the considered earth dam sections are reliable and are expected to perform satisfactorily. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i7/p995_s1?isAuthorized=no