Documents disponibles écrits par cet auteur

Method for estimating system stiffness for excavation support walls / L. Sebastian Bryson in Journal of geotechnical and geoenvironmental engineering, Vol. 138 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1104–1115. Titre : Method for estimating system stiffness for excavation support walls Type de document : texte imprimé Auteurs : L. Sebastian Bryson, Auteur ; David G. Zapata-Medina, Auteur Année de publication : 2012 Article en page(s) : pp.1104–1115. Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Excavation  Excavation  Support  System  Stiffness  Finite-element  analysis  PLAXIS  Hardening  soil  model  Dimensional  analysis Résumé : Excessive excavation-induced movements are major concerns for most underground construction projects in urban areas. These movements can lead to significant damage in adjacent structures. When average to good workmanship is employed during the installation process of the excavation support systems, the consequent ground movements are most influenced by the support system stiffness. Therefore, choosing the most appropriate stiffness for an excavation support system is crucial to minimizing excavation-related damage to adjacent buildings and utilities. This paper presents a semiempirical design methodology that facilitates the selecting of the excavation support system stiffness in such a way that limits excavation-related ground movement. As part of the proposed design methodology, a new parameter was developed called the relative stiffness ratio. This new parameter relates the strength and stiffness of the soil with the stiffness of the excavation support system and was developed from a comprehensive parametric analysis that incorporated a fully three-dimensional finite-element analysis of a generalized excavation that realistically modeled the excavation geometry, excavation support system configuration, and excavation activities. The performance of the proposed methodology was evaluated using several excavation case histories reported worldwide. The results of the evaluation show that the new relative stiffness ratio performed well in predicting the support system bending stiffness and the actual excavation-induced lateral deformations of the case history support systems. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000683 [article] Method for estimating system stiffness for excavation support walls [texte imprimé] / L. Sebastian Bryson, Auteur ; David G. Zapata-Medina, Auteur . - 2012 . - pp.1104–1115. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 138 N° 9 (Septembre 2012) . - pp.1104–1115. Mots-clés : Excavation  Excavation  Support  System  Stiffness  Finite-element  analysis  PLAXIS  Hardening  soil  model  Dimensional  analysis Résumé : Excessive excavation-induced movements are major concerns for most underground construction projects in urban areas. These movements can lead to significant damage in adjacent structures. When average to good workmanship is employed during the installation process of the excavation support systems, the consequent ground movements are most influenced by the support system stiffness. Therefore, choosing the most appropriate stiffness for an excavation support system is crucial to minimizing excavation-related damage to adjacent buildings and utilities. This paper presents a semiempirical design methodology that facilitates the selecting of the excavation support system stiffness in such a way that limits excavation-related ground movement. As part of the proposed design methodology, a new parameter was developed called the relative stiffness ratio. This new parameter relates the strength and stiffness of the soil with the stiffness of the excavation support system and was developed from a comprehensive parametric analysis that incorporated a fully three-dimensional finite-element analysis of a generalized excavation that realistically modeled the excavation geometry, excavation support system configuration, and excavation activities. The performance of the proposed methodology was evaluated using several excavation case histories reported worldwide. The results of the evaluation show that the new relative stiffness ratio performed well in predicting the support system bending stiffness and the actual excavation-induced lateral deformations of the case history support systems. ISSN : 1090-0241 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000683

Static stability formulas of a weakened timoshenko column / David G. Zapata-Medina in Journal of engineering mechanics, Vol. 136 N° 12 (Décembre 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 12 (Décembre 2010) . - pp.1528-1536 Titre : Static stability formulas of a weakened timoshenko column : effects of shear deformations Type de document : texte imprimé Auteurs : David G. Zapata-Medina, Auteur ; Luis G. Arboleda-Monsalve, Auteur ; J. Dario Aristizabal-Ochoa, Auteur Année de publication : 2011 Article en page(s) : pp.1528-1536 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Columns  Cracking  Structural  stability  Buckling  Shear  deformation. Résumé : The static stability analysis of two-dimensional Timoshenko columns weakened at an arbitrary section is derived in a classic manner. The effects of shear deformations along the column, influenced by the additional shear force induced by the applied axial load as the member deforms according to the modified shear equation proposed by Haringx, are presented and studied in detail. The proposed model also captures: (1) the influence on the buckling load capacity of the column when an arbitrary weakened section is formed at any location; (2) the tension buckling phenomenon due to the low shear stiffness of columns made of composite materials or elastomeric rubbers; and (3) the beneficial effects of an additional lateral bracing located at the weakened section to alleviate the buckling load reduction of the column. Seven classical and nonclassical cases of columns mostly used in civil and mechanical engineering are summarized in condensed formulas which allow the straightforward determination of buckling loads and shapes. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i12/p1528_s1?isAuthorized=no [article] Static stability formulas of a weakened timoshenko column : effects of shear deformations [texte imprimé] / David G. Zapata-Medina, Auteur ; Luis G. Arboleda-Monsalve, Auteur ; J. Dario Aristizabal-Ochoa, Auteur . - 2011 . - pp.1528-1536. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 12 (Décembre 2010) . - pp.1528-1536 Mots-clés : Columns  Cracking  Structural  stability  Buckling  Shear  deformation. Résumé : The static stability analysis of two-dimensional Timoshenko columns weakened at an arbitrary section is derived in a classic manner. The effects of shear deformations along the column, influenced by the additional shear force induced by the applied axial load as the member deforms according to the modified shear equation proposed by Haringx, are presented and studied in detail. The proposed model also captures: (1) the influence on the buckling load capacity of the column when an arbitrary weakened section is formed at any location; (2) the tension buckling phenomenon due to the low shear stiffness of columns made of composite materials or elastomeric rubbers; and (3) the beneficial effects of an additional lateral bracing located at the weakened section to alleviate the buckling load reduction of the column. Seven classical and nonclassical cases of columns mostly used in civil and mechanical engineering are summarized in condensed formulas which allow the straightforward determination of buckling loads and shapes. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i12/p1528_s1?isAuthorized=no