Documents disponibles écrits par cet auteur

Estimating subgrade reaction modulus for transversely isotropic rock medium / Robert Y. Liang in Journal of geotechnical and geoenvironmental engineering, Vol. 136 N° 8 (Août 2010) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 8 (Août 2010) . - pp. 1077-1086 Titre : Estimating subgrade reaction modulus for transversely isotropic rock medium Type de document : texte imprimé Auteurs : Robert Y. Liang, Auteur ; Ehab S. Shatnawi, Auteur Année de publication : 2010 Article en page(s) : pp. 1077-1086 Note générale : Géotechnique Langues : Anglais (eng) Mots-clés : Subgrade  reaction  modulus  Transverse  isotropy  P-y  curve  Finite  element  Rock  mass  Rock  socketed  drilled  shaft  Lateral  deflection Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Most of the rock medium possesses intrinsic grain orientation or preferred bedding and joint directions, thus requiring the use of at least transverse isotropy to describe its elastic behavior. This paper presents a series of charts, based on extensive finite element parametric studies along with nonlinear regression analysis of FE simulation results, for estimating the subgrade reaction modulus (or initial tangent to the p-y curve) using five elastic constants of a transversely isotropic rock mass. The proper characterization of subgrade reaction modulus is critical for accurate prediction of the elastic lateral deflection of a rock socketed drilled shaft under the applied lateral loads. The sensitivity of the response of a laterally loaded drilled shaft to the degree of anisotropy and orientation of the plane of anisotropy (bedding plane direction of the rock medium) was demonstrated in this paper for an actual lateral load testing case in Ohio. It is highly recommended to use five elastic constants to estimate subgrade reaction modulus of rock medium exhibiting high degree of cross anisotropy. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i8/p1077_s1?isAuthorized=no [article] Estimating subgrade reaction modulus for transversely isotropic rock medium [texte imprimé] / Robert Y. Liang, Auteur ; Ehab S. Shatnawi, Auteur . - 2010 . - pp. 1077-1086. Géotechnique Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 136 N° 8 (Août 2010) . - pp. 1077-1086 Mots-clés : Subgrade  reaction  modulus  Transverse  isotropy  P-y  curve  Finite  element  Rock  mass  Rock  socketed  drilled  shaft  Lateral  deflection Index. décimale : 624.1 Infrastructures.Ouvrages en terre. Fondations. Tunnels Résumé : Most of the rock medium possesses intrinsic grain orientation or preferred bedding and joint directions, thus requiring the use of at least transverse isotropy to describe its elastic behavior. This paper presents a series of charts, based on extensive finite element parametric studies along with nonlinear regression analysis of FE simulation results, for estimating the subgrade reaction modulus (or initial tangent to the p-y curve) using five elastic constants of a transversely isotropic rock mass. The proper characterization of subgrade reaction modulus is critical for accurate prediction of the elastic lateral deflection of a rock socketed drilled shaft under the applied lateral loads. The sensitivity of the response of a laterally loaded drilled shaft to the degree of anisotropy and orientation of the plane of anisotropy (bedding plane direction of the rock medium) was demonstrated in this paper for an actual lateral load testing case in Ohio. It is highly recommended to use five elastic constants to estimate subgrade reaction modulus of rock medium exhibiting high degree of cross anisotropy. DEWEY : 624.1 ISSN : 1090-0241 En ligne : http://ascelibrary.org/gto/resource/1/jggefk/v136/i8/p1077_s1?isAuthorized=no

Nonuniform corrosion - induced stresses in steel - reinforced concrete / Ning Xia in Journal of engineering mechanics, Vol. 138 N° 4 (Avril 2012) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 138 N° 4 (Avril 2012) . - pp.338-346 Titre : Nonuniform corrosion - induced stresses in steel - reinforced concrete Type de document : texte imprimé Auteurs : Ning Xia, Auteur ; Qingwen Ren, Auteur ; Robert Y. Liang, Auteur Année de publication : 2012 Article en page(s) : pp.338-346 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Corrosion  Concrete  Expansion  Stress  Degradation Résumé : Understanding of cracking behavior of cover concrete is important for assessment of the remaining service life of corrosion-affected concrete structures. Predicting initiation of concrete cracking is commonly based on the evolution of stresses caused by the volume expansion of corrosion products on reinforcing bars. This paper presents an analytical method that is capable of providing the solution to two-dimensional (2D) elastic stress field caused by nonuniform volume expansion around the corroding reinforcing bars. The developed method features the formulation of a displacement model, which is applied as a boundary condition to simulate the effect of nonuniform corrosion on the deformation of the surrounding concrete. A closed-form solution to the stress field is obtained using the complex variable method of Muskhelishvili. Validation of the solution is supported by a comparison with finite-element-based simulation results. The solution reveals the evolution of stresses surrounding two typical locations of steel bars in reinforced-concrete components: the middle bar and the corner bar. Further, a comparison of stresses induced by nonuniform corrosion and uniform corrosion indicates that nonuniform corrosion pattern could lead to earlier initiation of crack given the same amount of corrosion weight loss. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000337 [article] Nonuniform corrosion - induced stresses in steel - reinforced concrete [texte imprimé] / Ning Xia, Auteur ; Qingwen Ren, Auteur ; Robert Y. Liang, Auteur . - 2012 . - pp.338-346. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 138 N° 4 (Avril 2012) . - pp.338-346 Mots-clés : Corrosion  Concrete  Expansion  Stress  Degradation Résumé : Understanding of cracking behavior of cover concrete is important for assessment of the remaining service life of corrosion-affected concrete structures. Predicting initiation of concrete cracking is commonly based on the evolution of stresses caused by the volume expansion of corrosion products on reinforcing bars. This paper presents an analytical method that is capable of providing the solution to two-dimensional (2D) elastic stress field caused by nonuniform volume expansion around the corroding reinforcing bars. The developed method features the formulation of a displacement model, which is applied as a boundary condition to simulate the effect of nonuniform corrosion on the deformation of the surrounding concrete. A closed-form solution to the stress field is obtained using the complex variable method of Muskhelishvili. Validation of the solution is supported by a comparison with finite-element-based simulation results. The solution reveals the evolution of stresses surrounding two typical locations of steel bars in reinforced-concrete components: the middle bar and the corner bar. Further, a comparison of stresses induced by nonuniform corrosion and uniform corrosion indicates that nonuniform corrosion pattern could lead to earlier initiation of crack given the same amount of corrosion weight loss. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000337