Simple homogenized model for the nonlinear analysis of FRP-strengthened masonry structures. I / Gabriele Milani in Journal of engineering mechanics, Vol. 139 N° 1 (Janvier 2013)  

Public ISBD [article]  inJournal of engineering mechanics > Vol. 139 N° 1 (Janvier 2013) . - pp.59–76 Titre : Simple homogenized model for the nonlinear analysis of FRP-strengthened masonry structures. I : Theory Type de document : texte imprimé Auteurs : Gabriele Milani, Auteur ; Paulo B. Lourenco, Auteur Année de publication : 2013 Article en page(s) : pp.59–76 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Masonry Simplified homogenization Nonlinear model SQP approach 3D structural analysis Résumé : A suitable and simple two-step model able to predict the nonlinear response of fiber-reinforced polymer (FRP)-strengthened three-dimensional masonry structures is presented. In the first step, nonstrengthened masonry is substituted by a macroscopically equivalent homogeneous material through a kinematic model based on finite elements and working on a heterogeneous assemblage of blocks. Nonlinearity is concentrated exclusively on joints reduced to interfaces exhibiting a frictional behavior with limited tensile and compressive strength with softening. The homogenized stress-strain behavior evaluated at the mesoscale is then implemented at a structural level in a finite-element nonlinear code, relying on an assemblage of rigid infinitely resistant six-noded wedge elements and nonlinear interfaces, exhibiting deterioration of the mechanical properties. The FRP-reinforcing strips are modeled through rigid triangles and nonlinear interfaces between adjoining triangles. Delamination from the support is accounted for by modeling the FRP-masonry bond by means of nonlinear softening triangular interfaces. Italian code formulas are used to evaluate peak interface tangential strength and postpeak behavior. In this first part, the theoretical basis of the model and the nonlinear stress-strain behavior at a cell level are discussed. Structural examples will be analyzed in the accompanying paper devoted to the structural scale. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000457 [article] Simple homogenized model for the nonlinear analysis of FRP-strengthened masonry structures. I : Theory [texte imprimé] / Gabriele Milani, Auteur ; Paulo B. Lourenco, Auteur . - 2013 . - pp.59–76. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 139 N° 1 (Janvier 2013) . - pp.59–76 Mots-clés : Masonry Simplified homogenization Nonlinear model SQP approach 3D structural analysis Résumé : A suitable and simple two-step model able to predict the nonlinear response of fiber-reinforced polymer (FRP)-strengthened three-dimensional masonry structures is presented. In the first step, nonstrengthened masonry is substituted by a macroscopically equivalent homogeneous material through a kinematic model based on finite elements and working on a heterogeneous assemblage of blocks. Nonlinearity is concentrated exclusively on joints reduced to interfaces exhibiting a frictional behavior with limited tensile and compressive strength with softening. The homogenized stress-strain behavior evaluated at the mesoscale is then implemented at a structural level in a finite-element nonlinear code, relying on an assemblage of rigid infinitely resistant six-noded wedge elements and nonlinear interfaces, exhibiting deterioration of the mechanical properties. The FRP-reinforcing strips are modeled through rigid triangles and nonlinear interfaces between adjoining triangles. Delamination from the support is accounted for by modeling the FRP-masonry bond by means of nonlinear softening triangular interfaces. Italian code formulas are used to evaluate peak interface tangential strength and postpeak behavior. In this first part, the theoretical basis of the model and the nonlinear stress-strain behavior at a cell level are discussed. Structural examples will be analyzed in the accompanying paper devoted to the structural scale. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000457

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Simple homogenized model for the nonlinear analysis of FRP-strengthened masonry structures. II / Gabriele Milani in Journal of engineering mechanics, Vol. 139 N° 1 (Janvier 2013)  

Public ISBD [article]  inJournal of engineering mechanics > Vol. 139 N° 1 (Janvier 2013) . - pp.77–93. Titre : Simple homogenized model for the nonlinear analysis of FRP-strengthened masonry structures. II : Structural applications Type de document : texte imprimé Auteurs : Gabriele Milani, Auteur ; Paulo B. Lourenco, Auteur Année de publication : 2013 Article en page(s) : pp.77–93. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Masonry FRP strengthening Nonlinear behavior In- and out-of-plane loads 3D structural analysis Curved shells Résumé : The homogenized masonry nonlinear stress-strain curves obtained through the simple micromechanical model developed in the first part of the paper are here used for the analysis of strengthened masonry walls under various loading conditions. In particular, a deep beam and a shear wall strengthened with fiber-reinforced polymer (FRP) strips are analyzed for masonry loaded in-plane. Additionally, single and double curvature masonry structures strengthened in various ways, namely a circular arch with buttresses and a ribbed cross vault, are considered. For all the examples presented, both the nonstrengthened and FRP–strengthened cases are discussed. Additional nonlinear finite-element analyses are performed, modeling masonry through an equivalent macroscopic material with softening to assess the present model predictions. Detailed comparisons between the experimental data, where available, and numerical results are also presented. The examples show the efficiency of the homogenized technique with respect to (1) accuracy of the results; (2) low number of finite elements required; and (3) independence of the mesh at a structural level from the actual texture of masonry. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000479 [article] Simple homogenized model for the nonlinear analysis of FRP-strengthened masonry structures. II : Structural applications [texte imprimé] / Gabriele Milani, Auteur ; Paulo B. Lourenco, Auteur . - 2013 . - pp.77–93. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 139 N° 1 (Janvier 2013) . - pp.77–93. Mots-clés : Masonry FRP strengthening Nonlinear behavior In- and out-of-plane loads 3D structural analysis Curved shells Résumé : The homogenized masonry nonlinear stress-strain curves obtained through the simple micromechanical model developed in the first part of the paper are here used for the analysis of strengthened masonry walls under various loading conditions. In particular, a deep beam and a shear wall strengthened with fiber-reinforced polymer (FRP) strips are analyzed for masonry loaded in-plane. Additionally, single and double curvature masonry structures strengthened in various ways, namely a circular arch with buttresses and a ribbed cross vault, are considered. For all the examples presented, both the nonstrengthened and FRP–strengthened cases are discussed. Additional nonlinear finite-element analyses are performed, modeling masonry through an equivalent macroscopic material with softening to assess the present model predictions. Detailed comparisons between the experimental data, where available, and numerical results are also presented. The examples show the efficiency of the homogenized technique with respect to (1) accuracy of the results; (2) low number of finite elements required; and (3) independence of the mesh at a structural level from the actual texture of masonry. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000479

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Validation of Analytical Multiparameter Homogenization Models for Out-of-Plane Loaded Masonry Walls by Means of the Finite Element Method / Cecchi, Antonella in Journal of engineering mechanics, Vol.131, N° 2 (Fevrier 2005)  

Public ISBD [article]  inJournal of engineering mechanics > Vol.131, N° 2 (Fevrier 2005) . - 185-198 p. Titre : Validation of Analytical Multiparameter Homogenization Models for Out-of-Plane Loaded Masonry Walls by Means of the Finite Element Method Titre original : Validation des Modèles Analytiques d'Homogénéisation de Multiparameter pour les Murs de Maçonnerie Chargés par Avion au Moyen de la Méthode d'Elément Fini Type de document : texte imprimé Auteurs : Cecchi, Antonella, Auteur ; Tralli Antonio ; Gabriele Milani, Auteur Année de publication : 2005 Article en page(s) : 185-198 p. Note générale : Génie Civil, Génie Mécanique Langues : Anglais (eng) Mots-clés : Elastic analysis Constitutive relations Orthotropism Flexural strength Finite element method Anisotropic plates Walls Masonry Analyse élastique Relations constitutives Force flexible Méthode d'élément fini Tôles anisotropes Murs Maçonnerie Ouvrage en pier Index. décimale : 621.34/624 Résumé : The Linear elastic analysis of in-plane and out-of-plane loaded masory walls is still significant under service loads and is required by codes of practice, therefore the knowledge of the homogenized mechanical properties of masonry is of relevant interest. The Aim of this paper is to discuss the problem of the out-of-plane loaded masonry walls in detail and to assess the accuracy and reliability of different homogenization approaches presented in the technical literature, with particular interest in recent explicit formulas obtained through an asymptotic model (as reported by Cecchi and Sab in 2002). Several meaningful comparisons are presented for different types of new and historical masonry structures currently employed in Italy. The Validation of the analytical models is carried out by means of a three-dimensional (3D)finite-element (FE) out-of-plane homogenization. A Final structural comparison among analytical models, FE out-of-plane homogenization, and a computationally expensive heterogeneous 3D FE model is discussed for a simply supported square panel laterally loaded. L'analyse élastique linéaire de l'dans-avion et des murs de maçonnerie chargés paravion est encore les charges de dessous significatives de service et est exigée par des recueils d'instructions, donc la connaissance des propriétés mécaniques homogénéisées de la maçonnerie est d'intérêt approprié. Le but de cet article est discuter le problème des murs de maçonnerie chargés paravion en détail et d'évaluer l'exactitude et la fiabilité de différentes approches d'homogénéisation présentées dans la littérature technique, avec l'intérêt particulier pour des formules explicites récentes obtenues par un modèle asymptotique (comme rapporté par Cecchi et Sab en 2002). Plusieurs comparaisons signicatives sont présentées pour différents types de nouvelles et historiques structures de maçonnerie actuellement utilisées en Italie. La validation des modèles analytiques est effectuée au moyen d'un tridimensionnel (homogénéisation d'dehors-de-avion 3D)finite-element (Fe). Une comparaison structurale finale l'homogénéisation analytique parmi modèles, d'dehors-de-avion de Fe, et un modèle hétérogène informatique cher de Fe 3D est discutée pour un panneau carré simplement soutenu latéralement chargé. En ligne : cecchi@iuav.it, gmilani@ing.unife.it, atralli@ing.unife.it [article] Validation of Analytical Multiparameter Homogenization Models for Out-of-Plane Loaded Masonry Walls by Means of the Finite Element Method = Validation des Modèles Analytiques d'Homogénéisation de Multiparameter pour les Murs de Maçonnerie Chargés par Avion au Moyen de la Méthode d'Elément Fini [texte imprimé] / Cecchi, Antonella, Auteur ; Tralli Antonio ; Gabriele Milani, Auteur . - 2005 . - 185-198 p. Génie Civil, Génie Mécanique Langues : Anglais (eng) in Journal of engineering mechanics > Vol.131, N° 2 (Fevrier 2005) . - 185-198 p. Mots-clés : Elastic analysis Constitutive relations Orthotropism Flexural strength Finite element method Anisotropic plates Walls Masonry Analyse élastique Relations constitutives Force flexible Méthode d'élément fini Tôles anisotropes Murs Maçonnerie Ouvrage en pier Index. décimale : 621.34/624 Résumé : The Linear elastic analysis of in-plane and out-of-plane loaded masory walls is still significant under service loads and is required by codes of practice, therefore the knowledge of the homogenized mechanical properties of masonry is of relevant interest. The Aim of this paper is to discuss the problem of the out-of-plane loaded masonry walls in detail and to assess the accuracy and reliability of different homogenization approaches presented in the technical literature, with particular interest in recent explicit formulas obtained through an asymptotic model (as reported by Cecchi and Sab in 2002). Several meaningful comparisons are presented for different types of new and historical masonry structures currently employed in Italy. The Validation of the analytical models is carried out by means of a three-dimensional (3D)finite-element (FE) out-of-plane homogenization. A Final structural comparison among analytical models, FE out-of-plane homogenization, and a computationally expensive heterogeneous 3D FE model is discussed for a simply supported square panel laterally loaded. L'analyse élastique linéaire de l'dans-avion et des murs de maçonnerie chargés paravion est encore les charges de dessous significatives de service et est exigée par des recueils d'instructions, donc la connaissance des propriétés mécaniques homogénéisées de la maçonnerie est d'intérêt approprié. Le but de cet article est discuter le problème des murs de maçonnerie chargés paravion en détail et d'évaluer l'exactitude et la fiabilité de différentes approches d'homogénéisation présentées dans la littérature technique, avec l'intérêt particulier pour des formules explicites récentes obtenues par un modèle asymptotique (comme rapporté par Cecchi et Sab en 2002). Plusieurs comparaisons signicatives sont présentées pour différents types de nouvelles et historiques structures de maçonnerie actuellement utilisées en Italie. La validation des modèles analytiques est effectuée au moyen d'un tridimensionnel (homogénéisation d'dehors-de-avion 3D)finite-element (Fe). Une comparaison structurale finale l'homogénéisation analytique parmi modèles, d'dehors-de-avion de Fe, et un modèle hétérogène informatique cher de Fe 3D est discutée pour un panneau carré simplement soutenu latéralement chargé. En ligne : cecchi@iuav.it, gmilani@ing.unife.it, atralli@ing.unife.it

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