Documents disponibles écrits par cet auteur

Finite Element Sensitivity Analysis of Steel-Concrete Composite Beams with Deformable Shear Connection / Zona, A. in Journal of engineering mechanics, Vol.131, N°11 (Novembre 2005) 

Public ISBD [article]  in Journal of engineering mechanics > Vol.131, N°11 (Novembre 2005) . - 1126-1139 p. Titre : Finite Element Sensitivity Analysis of Steel-Concrete Composite Beams with Deformable Shear Connection Titre original : Analyse Finie de Sensibilité d'Elément des Faisceaux Composés Concrets en Acier avec le Raccordement de Déformable Cisaillement Type de document : texte imprimé Auteurs : Zona, A., Auteur ; Barbato, M., Auteur ; Conte, J. P. Article en page(s) : 1126-1139 p. Note générale : Génie Mécanique, Génie civil Langues : Anglais (eng) Mots-clés : Finite  element  method  Composite  beams  Steel  Concrete  Connections  Sensitivity  analysis  Méthode  d'élément  fini  Faisceaux  composés  Acier  Raccordements  Analyse  de  sensibilité Index. décimale : 621.34/624 Résumé : The Behavior of steel concrete composite beams is strongly influenced by the type of shear connection between the steel beam and the concrete slab. For accurate analytical predictions, the structural model must account for the interlayer slip brtween these two comonents. In numerous engineering applications (e.g., in the fields of structural optimization, structural reliability analysis, and finite element model updating), accurate response sensitivity calculations are needed as much as the corresponding response simulation results. This Paper focuses on a procedure for response sensitivity analysis of steel concrete composite structures using displacement based locking free frame elements including deformable shear connection with fiber discretization of the cross section. Realistic cyclic uniaxial constitutive laws are adopted for the steel and concrete materials as well as for the shear connection. The Finite element response sensitivity analysis is performed according to the direct differentiation method. The Concrete and shear connection material models as well as the static condensation procedure at the element level are extended for response sensitivity computations. Two steel concrete composite structures for which experimental test results are available in the literature are used as realistic testbeds for response and response sensitivity analysis. These benchmark structures consists of a nonsymmetric, two span continuous beam subjected to monotonic loading and a frame subassemblage under cyclic loading. The New analytical derivations for response sensitivity calculations and their computer implementation are validated through forward finite difference analysis based on the two benchmark examples considered. Selected sensitivity analysis results are shown for validation purposes and for quantifying the effect and relativeimportance of the various material parameters in regards to the nonlinear monotonic and cyclic response of the testbed structures. Le comportement des faisceaux composés concrets en acier est fortement influencé par le type de raccordement de cisaillement entre le faisceau en acier et la dalle en de béton. Pour des prévisions analytiques précises, le modèle structural doit expliquer la glissade de couche intercalaire brtween ces deux comonents. Dans de nombreuses applications de technologie (par exemple, dans les domaines de l'optimisation structurale, de l'analyse structurale de fiabilité, et de la mise à jour modèle d'élément fini), des calculs précis de sensibilité de réponse sont nécessaires autant que les résultats correspondants de simulation de réponse. Cet article se concentre sur un procédé pour l'analyse de sensibilité de réponse des structures composées en béton en acier en utilisant le déplacement basé fermant les éléments libres d'armature comprenant le raccordement deformable de cisaillement avec la discrétisation de fibre de la coupe. Des lois constitutives uniaxiales cycliques réalistes sont adoptées pour l'acier et les matériaux concrets aussi bien que pour le raccordement de cisaillement. L'analyse finie de sensibilité de réponse d'élément est exécutée selon la méthode directe de différentiation. Les modèles matériels de raccordement de béton et de cisaillement aussi bien que le procédé statique de condensation au niveau d'élément sont prolongés pour des calculs de sensibilité de réponse. Deux structures composées en béton en acier pour lesquelles les résultats d'essai expérimentaux sont disponibles dans la littérature sont employées en tant que bancs d'essai réalistes pour l'analyse de réponse et de sensibilité de réponse. Ces structures de repère se compose d'un nonsymmetric, d'un faisceau continu de deux envergures soumis au chargement monotonique et d'un subassemblage d'armature sous le chargement cyclique. Les nouvelles dérivations analytiques pour des calculs de sensibilité de réponse et leur exécution d'ordinateur sont validées par l'analyse finie vers l'avant de différence basée sur les deux exemples de repère considérés. Des résultats choisis d'analyse de sensibilité sont montrés pour la validation et pour mesurer l'effet et le relativeimportance des divers paramètres matériels dans le respect à la réponse monotonique et cyclique non-linéaire des structures de banc d'essai. En ligne : azona@ucsd.edu, mbarbato@ucsd.edu, jpconte@ucsd.edu [article] Finite Element Sensitivity Analysis of Steel-Concrete Composite Beams with Deformable Shear Connection = Analyse Finie de Sensibilité d'Elément des Faisceaux Composés Concrets en Acier avec le Raccordement de Déformable Cisaillement [texte imprimé] / Zona, A., Auteur ; Barbato, M., Auteur ; Conte, J. P. . - 1126-1139 p. Génie Mécanique, Génie civil Langues : Anglais (eng) in Journal of engineering mechanics > Vol.131, N°11 (Novembre 2005) . - 1126-1139 p. Mots-clés : Finite  element  method  Composite  beams  Steel  Concrete  Connections  Sensitivity  analysis  Méthode  d'élément  fini  Faisceaux  composés  Acier  Raccordements  Analyse  de  sensibilité Index. décimale : 621.34/624 Résumé : The Behavior of steel concrete composite beams is strongly influenced by the type of shear connection between the steel beam and the concrete slab. For accurate analytical predictions, the structural model must account for the interlayer slip brtween these two comonents. In numerous engineering applications (e.g., in the fields of structural optimization, structural reliability analysis, and finite element model updating), accurate response sensitivity calculations are needed as much as the corresponding response simulation results. This Paper focuses on a procedure for response sensitivity analysis of steel concrete composite structures using displacement based locking free frame elements including deformable shear connection with fiber discretization of the cross section. Realistic cyclic uniaxial constitutive laws are adopted for the steel and concrete materials as well as for the shear connection. The Finite element response sensitivity analysis is performed according to the direct differentiation method. The Concrete and shear connection material models as well as the static condensation procedure at the element level are extended for response sensitivity computations. Two steel concrete composite structures for which experimental test results are available in the literature are used as realistic testbeds for response and response sensitivity analysis. These benchmark structures consists of a nonsymmetric, two span continuous beam subjected to monotonic loading and a frame subassemblage under cyclic loading. The New analytical derivations for response sensitivity calculations and their computer implementation are validated through forward finite difference analysis based on the two benchmark examples considered. Selected sensitivity analysis results are shown for validation purposes and for quantifying the effect and relativeimportance of the various material parameters in regards to the nonlinear monotonic and cyclic response of the testbed structures. Le comportement des faisceaux composés concrets en acier est fortement influencé par le type de raccordement de cisaillement entre le faisceau en acier et la dalle en de béton. Pour des prévisions analytiques précises, le modèle structural doit expliquer la glissade de couche intercalaire brtween ces deux comonents. Dans de nombreuses applications de technologie (par exemple, dans les domaines de l'optimisation structurale, de l'analyse structurale de fiabilité, et de la mise à jour modèle d'élément fini), des calculs précis de sensibilité de réponse sont nécessaires autant que les résultats correspondants de simulation de réponse. Cet article se concentre sur un procédé pour l'analyse de sensibilité de réponse des structures composées en béton en acier en utilisant le déplacement basé fermant les éléments libres d'armature comprenant le raccordement deformable de cisaillement avec la discrétisation de fibre de la coupe. Des lois constitutives uniaxiales cycliques réalistes sont adoptées pour l'acier et les matériaux concrets aussi bien que pour le raccordement de cisaillement. L'analyse finie de sensibilité de réponse d'élément est exécutée selon la méthode directe de différentiation. Les modèles matériels de raccordement de béton et de cisaillement aussi bien que le procédé statique de condensation au niveau d'élément sont prolongés pour des calculs de sensibilité de réponse. Deux structures composées en béton en acier pour lesquelles les résultats d'essai expérimentaux sont disponibles dans la littérature sont employées en tant que bancs d'essai réalistes pour l'analyse de réponse et de sensibilité de réponse. Ces structures de repère se compose d'un nonsymmetric, d'un faisceau continu de deux envergures soumis au chargement monotonique et d'un subassemblage d'armature sous le chargement cyclique. Les nouvelles dérivations analytiques pour des calculs de sensibilité de réponse et leur exécution d'ordinateur sont validées par l'analyse finie vers l'avant de différence basée sur les deux exemples de repère considérés. Des résultats choisis d'analyse de sensibilité sont montrés pour la validation et pour mesurer l'effet et le relativeimportance des divers paramètres matériels dans le respect à la réponse monotonique et cyclique non-linéaire des structures de banc d'essai. En ligne : azona@ucsd.edu, mbarbato@ucsd.edu, jpconte@ucsd.edu

Influence of model parameter uncertainty on seismic transverse response and vulnerability of steel–concrete composite bridges with dual load path / E. Tubaldi in Journal of structural engineering, Vol. 138 N° 3 (Mars 2012) 

Public ISBD [article]  in Journal of structural engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 363-374 Titre : Influence of model parameter uncertainty on seismic transverse response and vulnerability of steel–concrete composite bridges with dual load path Type de document : texte imprimé Auteurs : E. Tubaldi, Auteur ; Barbato, M., Auteur ; A. Dall’Asta, Auteur Année de publication : 2012 Article en page(s) : pp. 363-374 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Steel-concrete  composite  structures  Bridges  Nonlinear  finite  element  method  Seismic  behavior  Incremental  dynamic  analysis  Performance-based  earthquake  engineering Résumé : This paper uses a fully probabilistic approach to investigate the seismic response of multispan continuous bridges with dissipative piers and a steel–concrete composite (SCC) deck, the motion of which is transversally restrained at the abutments. This bridge typology is characterized by complex dual load path behavior in the transverse direction, with multiple failure modes involving both the deck and the piers. Proper assessment of the seismic vulnerability of these structural systems must rigorously take into account all pertinent sources of uncertainty, including uncertainties in both the seismic input (record-to-record variability) and the properties defining the structural model (model parameters). Model parameter uncertainty affects not only the structural capacity, but also the seismic response of a structural system. However, most of the procedures for seismic vulnerability assessment focus on the variability of the response resulting solely from seismic input uncertainty. These procedures either neglect model parameter uncertainty effects or incorporate these effects only in a simplified way. A computationally expensive but rigorous procedure is introduced in this work to include the effects of model parameter uncertainty on the seismic response and vulnerability assessment of SCC bridges with dual load path. Monte Carlo simulation with Latin hypercube sampling, in conjunction with probabilistic moment–curvature analysis, is used to build probabilistic finite-element models of the bridges under study. Extended incremental dynamic analysis is used to propagate all pertinent sources of uncertainty to the seismic demand. The proposed procedure is then applied to the assessment of three benchmark bridges exhibiting different seismic behavior and dominant failure modes. Comparison of the response variability induced by seismic input uncertainty and the response variability induced by model parameter uncertainty highlights the importance of accounting for the latter when evaluating the safety of the typology of bridges considered in this study. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i3/p363_s1?isAuthorized=no [article] Influence of model parameter uncertainty on seismic transverse response and vulnerability of steel–concrete composite bridges with dual load path [texte imprimé] / E. Tubaldi, Auteur ; Barbato, M., Auteur ; A. Dall’Asta, Auteur . - 2012 . - pp. 363-374. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 3 (Mars 2012) . - pp. 363-374 Mots-clés : Steel-concrete  composite  structures  Bridges  Nonlinear  finite  element  method  Seismic  behavior  Incremental  dynamic  analysis  Performance-based  earthquake  engineering Résumé : This paper uses a fully probabilistic approach to investigate the seismic response of multispan continuous bridges with dissipative piers and a steel–concrete composite (SCC) deck, the motion of which is transversally restrained at the abutments. This bridge typology is characterized by complex dual load path behavior in the transverse direction, with multiple failure modes involving both the deck and the piers. Proper assessment of the seismic vulnerability of these structural systems must rigorously take into account all pertinent sources of uncertainty, including uncertainties in both the seismic input (record-to-record variability) and the properties defining the structural model (model parameters). Model parameter uncertainty affects not only the structural capacity, but also the seismic response of a structural system. However, most of the procedures for seismic vulnerability assessment focus on the variability of the response resulting solely from seismic input uncertainty. These procedures either neglect model parameter uncertainty effects or incorporate these effects only in a simplified way. A computationally expensive but rigorous procedure is introduced in this work to include the effects of model parameter uncertainty on the seismic response and vulnerability assessment of SCC bridges with dual load path. Monte Carlo simulation with Latin hypercube sampling, in conjunction with probabilistic moment–curvature analysis, is used to build probabilistic finite-element models of the bridges under study. Extended incremental dynamic analysis is used to propagate all pertinent sources of uncertainty to the seismic demand. The proposed procedure is then applied to the assessment of three benchmark bridges exhibiting different seismic behavior and dominant failure modes. Comparison of the response variability induced by seismic input uncertainty and the response variability induced by model parameter uncertainty highlights the importance of accounting for the latter when evaluating the safety of the typology of bridges considered in this study. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i3/p363_s1?isAuthorized=no

Probabilistic push-over analysis of structural and soil-structure systems / Barbato, M. in Journal of structural engineering, Vol. 136 N° 11 (Novembre 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 11 (Novembre 2010) . - pp. 1330-1341 Titre : Probabilistic push-over analysis of structural and soil-structure systems Type de document : texte imprimé Auteurs : Barbato, M., Auteur ; Q. Gu, Auteur ; Conte, J. P., Auteur Année de publication : 2011 Article en page(s) : pp. 1330-1341 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Nonlinear  finite-element  model  Finite-element  response  sensitivity  Random  parameter  First-order  second-moment  method  Engineering  demand  parameter Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, the mean-centered first-order second-moment (FOSM) method is employed to perform probabilistic push-over analysis (POA) of structural and/or soil-structure systems. Approximations of first and second statistical moments (FSSMs) of engineering demand parameters (EDPs) of structural and/or geotechnical systems with random material parameters are computed based on finite-element (FE) response and response sensitivity analysis (RSA) results. The FE RSA is performed accurately and efficiently by using the direct differentiation method (DDM) and is employed to evaluate the relative importance (RI) of the various modeling material parameters in influencing the variability of the EDPs. The proposed approximate methodology is illustrated through probabilistic POA results for nonlinear inelastic FE models of: (1) a three-story reinforced-concrete (RC) frame building and (2) a soil-foundation-structure interaction system consisting of a RC frame structure founded on layered soil. FSSMs of EDPs computed through the FOSM method are compared with the corresponding accurate estimates obtained via Monte Carlo simulation. Results obtained from “exact” (or “local”) and “averaged” (or “global”) response sensitivities are also compared. The RI of the material parameters describing the systems is studied in both the deterministic and probabilistic sense, and presented in the form of tornado diagrams. Effects of statistical correlation between material parameters are also considered and analyzed by the FOSM method. A simple approximation of the probability density function and cumulative distribution function of EDPs due to a single random parameter at a time (while all the other parameters are fixed to their mean values) is also proposed. Conclusions are drawn on both the appropriateness of using local RSA for simplified probabilistic POA and on the application limits of the FOSM method. It is observed that the FOSM method combined with the DDM provides accurate estimates of FSSMs of EDPs for low-to-moderate level of inelastic structural or system behavior and useful qualitative information on the RI ranking of material parameters on the structural or system response for high level of inelastic behavior. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i11/p1330_s1?isAuthorized=no [article] Probabilistic push-over analysis of structural and soil-structure systems [texte imprimé] / Barbato, M., Auteur ; Q. Gu, Auteur ; Conte, J. P., Auteur . - 2011 . - pp. 1330-1341. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 11 (Novembre 2010) . - pp. 1330-1341 Mots-clés : Nonlinear  finite-element  model  Finite-element  response  sensitivity  Random  parameter  First-order  second-moment  method  Engineering  demand  parameter Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, the mean-centered first-order second-moment (FOSM) method is employed to perform probabilistic push-over analysis (POA) of structural and/or soil-structure systems. Approximations of first and second statistical moments (FSSMs) of engineering demand parameters (EDPs) of structural and/or geotechnical systems with random material parameters are computed based on finite-element (FE) response and response sensitivity analysis (RSA) results. The FE RSA is performed accurately and efficiently by using the direct differentiation method (DDM) and is employed to evaluate the relative importance (RI) of the various modeling material parameters in influencing the variability of the EDPs. The proposed approximate methodology is illustrated through probabilistic POA results for nonlinear inelastic FE models of: (1) a three-story reinforced-concrete (RC) frame building and (2) a soil-foundation-structure interaction system consisting of a RC frame structure founded on layered soil. FSSMs of EDPs computed through the FOSM method are compared with the corresponding accurate estimates obtained via Monte Carlo simulation. Results obtained from “exact” (or “local”) and “averaged” (or “global”) response sensitivities are also compared. The RI of the material parameters describing the systems is studied in both the deterministic and probabilistic sense, and presented in the form of tornado diagrams. Effects of statistical correlation between material parameters are also considered and analyzed by the FOSM method. A simple approximation of the probability density function and cumulative distribution function of EDPs due to a single random parameter at a time (while all the other parameters are fixed to their mean values) is also proposed. Conclusions are drawn on both the appropriateness of using local RSA for simplified probabilistic POA and on the application limits of the FOSM method. It is observed that the FOSM method combined with the DDM provides accurate estimates of FSSMs of EDPs for low-to-moderate level of inelastic structural or system behavior and useful qualitative information on the RI ranking of material parameters on the structural or system response for high level of inelastic behavior. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i11/p1330_s1?isAuthorized=no