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International audience; This work proposes a framework for the reevaluation of the intensity based on probabilistic method and structural analysis. The method developed in this work allows for an update of the magnitude of historical earthquakes based on structural fragility functions and comparison to the damage observed in situ. The goal of this work is to assess the feasibility of the approach initially proposed by (Ryu, Kim, & Baker, 2009) to characterize fragile structures. The Bayesian updating procedure allows for accounting for uncertainty related to the structural response, ground motion and site parameters. In order to assess the vulnerability of a large set of existing buildings a global methodology has been developed in the present work. After defining class of typology, a method used to analyze the nonlinear response of old masonry structures, in the context of low to moderate seismicity, is proposed. For the Bayesian updating, a modeling strategy tailored on the non linear analysis of large scale masonry building has been developed for the study within a probabilistic frame. MOTS-CLÉS : archéoseismicité, maçonnerie, endommagement; Ce travail propose un cadre pour la réévaluation de l'intensité basée sur des méthodes probabilistes et l'analyse structurelle. La méthode développée dans ce travail permet de mettre à jour la magnitude des séismes historiques. L'objectif de ces travaux est d'évaluer la faisabilité de l'approche initialement proposée par (Ryu, Kim, & Baker, 2009) pour l'actualisation de magnitude de séismes historiques. La procédure bayésienne de mise à jour permet de tenir compte de l'incertitude liée à la réponse structurale, au mouvement du sol et aux paramètres du site. Afin d'évaluer la vulnérabilité d'un grand nombre de bâtiments existants, une méthodologie globale a été mise au point dans le travail présenté. Après avoir défini une classe de typologie, une méthode d'analyse de la réponse non linéaire des structures de maçonnerie anciennes, dans un contexte de sismicité faible à modérée, est proposée. Pour la mise à jour bayésienne, une stratégie de modélisation adaptée à l'analyse non linéaire des bâtiments de maçonnerie à grande échelle a été développée pour l'étude dans un cadre probabiliste

International audience; The embedding of anchoring systems in the retrofitting of Reinforced Concrete (RC) structures by means of Fiber Reinforced Polymers (FRP) often implies local failure modes associated to high stress concentrations. In order to account for such mechanical behaviours in standard finite element computations, an explicit representation of interfaces is required. This strategy presents, however , several limitations in terms of computational cost and mesh-related issues. On the other hand, implicit models may not be sufficiently accurate in order to reproduce the aforementioned localized phenomena. Specific finite elements for the simulation of pull-out mechanisms are here presented. The presence of interfaces is taken into account by enriching the displacement approximation by means of additional unknowns defined at the element level. Static-condensation, therefore, allows preserving the structure of the finite element procedure and limiting the computational effort.

International audience

International audience

International audience; This work aims to develop and identify a new model for reinforced concrete joint element subject to cyclic loadings. Based on experiments and 3D numerical modeling, a simplified model of RC beam-column joint is introduced (within the framework of macro-element). In a first experimental study, this joint will be tested under reverse cyclic loading applied at the beam tip to identify its behavior under this kind of loading in terms of strength, stiffness and ductility. In parallel of experiments, a finite elements model of the joint based on 3D finite elements is presented to highlight and define the nonlinear mechanisms involved in the ruin of the assembly. This step will confirm the experimentally observed phenomena: damage, friction, plasticity. Secondly, a simplified macro-element model for beam-column joint, associated to a nonlinear behavior, is introduced to reflect the response of the joint under cyclic loading loads. Model parameters will be identified from experimental results and analysis on a local scale via 3D finite element calculation. Finally, numerical analyses will be performed to validate the proposed approach in comparison with the experimental tests.