PSI - Issue 44

Christian Salvatori et al. / Procedia Structural Integrity 44 (2023) 520–527 Christian Salvatori et al./ Structural Integrity Procedia 00 (2022) 000–000

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Three modeling strategies were followed. An unconventional strategy was implemented in the first 3D model, partially calibrated through nonlinear dynamic analyses; this intended to capture both the in-plane and out-of-plane behavior of walls and to fully describe the experimental response, with the activation of local overturning mechanisms of façades orthogonal to the shaking direction. The second 3D model followed the common practice of neglecting the out-of-plane response of masonry walls. Given the low shear stiffness of floor and roof diaphragms, the third strategy involved single-wall 2D models of the façades arranged along the shaking direction. Pushover capacity curves were compared to the experimental backbone curves. Both advanced and conventional 3D models simulated well the experimental response adopting a uniform lateral force distribution. In fact, although the conventional model slightly overestimated the strength in one loading verse, it better matched the stiffness in the other one, with some differences when looking at the full building or at each longitudinal wall results. Also analyzing single-wall 2D models with the assumption of infinitely flexible diaphragms provided reasonable results, aligned with those extracted from the conventional 3D model. This work demonstrated the validity of two common modeling assumptions for the global seismic analysis of masonry buildings. Neglecting the out-of-plane wall response did not affect the accuracy of the results, provided local collapse was no reached. Single-wall 2D analysis was justified by the low stiffness of timber diaphragms. Future investigations will extend this study to nonlinear dynamic analyses and more articulated aggregate layouts. Acknowledgements This work stems from the project “Seismic assessment of natural stone masonry buildings in Basel – A research and training project”, jointly carried by the École Polytechnique Fédérale de Lausanne and the University of Pavia, which was supported by the Swiss Federal Office for the Environment and the Construction Department of the Canton Basel Stadt. The modeling activity was funded by DPC-ReLUIS (2022-2024) Work Package 10 “Modelli di capacità locali e globali per la definizione degli stati limite, definiti in funzione del metodo di analisi”. References American Society of Civil Engineers (ASCE), 2017. Seismic Evaluation and Retrofit of Existing Buildings; ASCE 41-17. American Society of Civil Engineers, Reston, VA, USA. Bracchi, S., Galasco, A., Penna, A., 2021a. A novel macroelement model for the nonlinear analysis of masonry buildings. Part 1: axial and flexural behavior. Earthquake Engineering & Structural Dynamics 50(8), 2233-2252. 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