PSI - Issue 44

Marco Gaetani d’Aragona et al. / Procedia Structural Integrity 44 (2023) 1052–1059 Author name / Structural Integrity Procedia 00 (2022) 000–000

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regions, and according to different design requirements (i.e., gravity load only, design according to obsolete seismic code provisions), in as-built configuration and accounting for possible retrofit interventions. The procedure allows the generation of the Stick model based on a few macro-parameters: age of construction, number of stories, interstory height, surface area, and in-plan shape, consistency of infills, and opening percentage at different stories. The response of structural and non-structural elements contributing to the global seismic behavior of the RC frame is properly characterized by adopting constitutive envelopes selected from available literature proposals. Despite the simplifications introduced, the proposed procedure allows accounting for typical structural deficiencies and failure modes characterizing non-conforming RC elements in existing Italian RC buildings (e.g., local brittle failures of columns or beam-column joint panel and non-seismic details and due to the interaction with the masonry infills). The potential shear failure of the column members has been incorporated by suitably modifying the original ductile envelope, while the behavior of beam-column joints is included in the modeling through the concept of Equivalent Column Moment. To derive the interstory backbones, the interaction between different RC members at the sub-assembly level is suitably composed at the story level adopting the concepts of strength hierarchy and considering failure modes at the sub-assembly level. The presence of infills is explicitly simulated both at the global level and at the local level, considering additional shear forces induced by infill-frame interaction. The procedure allows to account for typical building-level collapse modes for existing RC infilled buildings at the story level, namely side-sway and gravity load collapse. Finally, the proposed procedure is extended to account for two possible retrofit intervention: (i) Fiber Reinforced Polymer wrapping of columns and Fiber and Steel Reinforced Polymer wrapping of beam-column joints; (ii) and Reinforced Concrete jacketing of columns. Simplified procedures are proposed to design each retrofit intervention to allow the application in large-scale assessment studies. The outcome of the proposed framework is illustrated for a gravity-load designed case-study building via pushover analysis. The proposed procedure can be adopted to generate Stick models simulating the seismic performances of large building portfolios, by considering the building-by-building response. The generated models can be also used to evidence the advantages related to the application of retrofit interventions both in terms of reduction of seismic risk and reduction of future economic losses. This model can be easily adopted to generate mechanical analyzed curves for building typologies, whether in its as-built configuration or accounting for retrofit interventions, including the effects of variabilities in material properties, geometry, modeling, and due to the uncertainties in the ground motion definition. Acknowledgements This study was performed in the framework of PE 2022–2024 joint program DPC-Reluis–subproject WP4: Risk maps and seismic damage scenarios. Borzi B., Pinho R., Crowley H., 2008. Simplified pushover-based vulnerability analysis for large-scale assessment of RC buildings. Eng Struct; 30:804–820. https://doi.org/10.1016/j.engst ruct.2007.05.021 Calvi G.M., Magenes G., and Pampanin S., 2002. Relevance of beam column damage and collapse in RC frame assessment. Journal of Earthquake Engineering; 6(1):75–100. Decreto 17 gennaio 2018 (DM2018). Aggiornamento delle “Norme tecniche per le costruzioni 2018” (in Italian). Gaetani d’Aragona M., Polese M., Di Ludovico M., Prota A., 2017a. Simplified assessment of expected seismic losses for as built and retrofitted RC buildings, proceedings of COMPDYN 2017 6th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Rhodes Island, Greece, 15–17 June 2017. Gaetani d’Aragona M., Polese M., Prota A., 2017b. Influence factors for the assessment of maximum lateral seismic deformations in Italian multistory RC buildings, proceedings of COMPDYN 2017 6th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Rhodes Island, Greece, 15–17 June 2017. Gaetani d’Aragona M., Polese M., Di Ludovico M., & Prota A., 2018a. Seismic vulnerability for RC infilled frames: Simplified evaluation for as built and retrofitted building typologies. Buildings; 8(10),137. https://doi.org/10.3390/buildings8100137. References