PSI - Issue 64

Alessandro Prota et al. / Procedia Structural Integrity 64 (2024) 1041–1048 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction Italy, situated at the convergence of the Eurasian and African tectonic plates, faces significant seismic activity. Given the pivotal role schools play in society, both as places of learning and community shelters, ensuring their seismic performance is crucial for the safety and well-being of the population, especially the younger generation. The historical backdrop reveals Italy's vulnerability to destructive earthquakes, such as the 1908 Messina earthquake, the 1968 Belice Valley earthquake, and the 1980 Irpinia earthquake. Despite these events, it was only after the 2002 Molise earthquake, resulting in the tragic death of 27 children in a collapsed school building, that seismic structural codes were updated with the OPCM 3274 (2004). The country was subsequently divided into four seismic risk zones in 2003. The majority of Italy's buildings, primarily constructed before 2003, exhibit high vulnerability to seismic activity (see Fig 1). To address this, the study emphasizes the need for structural strengthening solutions, especially for strategically significant buildings. The introduction of new seismic-resistant systems, particularly external interventions, can be a reliable approach to enhancing the seismic performance and durability of strategically important structures, as observed by Di Lorenzo et al. (2020). The study's main objectives include evaluating the structural safety of a steel school building in Southern Italy and proposing retrofitting interventions, specifically 2D parallel steel exoskeletons (EXO-2D-//), to enhance its seismic performance. The methodology involves: i) developing a detailed numerical model of the existing building, ii) performing pushover analyses to assess seismic behavior, iii) designing retrofitting interventions, considering aesthetics and usability, and iv) evaluating effectiveness through non-linear static analysis. The paper is structured to provide a comprehensive account of the research. It covers the seismic behavior evaluation of the existing school building, including data from the original design report and drawings. The numerical modeling assumptions and results of the seismic assessment, highlighting deficiencies, are presented. Retrofitting interventions using 2D parallel steel exoskeletons are designed, focusing on a displacement-based step by-step procedure developed by Di Lorenzo et al. (2023). The effectiveness of the retrofitting technique is discussed through non-linear static analysis, comparing pre- and post-retrofitting performance.

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Fig. 1. (a) F. Jovine school 2022 (San Giuliano di Puglia, Italy); (b) R. Capranica school 2016 (Amatrice, Italy)

2. Existing building assessment 2.1. Description of the building

This case study is centered on evaluating the seismic performance of an existing school building situated in Avellino, Italy. The structure under investigation is a two-story edifice featuring an irregular floor plan, covering an