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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4. Conclusion This research focused on evaluating the seismic performance 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 study employed a detailed methodology involving the development of a numerical model, pushover analyses, retrofitting design, and non-linear static analysis. The comprehensive examination of the existing school building's seismic behaviour revealed deficiencies, necessitating the implementation of a seismic strengthening intervention. A 2D parallel steel exoskeleton system was chosen for its advantages in improving overall stiffness and resistance to lateral actions without disrupting daily activities. The design process followed a systematic approach, considering the seismic performance evaluation, material selection, exoskeleton configuration, cross-section types, and dimensions determination. The proposed intervention involved the installation of 24 shear walls symmetrically arranged along the exterior perimeter, enhancing the transfer of horizontal forces from the existing structure. Nonlinear static analyses were performed to assess the post-intervention seismic performance. The results indicated a significant increase in stiffness and lateral resistance, providing enhanced safety against seismic actions. The safety ratios between the strengthened building's performance and the demanded performance exceeded unity for all considered limit states, confirming the structure's safety and effectiveness of the retrofitting technique. References ASCE, 2018. Seismic Evaluation and Retrofit of Existing Buildings. ASCE/SEI 41 - 17 2018, American Society of Civil Engineers. CEN, 2004. EN 1998 - 1:2005. Eurocode 8: Design of structures for earthquake resistance - Part 1: General rules, seismic actions and rules for buildings, Comité Européen de Normalisation, Brussels. CEN, 2005. EN 1998 - 3:2005. Eurocode 8: Design of structures for earthquake resistance - Part 3: Assessment and retrofitting of buildings, Comité Européen de Normalisation, Brussels. CEN, 2019. EN 10025 - 1:2019. Eurocode: Hot rolled products of structural steels - Part 1: General technical delivery conditions, Comité Européen de Normalisation, Brussels. Computers and Structures Inc., 2022. SAP2000 Integrated Software for Structural Analysis and Design. Berkeley, California 2022. CS.LL.PP., 2018. Aggiornamento delle norme tecniche per le costruzioni. Rome, Italy: Gazzetta Ufficiale della Repubblica Italiana 42 [in Italian]. CS.LL.PP., 2019. Circolare n.7 21/01/2019 - Istruzioni per l'applicazione dell'«Aggiornamento delle "Norme tecniche per le costruzioni"» [in Italian]. Di Lorenzo, G., Colacurcio, E., Di Filippo, A., Formisano, A., Massimilla, A., Landolfo, R., 2020. State - of - the - art on steel exoskeletons for seismic retrofit of existing RC buildings. Ing Sismica 37(1), 33–50. Di Lorenzo, G., Tartaglia, R., Prota, A., Landolfo, R., 2023. Design procedure for orthogonal steel exoskeleton structures for seismic strengthening. Eng Struct 275, 115252. Fajfar, P., 1999. Capacity spectrum method based on inelastic demand spectra. Earthq Eng Struct Dyn 28(9), 979–93. Fajfar, P., 2000. A nonlinear analysis method for performance - based seismic design. Earthquake Spectra 16(3), 573 - 592. Marini, A., Belleri, A., Passoni, C., Feroldi, F., Giuriani, E., 2022. In - plane capacity of existing post - WWII beam - and - clay block floor systems. Bulletin of Earthquake Engineering 20, 1655–1683. O.P.C.M. 3274, 2004. Primi elementi in materia di criteri generali per la classificazione sismica del territorio nazionale e di normative tecniche per le costruzioni in zona sismica. [in Italian]. Prota, A., Tartaglia, R., Di Lorenzo, G., Landolfo, R., 2024. Seismic strengthening of isolat - ed RC framed structures through orthogonal steel exoskeleton: Bidirectional non - linear analyses. Engineering Structures 302, 117496. Simoes da Silva, L., Rebelo, C., Nethercot, D., Marques, L., Simoes, R., Vila Real, P.M.M., 2009. Statistical evaluation of the lateral–torsional buckling resistance of steel I - beams, Part 2: Variability of Steel properties. J. Constr. Steel Res. 65(4), 832–849. Vidic, T., Fajfar, P., Fischinger. M., 1994. Consistent inelastic design spectra: strength and displacement. Earthq Eng Struct Dyn 23(5), 507–521