PSI - Issue 78

Giada Frappa et al. / Procedia Structural Integrity 78 (2026) 17–24

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5. Conclusions Based on the results obtained for the case-study building, the following general conclusions may be drawn and extended to buildings with similar characteristics:  Seismic retrofitting interventions using external bracing systems can be beneficial for the following reasons: - Minimizing disruption to building activities during installation, as installation is carried out externally. - Enhancing the regularity of the seismic response by reducing the eccentricity between the center of mass and the center of rigidity. - In the case of stiff braces, contributing to the reduction of lateral displacements and, consequently, internal forces in structural elements. - In the case of energy-dissipating braces, enabling the absorption of seismic energy and thereby reducing the seismic demand on structural components.  However, seismic retrofitting with external bracing systems may not be effective in enhancing the performance of structural elements that do not meet gravitational load-bearing requirements. In such cases, additional local strengthening measures may be necessary. This condition is commonly observed in precast structures, where beams are simply supported on columns and therefore do not contribute to moment-resisting action under seismic loading, but are solely responsible for carrying vertical loads. Acknowledgements The Municipality of Resia is gratefully acknowledged for providing all the documentation related to the building, necessary for its understanding and analysis, including the design drawings and the results of in-situ material testing. The research was partially funded by Italian Department of Civil Protection (within the framework of Executive Projects DPC_ReLUIS 2024 – 2026), whose support is greatly appreciated. This work was also funded by the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.5 – D.D. 1058 23/06/2022, ECS00000043), within the Interconnected Nord-Est Innovation Ecosystem (iNEST). This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them. References Commentary on NTC 2018, Ministero delle Infrastrutture e dei Trasporti. 21 gennaio 2019, n. 7 C.S.LL.PP. —Istruzioni per l’applicazione dell’«Aggiornamento delle “Norme tecniche per le costruzioni”» di cui al decreto ministeriale 17 gennaio 2018. Gazzetta Uffic iale, 11 February 2019. n. 35 (in Italian). Erdil E.F., Ozcelik R., Erdal F., 2024. External strengthening of RC structures with buckling-restrained braced frames. Bulletin of Earthquake Engineering, 22(4):1931 – 1963. Ferraioli M., Pecorari O., Mottola S., Diana A., 2025. Dissipative steel exoskeletons for seismic retrofit of RC buildings. Archives of Civil and Mechanical Engineering, 25(3), 134. Frappa G., Pauletta, M., 2025. Seismic retrofitting of a reinforced concrete building with unidirectional frames and low strength concrete Frappa G., Pauletta, M., 2022. Seismic retrofitting of a reinforced concrete building with strongly different stiffness in the main directions. Fib Symposium, Rome, Italy, pp. 499 – 508. NTC 2018, Ministero delle Infrastrutture e dei Trasporti. DM 17 gennaio 2018. Aggiornamento delle “Norme tecniche per le costruzioni”. Gazzetta Ufficiale, 20 February 2018. n. 42 (in Italian). Wilson, E. L. , 2002. Three‑Dimensional Static and Dynamic Analysis of Structures: A Physical Approach with Emphasis on Earthquake Engineering. Third edition, Computers & Structures, Inc., Berkeley.