PSI - Issue 78

Danilo D’Angela et al. / Procedia Structural Integrity 78 (2026) 1617–1624

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Fig. 5. Capacity surfaces, based on fragility medians (x M ), expressed in terms of dimensionless peak ground acceleration (PGA*) as a function of limit dimensionless rocking amplitude angle (|θ max /α| lim ) and semi-diagonal block dimension (R), considering strong floor motions (SFM). 4. Conclusions This work reported an applicative framework for evaluating the seismic capacity of unanchored nonstructural elements (NEs) whose response is primarily governed by rocking dynamics, according to a recently developed methodology (D’Angela and Magliulo, 2025) . The proposed methodology incorporates fragility surfaces that capture the effects of floor-level motion modifications due to building dynamic behavior, such as filtering and magnification effects. A broad set of incremental analyses was carried out on rigid block models, accounting for diverse geometries, seismic intensity measures, and progressive damage levels. Closed-form surface capacities are provided, enabling rapid estimation of median capacity and associated variability. Further studies should experimentally validate the provided capacity curves, as well parametric studies should provide corrective factors to extend their validity of nonsymmetric blocks or more complex case study NEs. Acknowledgements The study was funded by (a) the European Union - Next-GenerationEU – Piano Nazionale di Ripresa e Resilienza (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO N. 1.1, BANDO PRIN 2022 PNRR D.D. 1409 del 14-09-2022 (ROCK-RESILIENCE: ROCKing-based strategies for RESILIENCE of reinforced concrete structures: conception, structural design, nonstructural components, efficiency and sustainability) CUP N.E53D2301704001, (b) the Italian Ministry of University and Research (MUR) in the framework of PRIN 2020 project titled “ENRICH project: ENhancing the Resilience of Italian healthCare and Hospital facilities”, and (c) the Italian Department of Civil Protection (DPC) in the framework of the National project DPC – ReLUIS 2024-2026 WP17: “Componenti non strutturali”. References Applied Technology Council (ATC), 2008. ATC 63. Quantification of building seismic performance factors. California. Argenziano, M., Cutolo, A., Babilio, E., Carotenuto, A.R., Fraldi, M., 2023. Moving mass over a viscoelastic system: asymptotic behaviours and insights into nonlinear dynamics. Nonlinear Dyn 111, 12033 – 12052. https://doi.org/10.1007/s11071-023-08465-z