PSI - Issue 78

Maria Eleonora Pipistrelli et al. / Procedia Structural Integrity 78 (2026) 1911–1918

1918

5. Conclusions In this study, three different modelling approaches have been compared to evaluate their effectiveness in assessing the seismic behavior of a corner S.U. within a complex masonry aggregate. The selection of the configurations used in the modeling stage has been preceded by an historical overview of the aggregate's overall development, to establish how the corner unit historically evolved. Subsequently, surveys have been carried out on the material and floor properties of the entire aggregate and the corner portion. The crack pattern obtained from a visual inspection of the north-east portion has also been documented in detail. Based on the information gathered, the north-east corner has been identified as a distinct structural unit embedded within the aggregate. The next phase has involved testing various modeling strategies to assess its seismic response. Starting from an isolated S.U. model, additional configurations have been developed to simulate the influence of adjacent units, either by explicitly modeling portions of the neighboring buildings or by introducing constraints representing their effect in terms of stiffness. All models have been developed using the equivalent frame method and analyzed through nonlinear static analyses. As expected and consistent with findings from similar studies, the inclusion of adjacent units has led to an increase in the ultimate base shear capacity, while displacement capacity decreased. Notably, the damage pattern resulting from the third configuration has more closely resembled the real crack distribution observed in situ. This confirms that including a limited extent of the surrounding aggregate is sufficient to improve the accuracy of the simulation, without requiring the modeling of the entire complex. Therefore, modeling the S.U. along with a portion of the neighboring units has proven to be the most effective and computationally efficient approach for the investigated case study. References Pellegrini, P., Micelli, E., 2019. Paradoxes of the Italian Historic Centres between Underutilisation and Planning Policies for Sustainability. Sustainability, 11, 2614. Pinasco, S., Lagomarsino, S., Cattari, S., 2025. Unreinforced masonry buildings in aggregate of urban settlements: Current approaches and critical issues for the seismic vulnerability assessment. Structures, 73, 108335. Celetti, D., Bozhko, L., Avetisyan, R., 2023. Industrial Districts and Industrial Clusters. Conceptual Approaches from Italian and Eurasian Experiences. In: Martinat, S., Kumar, V., Torre, A., Lavrikova, Y., Kuzmin, E. (eds) Landmarks for Spatial Development. Contributions to Regional Science. Springer, Cham. Chieffo, N., Formisano, A., Lourenço, P.B., 2023. Seismic vulnerability procedures for historical masonry structural aggregates: Analysis of the historical centre of Castelpoto (South Italy). Structures, 48, 852-866. Angiolilli, M., Brunelli, A. Cattari, S., 2023. Fragility curves of masonry buildings in aggregate accounting for local mechanisms and site effects. Bulletin of Earthquake Engineering, 21, 2877–2919. Acito, M., Buzzetti, M., Cundari, G., A., Milani, G., 2023. General methodological approach for the seismic assessment of masonry aggregates, Structures, 57, 105177. Di Trapani, F., Villar, S., Di Benedetto, M., Petracca, M., Camata, G., 2024. Seismic response of unreinforced masonry building aggregates: Investigation on the “aggregate-effect” based on an elementary building aggregate. Engineering Structures, 316, 118301. Formisano, A., Massimilla, A., 2018. A Novel Procedure for Simplified Nonlinear Numerical Modeling of Structural Units in Masonry Aggregates. International Journal of Architectural Heritage, 12, 1–9. Battaglia, L., Ferreira, T., Lourenco, P. B., 2020. Seismic fragility assessment of masonry building aggregates: A case study in the old city Centre of Seixal, Portugal. Earthquake Engineering & Structural Dynamics, 50, 1358-1377. Valotto, C., Taffarel, S., Marson, C., Munari M., da Porto F., Modena C., 2016. Seismic vulnerability assessment of corner buildings in the historical centre of Timisoara. Brick and Block Masonry: Trends, Innovations and Challenges - Proceedings of the 16th International Brick and Block Masonry Conference, IBMAC 2016, 2499 – 2506.