PSI - Issue 84

Domenico Liberatore et al. / Procedia Structural Integrity 84 (2026) 1151–1158

1158

This latter displacement is then compared to the displacement of the performance point, obtained by extending the elastic branch of the capacity curve until reaching the spectrum. The capacity/demand ratio obtained is equal to 1.65, well satisfying the Life-Safety limit state. Finally, the contour plots of the damage variable show a localization of damage in the central pier at the upstream side (Fig. 6a), in particular where the central arch connects to the pier, probably due to the slenderness of the two lateral sides of the arch in the out-of-plane direction. Additional damage is detected at the downstream side of the crowns of the lateral arches (Fig. 6b), and at the spandrels, highlighting the effect of the assumed boundary condition. 6. Conclusions The presented paper investigates the dynamic and seismic behavior of Pons Fabricius, an ancient Roman masonry bridge which connects Tiber Island and the left bankside of Tiber River in the city of Rome. The fundamental frequencies and mode shapes are evaluated by means of ambient vibrations measurements and OMA. A numerical model is developed from a 3D laser scanner survey, adopting a constitutive relation with damage. Due to the limited knowledge of material and soil properties, characteristic values from the Italian Standard Code are adopted, and these are recalibrated through a back analysis to reduce the average error evaluated over the first five frequencies. The numerical modal analysis provides, then, modal shapes in good agreement with the experimentally identified vibration directions, while moderate discrepancies are observed in the estimated modal frequencies, higher in the lower modes. Nonlinear static analyses are finally performed, revealing a predominant stiff and brittle structural response and highlighting the expected damage patterns, where a concentration of damage in correspondence of the abutments and the crown of the arches is found. Nevertheless, seismic demand-capacity checks over a Life-Safety limit state are fully satisfied, supporting the exceptional durability of Roman construction techniques over time. Acknowledgements This work was partially carried out within the research project “Complex and integrated survey methodologies. Documentation, Modeling and Communication of southern Campo Marzio (Circus Flaminius, Porticus Octaviae, Temple of Apollo Sosiano, Theater of Marcello, Fabricio Bridge) in Rome” funded by Sapienza University of Rome and Project PE 0000020 CHANGES – CUP B53C22003780006, NRP Mission 4 Component 2 Investment 1.3, funded by the European Union – NextGenerationEU. The opinions expressed in this publication are those of the authors and are not necessarily endorsed by the funding bodies. References Limongelli M.P., Turksezer Z.I., Giordano P.F., 2019. Structural Health Monitoring for cultural heritage constructions: a resilience perspective, IABSE Symposium , Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management, pp. 1552–1559. Brincker, R., Zhang, L., & Andersen, P., 2001. Modal identification of output-only systems using frequency domain decomposition. Smart materials and structures , 10 (3), 441. Guarneri M.E., Nisio S., 2021. «Le isole tiberine: storie di inondazioni, rappresentazioni topografiche e artistiche», Mem. Descr. Carta Geol. Ital. , vol. 108, pp. 233–246. [in italian] Inglese, C., Paris, L., 2020. Arte e tecnica dei ponti romani in pietra, pp. 15–57; 137–152 [in italian]. «Ponte Fabricio | sovraintendenzaroma». Available at: https://www.sovraintendenzaroma.it/i_luoghi/roma_antica/monumenti/ponte_fabricio «Ponte Fabricio», Turismo Roma. Available at: https://www.turismoroma.it/it/luoghi/ponte-fabricio DMIT. Decreto del Ministro delle Infrastrutture e dei Trasporti, 17 gennaio 2018. Aggiornamento delle “Norme tecniche per le costruzioni”. Gazzetta Ufficiale della Repubblica Italiana n. 42 del 20 febbraio 2018 , 2018. Taylor R.L, 2017. FEAP – A Finite Element Analysis Program, version 8.5. Addessi, D., Sacco, E., 2016. Nonlinear analysis of masonry panels using a kinematic enriched plane state formulation. International Journal of Solids and Structures 90: 194-214. Addessi, D., Liberatore, D., Nocera, M., 2022. Damaging behavior of masonry arch bridges: analysis of ‘Ponte delle Torri’in Spoleto, Italy. Journal of Earthquake Engineering , 26 (1), 449-474.