GPR investigations at San Francesco di Paola ai Monti, Rome

The St. Francis of Paola ai Monti church in Rome is an important historical building, currently (as of December 2024) closed to the public because of ongoing damage patterns causing structural damage (mainly cracks and fissures [1]). In view of the 2025 Jubilee, the Department of Environmental Engineering (DIAm) of the University of Calabria (Italy) was put in charge of geotechnical and geophysical analyses in order to assess the status of the building, understand the main causes of the ongoing structural problems, and address scientifically-informed restoration and retrofitting actions. In particular, we performed a Ground Penetrating Radar (GPR) investigation of the main nave and of three chapel on the right hand side looking toward the altar (this side is the most affected by fractures in the masonry). The investigation, as it often happens [2-4], has revealed several structural anomalies of cultural interest ascribable probably to tombs and mass graves. Some of these anomalies were deducible from inscriptions on the floor, while some others were not revealed by external traces. The data have been elaborated according to a well assessed linear data processing [5-6] and have also revealed the different consistency of the subsoil under one of the lateral chapels, which is coherent with the structural problems.Key words: Structural investigations, cultural heritageReferences[1] P. Zimmaro, E. Ausilio, Geotechnical and structural investigation and monitoring techniques to determine the origin of ongoing damage processes in historical buildings: The Saint Francis of Paola Church in Rome case history, Geotechnical Engineering for the Preservation of Monuments and Historic Sites III – Lancellotta, Viggiani, Flora, de Silva & Mele (Eds), CRC Press, Napoli (Italy), June 22-24, 2022. DOI: 10.1201/9781003308867-47.[2] R. Persico, S. D’Amico, L. Matera, E. Colica, C. de Giorgio, A. Alescio, GPR prospecting within the chapel of Aragon within the co-cathedral of St. John in Valletta, Malta, Proc. of 17th International conference on Ground Penetrating Radar, Rapperwil, Switzerland, June, 18-21, 2018.[3] A. Calia, G. Leucci, M. T. Lettieri, L. Matera, R. Persico, M. Sileo, The mosaic of the crypt of St. Nicholas in Bari (Italy): Integrated GPR and laboratory diagnostic study, Journal of Archaeological Science, vol. 40, n. 12, pp. 4162-4169, December 2013.[4] M. Pieraccini, L. Noferini, D. Mecatti, C. Atzeni, R. Persico, F. Soldovieri, Advanced Processing Techniques for Step-frequency Continuous-Wave Penetrating Radar: the Case Study of “Palazzo Vecchio” Walls (Firenze, Italy), Research on Nondestructive Evaluation, vol. 17, pp. 71-83, 2006.[5] R. Pierri, G. Leone, F. Soldovieri, R. Persico, "Electromagnetic inversion for subsurface applications under the distorted Born approximation" Nuovo Cimento, vol. 24C, N. 2, pp 245-261, March-April 2001.[6] I. Catapano, L. Crocco, R. Persico, M. Pieraccini, F. Soldovieri, “Linear and Nonlinear Microwave Tomography Approaches for Subsurface Prospecting: Validation on Real Data”, IEEE Trans. on Antennas and Wireless Propagation Letters, vol. 5, pp. 49-53, 2006.