Operational Modal Analysis in the Temple of Minerva Medica in Rome

The building, known as the Temple of Minerva Medica, dates back to the 4th century A.D. The building presents different critical aspects: first of all the monumental pillars rest on pre-existing archaeological sites and inhomogeneous layers of soils, moreover the integrity of the structure is endangered by severe vibrations induced by the frequent transit of the nearby trains and the local tramway. Due to the instabil- ity of the surviving portion of the dome (the main part collapsed in 1828), there were commissioned in 2012 by the “Soprintendenza Spe- ciale Archeologia Belle Arti e Paesaggio di Roma” relevant restora- tion and consolidation interventions. These works restored the majesty and reliability of this monument that is undervalued and often forgot- ten. Onsite testing gained a fundamental role in the identification of the construction, in particular, Ambient Vibration Test (AVT) pro- vides global information on the overall dynamic characteristics of the structures. This paper, through the case study of the Temple of Miner- va Medica, aims to prove the reliability of Operational Modal Analy- sis (OMA) in the identification of the dynamic behaviour of a large masonry building (natural frequencies, modal damping and modal de- formations). Two sets of measurements were recorded by the laborato- ry of Proof testing and Research on Structures and Material (PRiSMa) of the “Dipartimento di Architettura” of Roma Tre University. A rea- sonable number of accelerometers, were suitably positioned and the dynamic response of the structure to wind and the surrounding traffic was recorded; the measurements of the two halves of the temple were processed and later merged through the Multi-Run technique in order to identify the dynamic behaviour of the entire structure.