Use of the transmissibility function H for ambient vibration measurements of an archeological building

The present paper illustrates the use of the transmissibility function H with several approaches and formulated in different ways to analyze ambient vibration measurements of an archeological building. The use of H as a consolidated estimator of the frequency response function (FRF) of the studied structure, can take advantage of its application also to other approaches, such as the horizontal-to-vertical spectral ratio (HVSR) approach. In fact, in the case of ancient masonry and ruined buildings, characterized by high heterogeneities and complexities, modal estimators computed from on-the-field data are typically quite noisy, so that accurate identification of the analyzed structure is sometimes challenging. Through a mutual validation of the results by several methods useful indications on the reliability of findings can be provided. To such purpose, also operational modal analysis (OMA) was performed and compared to modal identification by H function. A practical application to the so-called temple of Minerva Medica, located in Rome, was described.