Onsite experimental investigations into the qualification of materials and characterisation of dynamic structural behavior

Engineering studies have an increasing role to play in the process of preserving archaeological sites, in terms of both evaluation of the current conditions and prediction of seismic behaviour. The diagnosis phase is efficiently supported by non-invasive experimental procedures, which can either incorporate geometrical and material surveys through the inspection of structural components or evaluate the overall mechanical behaviour by means of numerical models calibrated on an experimental basis. This combination of punctual investigations and more comprehensive analyses is particularly suitable for the conditions of archaeological ruins, as they often show several vulnerabilities in terms of incomplete structures, discontinuities, deterioration and damage, and so on. Based on the historical information available on the Villa of Diomedes and the hypotheses concerning its transformation and development over the centuries, an experimental non-destructive test (NDT) campaign was planned, involving a collaboration between the Università degli Studi di Padova and the Università degli Studi di Napoli “Federico II”. Direct visual inspections, sonic pulse velocity tests and endoscopies were applied to several portions of the villa’s masonry to qualify its materials and structures. Test positions were selected according to the results obtained by the other disciplines involved in the knowledge process (e.g., stratigraphy and advanced 3D surveys) to combine the available data and achieve more comprehensive interpretations. Ambient vibration tests were also performed on the remnants of the villa at the Via delle Tombe level (ground floor) and on the lower-level portico (garden floor). The structural dynamic identification provided information on how vulnerabilities influence the mechanical behaviour of the villa. The main results of the research are described and discussed below.