Multiscale and multisensor approach for the structural diagnosis of ancient buildings: the case of the "Domus of the Silver Wedding" in Pompei.

Monitoring of ancient buildings is an issue of great interest in view of a proper restoration. Among the monitoring techniques, the non-invasive ones used in an integrated way are particularly suitable [1,2], if not mandatory, if we need to investigate weak structures whose cultural value and brittleness entails the impossibility of invasive tests, as in the case of the Domus of the Silver Wedding in Pompei. The roman house, as occurred for many other buildings in Pompei, was buried in the ash from the 79 AD eruption of Mount Vesuvius. It was excavated in 1893, the year of the silver wedding anniversary of King Umberto and Queen Margherita of Savoy. This event gave the name to the roman domus whose excavations uncovered a monumental architecture composed of an atrium, and two gardens. The atrium is characterized by four tall Corinthian columns and an elegant exedra with fine decoration. Of the two gardens, one, the larger, includes a central pool and a triclinium, the other one is composed of a bath-house, open-air swimming pool and a living room embellished by a mosaic floor and wall paintings. From the archaeological record it was possible to find a foundation phase dating back to around 300 BC and a following phase of renovation in the 1st century AD when the domus belonged to a wealthy owner of Pompei. The domus has a long history of works which allowed to restore the architectural integrity partially lost due to the damage caused by the 79 AD vulcanic event. Over time the weathering and the presence of heavy and rigid concrete structures have caused some static problems to be addressed by restorations respectful of the mechanical behavior of the original load bearing framework. To this aim a multisensor approach based on the use of a number of non invasive in situ tests, including georadar, seismic investigations, infrared thermography, has been adopted to collect data useful for the structural diagnosis. The survey has been performed by laser scanner and images taken from drone processed by structure from motion algorithms in order to provide a 3d textured model functional to finite element model processed with two different computing codes. Finally, the results put in evidence the great effectiveness of an approach based on the processing and interpretation of data acquired by different sensors at different scale.