Integrated study of the Beata Vergine Assunta dome with structure from motion and diagnostic approaches

Between 1839 and 1849, the architect Gaetano Cima built a very interesting neoclassical church with a central plan, covered by a dome about 20 meters in diameter in Guasila (in the province of Cagliari, Italy). Already during the construction, Cima highlighted a series of problems related to the quality of the materials used, the technical skills of the builders, and the cost-cutting measures taken during construction, which proved to be the cause of the deterioration that characterised the life of the building and the numerous restorations works that have occurred over time. Faced with this situation, the Municipality of Guasila has commissioned a group of researchers from the DICAAR (Department of Civil, Environmental and Architectural Engineering) of the University of Cagliari to carry out a multidisciplinary study aimed at defining in a complete and exhaustive way the state of conservation of the church. Overall, this study concerned historical-critical analysis, geometric-Architectural survey, structural survey and analysis, analysis of materials and the study of foundations involving architectural historians, geomatics, structuralists, petrographers and geophysicists.In detail, this paper presents the integrated results obtained from archival research on the restoration works, the close range photogrammetric (CRP) and minero-petrographic surveys performed for implementing the knowledge of the painted dome of this basilic, characterised by several static problems since its construction. The support of the three fields of research has allowed not only to define an in-depth level of information concerning the origins of the issues in terms of geometries, materials and building techniques for the design of future interventions of conservation of the structures, but also to define potentialities and accuracy of this interoperable approach in the study of other similar case studies.