GPR application to the structural control of historical buildings: two case studies in Rome, Italy

Preservation of historical buildings requires particular care, as any intervention must not alter or damage the style, structure or contents of the edifice. In order to properly plan the restoration of a building, non-destructive techniques can be used extensively to detect structural elements and weaknesses. Ground-penetrating radar (GPR) is particularly well adapted to this type of work, as the method is non-invasive, rapid and provides high-resolution images of contrasting subsurface materials. In the present work we show the successful application of the GPR technique to the investigation of two historical buildings that differ in age, structure and geometry. The first case is the GPR detection of fractures and internal lesions in the architrave of the Porticus Octaviae, a partially restored Roman building. The second case uses GPR in the important Zuccari Palace to determine the internal structure above vaulted ceilings that host a series of 16th century frescos. Both buildings are located in downtown Rome, Italy. These examples show that GPR can give detailed, non-invasive data that describe the state of conservation of historical buildings. In particular, this technique can produce fundamental information for the restorers (e.g., location, dimension and geometry of the structural lesions) that will help them develop the best possible protection plan, retrieving quantitative information about the location and the dimension of the lesions as well as the thickness of the different layers