LASER MODELING AND STRUCTURAL ASSESSMENT OF A XVIITH CENTURY WOODEN DOME

The main room of the Valentino Castle in Torino, the “Salone delle Feste”, was conceived and realised in the XVIIth century under the guidance of Carlo di Castellamonte. The beautiful frescos and stuccoes of the domical vault are sustained by a typical Delorne carpentry, whose span is among the largest of their kind. The dome suffered from degradation during the years, and a series of interventions were put into place. Nowadays, a survey revealed that the suspender cables above the vault in the region close to the abutments have lost their tension. This may indicate an increase of the vault deformation; therefore a structural assessment of the dome is mandatory. In order to reinforce the structural hypothesis of damages and to reveal the deformation effects, a high detailed metric survey have been carried out with integrated laser scanning and digital close range photogrammetry. The photogrammetrical survey of frescos, with the re-projection of images on vault surface model (texture mapping), is purposed to exactly localize formers restoration and their signs on frescos continuity. The present paper illustrates the generation of the 3D high-resolution model and its relations with the results of the structural survey; both of them support the Finite Element numerical simulation of the dome. Finally, possible intervention techniques are mentioned, accounting for the restoration criteria of reversibility, minimum intervention, sustainability and compatibility.