Monitoraggio delle deformazioni della cupola del Teatro Massimo di Palermo con l’impiego di tecniche topografiche e fotogrammetriche integrate.

This paper shows the first results of a study aimed at monitoring the deformations of the dome of the Massimo Theatre in Palermo caused by thermal dilatations, with the use of topographic and photogrammetric integrated techniques. Particularly, two robotic total stations and high precision digital photogrammetric systems were employed. In order to correlate the displacements of the rollers on which the steel structure of the dome rest with the thermal gradients, different thermal images were acquired. The main goal of the work was to compare the two techniques with reference to very small (sub-millimeter) deformation measurements. The obtained results show that the rollers are still working correctly. In fact, for a thermal gradient of 6 °C surveyed by thermographic camera, both topographic and photogrammetric techniques determined displacements of the order of 0.8 mm, according with the expected deformations of the theoretic model.