MULTIDISCIPLINARY APPROACH TO THE STUDY OF THE STRUCTURAL EVOLUTION OF PALAZZO VECCHIO FLORENCE (ITALY)

Historic buildings are elements of great complexity, shaped by history. They are the result of long evolutionary processes and not of a single construction phase, because of their characteristics, they require particular attention in the reconstruction of their architectural and structural evolution. The urban area of Palazzo Vecchio, Florence Italy, is a site of extraordinary historical importance, built in Roman times, late antiquity, early and late medieval, Renaissance and modern. The Palagio dei Priori, designed by Arnolfo di Cambio, in 1299, constituted the first core of the Palace, which has always been the seat of the city government. The administrative needs of the Florentine Republic, before, and later for the Lordship, Grand Duchy and in the XIX century for Florence Capital of Italy and now as City Hall, required the palace to expand until it occupied the whole block. The final objective of the research program, the definition of the seismic behaviour of Palazzo Vecchio, needs to know construction phases in order to define homogeneous structural blocks on which to direct the survey campaigns on the consistency of the materials of the walls and on the dynamic behaviour of the structure. The knowledge of the building cannot be separated from the historical analysis of the functional evolution of the building and its structural articulations, and in the case of Palazzo Vecchio particular attention must be paid to the fact that it was erected onto Roman and Early Medieval ruins and not directed rooted in the subsoil. In order to evaluate the seismic vulnerability of a building, a full knowledge of the structure is required, also obtained through on-site survey campaign, which terms for buildings of cultural heritage is defined by the Ministery for Cultural Heritage guidelines (MiBACT 2011 rule). This on-site survey campaign must not to be too invasive and harmful and asks for techniques based on a multidisciplinary research approach for defining the knowledge of the structural evolution and of the characteristics of the materials. Therefore, only architectural survey, historical research and non-destructive investigations (NDT), as Georadar, thermic, microendoscopy, sonic, ultrasonic and local small unplaster can be performed.