IL LASER SCANNING TERRESTRE PER L'ANALISI DI EDIFICI DI INTERESSE STORICO ED ARTISTICO

Identifying the overhang, progressive changes of inclination, differential movements of the structure and detailing the study of structural elements are just some examples of the many fundamental and necessary information for structural engineers. Those data are required to study and analyze the behaviour of a structure with the purpose to assess the stability . Looking at the several methods offered by Geomatics, laser scanning appears to be the best technology to provide an effective solution to those requirements. Surveying by means of a terrestrial laser scanner, allows to detect a huge number of information with relatively short time and high accuracy. Those data, then, do not necessarily need to be used to reconstruct the three dimensional surface model. Just analyzing the point clouds, interesting information along with useful products can be obtained in order to draw some considerations about the investigated structure.This research aims to suggest a new philosophy for using the laser scanner in a diagnostic perspective in order to study structures along with their actual dimensions, their stability and so on. This new approach, characterized by a well-advanced vision, is very different from the traditional one because of the engineering point of view with respect to the usual application of laser scanner. Traditionally, indeed, laser scanning is chosen for artistic and architectural studies and the resulting three-dimensional model represents what often is of concern. Some case studies will be presented; they are characterized by different kinds of structures suffering from various problems: the Cathedral of Modena and the Ghirlandina Tower UNESCO-World Heritage (Italy), "della Sagra" Tower in Carpi (Modena – Italy) and Asinelli Tower in Bologna (Italy). The final purpose is to illustrate the methodology to perform the structural analysis by means of terrestrial laser scanning. Furthermore, examples will be presented about extraction of interesting products and results.