The management of the restoration site. Diagnostic techniques, problems and perspectives

In the restoration site the uncontrolled evolution of the design phase linked to unexpected and unpredictable causes is now experienced with resignation. These changes open unexpected scenarios that must be supported through a solid and integrated knowledge system capable of providing new readings and new interpretations of the work. This is essential to promptly reformulate an action plan able to bring the project to its original goal or to reach a new one. The restoration site is the occasion for quite complex analysis and studies, especially in the case of historic buildings that are affected by constant and substantial changes over the centuries. From the beginning the restoration work has to face: unexpected and unpredictable situations, which are the result of the progress of the work itself, the correct and detailed definition of the solutions to be implemented and the urgency of finding funds for the work. It is therefore necessary to proceed, on the one hand, to the continuous updating of knowledge, with specific insights, and on the other to the identification of shared solutions. These must take into account both the conservation and protection issues and the more practical and functional aspects, in order to support operational decision-making for the resolution of crucial nodes of the intervention. The risk, however, is the fragmentation of the intervention and the drift of the original plans. In defining the design choices, the chronological study of the structures, carried out using stratigraphic methods and enriched by the detailed analysis of the materials and construction techniques, and the highly accurate 3D relief are essential support tools. Furthermore, a HBIM approach, supported by 3D surveying performed using a Terrestrial Laser Scanner, can be strategic in a conservation and restoration project in which multiple specialized skills are called to integrate and coordinate themselves in order to achieve a common goal in terms of quality, costs and time. Starting from these premises, a first experimentation focused on the implementation of the HBIM approach for the management of the historical architectural heritage of Sardinia was carried out. For a selected case study, an information model was developed as the combination of virtual digital components, that faithfully represent the real objects of the building. Within the digital “twin” of the building all data and information acquired in the different phases of the study have been structured. The information model obtained allows an efficient management of the transformation/conservation intervention, guaranteeing an effective archiving of the documentation of the initial state of the building, the studies conducted, the results obtained and, finally, the achieved results. This experimentation is a first step towards the evolution of restoration processes in terms of effective coordination between restoration experts, geomatics, materials and diagnostics, construction techniques, as well as building processes. This coordination is essential and advantageous as it guarantees a significant reduction in working time compared to higher quality. This process does not end with the realization phase, but the model created, strongly dynamic, continues to be used and integrated for the rational management of the building and for the planning of its maintenance