Per una manutenzione mirata di sistemi complessi: uso di un modello spaziale come strumento operativo per la pubblica amministrazione.

Planned maintenance is becoming more and more the way to face the problem of avoiding random or casual repair interventions, which often become emergency measures due to an increasing and progressive decay that menaces to endanger definitely the integrity of an artefact. Programming maintenance interventions on a many years scale become mandatory when the heritage to preserve shows features of huge material and geographical extent, as in the case of particular monumental sites. The examined case refers to the wall circle of Bergamo, but the argument can be also discussed in reference to some historical country houses or else to urban or landscape sites.
From this point of view, the preliminary knowledge phase plays a fundamental role in order to develop suitable and effective intervention strategies, focusing on one side on the detection of recurring problems, on the other on finding the critical zones where particular care must be applied, establishing also a priority ranking for employing the allowable (and often limited) economic resources. Very effective appears the use of aerial photogrammetric survey by UAV, thanks to the powerful software instruments that nowadays can be used, allowing nearly short-distance shooting that can lead to build detailed digital models of the surfaces of observed artifacts and the examination of their conservation conditions.
A recent example of the application of this technique to a particularly interesting object is the survey campaign developed in the framework of the maintenance project on ‘Venetian Walls’ of Bergamo. It is also a good example of collaboration among Public Administrations (the Municipality of Bergamo and the University) and private associations, like ‘Orobicambiente’ and ‘Italia Nostra’, involved in the conservation and protection of the heritage and the landscape. In July 2017, the ‘Venetian Walls’ were registered in the UNESCO World Heritage List as part of the serial multinational site Venetian Works of Defense between 16th and 17th Centuries: ‘Stato da tera’ – Western ‘Stato da Mar’. In the meantime, the Municipality of Bergamo began a project for setting up a maintenance program for the Walls in order to fight and contain the deterioration processes, with the scientific support of the University of Bergamo and the economical contribution of ‘Fondazione CARIPLO’. A series of actions aimed to the “sustainable maintenance, conceived as a daily treatment process of different architectural elements that compose the stone landscape of the Venetian Walls”. Conservation interventions are anticipated by an analytical phase that will be repeated recursively, including direct in situ inspections and systematic explorative investigations (with the cyclic monitoring of the material deterioration by means of 3D aero-photogrammetric survey using drones).