La qualità nel consolidamento dell’architettura storica: il ‘percorso di conoscenza’ per il progetto strutturale

The well-known ‘knowledge pathway’ that the Guidelines for Seismic Risk Assessment and Reduction of Cultural Heritage define for estimating the structural safety of constrained historic buildings expresses the reciprocal and obligatory relationship that must exist between the cognitive tools in use in conservation and the analytical fallout employed in the consolidation project. The Guidelines, therefore, through the ‘quantification’ of knowledge in terms of ‘confidence coefficient’, establish a sequential relationship between the degree of understanding gained and the numerical verifications. In this sense, the deeper the ‘confidence’ with the building – through the geometric survey and the crack and deformation picture, the study of the phases of transformation, the understanding of the mechanical properties of the materials and the knowledge of the geometry of the foundations and the geotechnical parameters of the ground – the more the calculation procedures succeed in approximating the actual behaviour of the historic structures, a condition on which the characteristics and quality of the intervention solutions depend and benefit. Based on this premise, the paper intends to reflect on the decisive role of the standard and its proper application, on the occasion of its alignment with the updated Technical Standards for Construction 2018 and its explicit extension to unrestricted historic buildings. The illustration of some case studies, moreover, will be considered to describe how conservation knowledge tools are able to foster a greater and more relevant connection between historical-constructive awareness and structural safety.