Per un calcolo “di qualità”: storia di una sfida qualitativa alla quantificazione, passando per la conoscenza

Starting from the case study of a 16th century palace in Parma, this paper aims to demonstrate how a careful constructive survey, together with an accurate investigation of the historical evolution of the building can, in certain cases, avoid the need to resort to invasive mechanical tests for safety assessment. This challenge is based on the awareness, resulting from a long debate in the academ ic and scientifc felds, of the importance of the ‘knowledge path’ in the analysis of the structural behavior of historic masonry buildings: the ‘qualitative understanding’ of the building – gained through the direct and in-depth knowledge of the asset, the constructive features, the proportional rules, the historical evolution, as well as the experience of recurring damage – is the basis for a correct evaluation of strengthening interventions and, sometimes, unexpectedly, is even preferable to numerical data. In fact, it is widely recognized, even in the normative feld, that standard global modeling procedures and numerical calculations, valid for ordinary buildings, do not always ft for historic masonry structures, which tend rather to be damaged by local mechanisms. In fact, the path of knowledge, applied to the case study, which will be illustrated in this paper, allowed to highlight the main vulnerabilities of the asset and therefore to focus on the direct investigations only on the elements at risk, for which local interventions will be planned, respecting the principle of minimum intervention.