Stratified masonry building and cracks analysis. A case study

The research deals with a case-study which offers interesting evidences on the role of the knowledge of the construction and transformations phases of a historical building in order to better delineate the vulnerable elements of structures and the interpretation of cracks. The case-study is a fortress in Modena (Italy) transformed in the 17th c. into a noble palace; specifically, the research is focused on the investigation of the structural damages in the grandstaircase. Behind the outward image of the palace, the surveys on masonries allowed to understand the complex sequence of construction events that predated the current arrangement. These investigations, and the survey on the construction techniques used over time, pointed out a more complete framework where damages can be better understood. Moreover, this wider context suggests limits and potentialities for future strengthening interventions: once reconnected to their historical meanings, these signs, apart from possible vulnerabilities, become also material documents to preserve.