Un protocollo per la classificazione dei danni strutturali e la valutazione della loro evoluzione: sviluppo in ambiente HBIM

The interpretation of crack patterns, together with the assessment of their severity, represents a fundamental step in the analysis of the structural stability of masonry buildings and, consequently, in the conservation of the architectural heritage. The topic falls fully within the scope of architectural conservation, since the survey and critical analysis of structural damage require an in-depth understanding of the building’s history, construction feature, and transformations, in order to understand their effects on the resulting damage patterns. Historic Building Information Modelling (HBIM) offers valuable support for the representation and interpretation of damage, as it enables: precise spatial localization, the association of descriptive information useful for classification, and the correlation with other relevant factors. However, the crack mapping in HBIM environment remains an open issue due to the lack of appropriate tools and shared methodologies. Regardless of information systems, damage classification still represents an open field of research from a methodological point of view. Despite the acknowledged importance of the topic – also recognized by cultural heritage regulations (D.P.C.M., 9 February 2011) – there is still a lack of standardized protocols for the classification of crack patterns, which must be critically analyzed to identify the most probable damage mechanism. Nevertheless, cracks can be effectively classified, as they exhibit recurrent morphologies that are characteristic of the ongoing kinematic mechanism, although they are influenced by multiple factors, including the construction and geometrical features of both individual elements and the overall building structure, as well as the transformations occurred over time. Crack morphology can be described through specific parameters (direction, variation in width along its development, depth, etc.), while typical crack patterns can be associated with different types of kinematics (such as rotation or vertical translation), actions (compression, shear, etc.), and categories of structural elements. This research proposes a protocol, implemented within the HBIM environment and aimed at the information-based representation and guided analysis of damage. The method is based on the identification of the descriptive parameters of cracks and on querying a structured database developed to support diagnostic analysis. This process enables the abstraction of the kinematic mechanism associated with the damage – based on its morphological features – and the identification of the macroelement involved, according to positional data and correlated crack patterns. The proposed database also supports etiological diagnosis by facilitating the identification of potential causes through the listing of contributing factors. Finally, the research offers a critical reflection on the extent to which the process can be automated through information systems, and on the stages that, conversely, still require the expert’s interpretative input. The methodological framework is completed by the integration of monitoring data, which are essential both for validating diagnostic hypotheses and for assessing the evolution of damage over time. For this purpose, synthetic indices are proposed to quantify data reliability and damage progression, which are fundamental for estimating overall damage severity. The proposed protocol has been validated through its application to two case studies, for which HBIM models are developed: Palazzo Pallavicino, a representative example of a historic building with a typical and well-documented crack pattern, and the Dome of Santa Maria del Fiore, a case of exceptional complexity in terms of geometry, damage characteristics, and monitoring system configuration.