Seismic Vulnerability Assessment in HBIM Models of Historical Masonry Buildings Using IFC Standard

Historical masonry buildings frequently exhibit structural cracks, poor interlocking, or structural discontinuities, resulting from complex construction processes. These conditions trigger out-of-plane collapse mechanisms of wall portions (macroblocks) during seismic events. Reliable vulnerability assessment must consider such defects, and in complex cases, 3D modeling enriched with diagnostic information can support the identification of hazardous scenarios. Historical Building Information Modeling (HBIM) is effective in documenting the “as-is” state and, to transform HBIM into an active tool for restoration planning and seismic risk mitigation, an enriched data structure is required. The Industry Foundation Classes (IFC) standard provides such a framework, enabling the integration of survey and preliminary structural evaluation within an interoperable environment. The proposed OpenHBIM methodology systematically encodes crack patterns and discontinuities in IFC, decomposes the structure into macroblocks, and supports semi-automated assessment of out-of-plane mechanisms through limit analysis. A Python-based algorithm processes the model, enriches its semantic data, segments damaged walls, and assigns analytical properties for structural evaluation. The approach is tested on Villa Gazzotti-Grimani (Italy), where 14 macroblocks are evaluated according to current standards. Results are encoded in IFC, demonstrating effectiveness for preliminary assessments also adaptable to other contexts, while highlighting limitations due to the rigidity of the IFC schema.