A Parametric HBIM Approach to Geometric Uncertainty Modelling for Heritage Bridge Structural Analysis

Implementing Historic Building Information Modelling (HBIM) for heritage structures is challenged by incomplete knowledge of hidden or inaccessible elements, as well as limited information on construction history, original design, and structural details, making geometric definition inherently uncertain. Simultaneously, applications such as structural analysis often require the same missing information. This study proposes an adaptive parametric Scan-to-BIM-to-FEM workflow that explicitly incorporates geometric uncertainty by generating multiple plausible and complete reconstructions from survey data and typological inference, enabling their use in parametric structural analysis. Starting from TLS survey, adaptive families were used to link measured and inferred dimensions through geometric constraints. The methodology is applied to the 19th-century masonry arch bridge of Montoggio (Genoa, Italy), currently characterized by a hybrid structural system resulting from subsequent retrofitting. Eight geometrical configurations were tested by varying uncertain parameters, including vault thickness and backing height, and were analyzed through modal and static finite element simulations. The results show a limited but non-negligible sensitivity of the structural response to these parameters, highlighting the influence of geometric uncertainties on analysis outcomes. In this light, the proposed framework provides a bridge between survey, modelling, and structural analysis, enabling HBIM to support interpretative and predictive structural assessment.