Displacement and deformation assessment of timber roof trusses through parametric modelling. The case of San Salvatore’s church in Bologna

The article investigates wooden trusses and their evolution over time, through the re-elaboration and interpretation of the data obtained through a laser scanner survey. From the point cloud of the entire roof, 3D models of the individual trusses are obtained through reverse engineering software and parametric modeling. Each model is rendered by setting robust constructive and evolutionary hypotheses to which these structures must respond and represents a regression over time of the truss from the “current” to the “original” condition. 3D models, therefore, become a reasonable representation of the original condition. Therefore, by comparing the models with the point cloud, it is possible to analyze these trusses in detail, highlight their movements and deformations, obtain precise and comparative information on their behavior and draw global considerations on the health of the entire roof.