Computational 3D modeling supporting the preservation of historic timber roofs: the case of San Pietro’s Cathedral in Bologna

Preserving structural elements of heritage buildings is crucial for conserving their cultural value. Non-invasive diagnostic methods are required in restoration design to assess historic constructions without executing costly in-situ tests that could damage their architectural image. The recent spread of digital tools in the Cultural Heritage (CH) sector has shown innovative procedures for the knowledge of existing buildings based on different approaches from traditional methods. This paper presents the last update of a research project set up to evaluate the displacements and deformations of old timber trusses. It is based on geometrical data about the current state of trusses, which are surveyed by Terrestrial Laser Scanning (TLS) and processed by computational 3D modeling techniques. The research has been applied to several wooden roofs covering some masonry architectures built in Bologna (Italy) from the 16th to the 18th centuries. This latest step focuses onthe roofing system of San Pietro’s Cathedral. With a span of about 26 meters, its timber roof trusses are among the largest in Europe. The application of the proposed workflow allowed comprehending the behavior of the Cathedral’s roof structures and suggesting some hypotheses for conscious maintenance and conservation.