Different analysis strategies in the structural assessment of the St. Anne of Pietra Perduca oratory

The paper deals with some open issues about direct investigations and structural analysis related to the conservation of the architectural heritage. At first, it discusses the theme of the importance of the direct investigation on the monument, aimed to a full and conscious knowledge of the building. Then it focuses on structural analysis, which is based on the information obtained by means of surveys and it is not just an act for the project, but becomes itself an instrument of knowledge, that must be integrated with all other methods of investigation. The work focuses on the case study of the Oratory of St. Anne of Pietra Perduca, located in the Trebbia valley, close to Piacenza (Italy). The masonry of the building is made of marly limestone ashlars. These ashlars were laid with mortar placed into the wall’s interstices and not visible on the external face, giving impression of dry masonry. The pitched roof has a timber structure with trusses and limestone roofing. Different structural analysis techniques were used for the structural assessment on the different building elements. For the timber roof structure linear static analysis was used, while for the masonry triumphal arch and the presbytery vault graphical methods, starting from Mery’s and Heyman’s formulations, were followed by a detailed numerical study by means a nonlinear macro-element non-linear modelling.