Traditional tools and modern technologies for the analysis of mansory structures: the case of the Church of Saint Andrea in Anagni

The assessment of the structural state of historical masonry buildings is a theme of urgent necessity for preserving the Italian and European Cultural Heritage. In this sense, this study, carried out in the framework of the 3rd International Summer School on Historic Masonry Structures (Anagni, 2021), intends to provide a schematic guideline for conducting preliminary analysis to evaluate the static behaviour of historic masonry buildings. In particular, the present work focuses on the case study of the Church of Saint Andrea in the historical centre of Anagni. The structural state of the church's principal elements is established starting from historical analysis and integrating with an accurate survey of the current crack pattern. A detailed survey carried out using the latest technology provides an accurate description of the church's geometry: of the exterior and the interior, which are used to study the state of the main arch, of the vault, and of the lateral lunettes. The analyses have been executed adopting traditional tools of the graphical statics, i.e., using Thrust Line (TL) approach and under the hypothesis of the Limit Analysis for rigid no tension materials. In this manner, no software is needed, and the structural state can be easily estimated. Without any claim of completeness for the case study, this work stands as a paradigmatic guide for people who intend to approach the stability check of historical buildings, integrating modern technologies with traditional instruments.