The Bell Tower: the facts-finding pathway and good practice for the structural diagnostic analysis

Specific characteristics of single heritage constructions pose a challenge at the moment of the formulation of a judgement on the preservation state and safety of the object. In Italy, the guidelines on assessment and reduction of seismic risk to heritage constructions have provided a procedure for gaining an adequate level of knowledge of masonry constructions. Such operative methodology is presented as a path made of many aspects that, at different levels and from many viewpoints, should bring together a detailed qualitative and quantitative knowledge of the artifact under analysis. Knowledge steps include the search for documents and information from various sources, visual inspections, surveys and non-invasive diagnostic approaches, structural numerical modelling. Nevertheless, these guidelines are necessarily a generic document and cannot detail many practical aspects so that the professional dealing with real cases has to rely on extensive knowledge and experience. This is particularly true in the case of peculiar typologies of constructions, such as ancient masonry towers, which – due to their geometry - present extra problems of accessibility, inspection and survey. This thesis looks at a number of medieval masonry towers with steeple masonry spires located in Piacenza and Ravenna, Italy, to test on-site a multidisciplinary, coherent facts-finding path that keeps into account the characteristics and problematics of the single constructions in order to reach a reliable evaluation, drawing from the examination of the collected info and produced data. At the same time, this thesis aims to consolidate the author’s knowledge about the most correct choice and procedural application of various techniques according to the specific aims, in view of her professional future, keeping in mind both the engineer’s viewpoint of building safety and the architect respect for the heritage value.