The Knowledge Process in the Seismic Assessment of Masonry Building Aggregates – An Italian Case Study

The recent seismic events occurred in Central Italy have rekindled the attention toward the safeguard of historical cities by leading to a renovated debate within the academic community regarding specific aspects of the seismic vulnerability and their protection. The study of masonry building aggregates is certainly one of these aspects, since they represent a typical urban configuration of the Italian but also European historical towns. Because of their constructive and evolutionary history, masonry aggregates are a complex assemblage composed of units with different periods and techniques of construction, materials and structural details, which, all, contribute to the seismic response of the whole. Therefore, the assessment of the seismic vulnerability of aggregates has to start necessarily from a process of knowledge able to provide a set of reliable input data useful for the subsequent development of numerical models employed for structural analysis. The main goal of the paper is to present a procedure for the seismic assessment of masonry building aggregates toward the most common out-of-plane failure mechanisms generally observed during seismic events. The main feature of the proposed procedure is a multi–level input-analysis-output approach, combining the level of detail of the input data, deduced from the knowledge get by a survey process, at the level of detail of the output thus obtaining a refinement of the numerical models. The procedure is applied to the case study of Borgo San Rocco in Sora (FR), a historical center located in Central Italy.