A Macroelement Numerical Analysis for Seismic Vulnerability Estimation and Retrofit of a Complex Masonry Aggregate

Masonry buildings in historical sites are difficult to analyse as independent structures since they typically have common walls with adjacent structural units. Whenever seismic forces interact with these categories of building compounds, their behaviour differs from that of individual buildings considered as independent structures. The research examines in detail a simplified methodology for analysing the vulnerability of masonry building aggregates presenting a case study in Castelpoto, a municipality of Benevento (Italy). The investigated structure is an existing masonry building compound with a non-regular configuration consisting of seven structural units, SUs. Specifically, three SUs are placed in the head position, two cells are in the corner position and the other two cells are enclosed between two adjacent SUs. The vertical structure has an irregular stone texture, while the horizontal structural components are made up of wooden floors and, in some cases, steel beams and masonry arches. The numerical analysis evaluates first, a multiscale procedure to investigate the vulnerability of the whole aggregate and, then, the interaction of the individual SUs in the seismic conditions to more effectively predict the seismic behaviour of the investigated clustered structural units. Finally, structural retrofitting interventions are proposed to improve the expected performance level of the building under consideration, as well as its seismic dissipative capacity.