Seismic fragility modelling of unreinforced masonry buildings in Campania region

Past earthquakes have caused huge economic losses and considerable deaths, particularly as a consequence of heavy damage to historical masonry buildings. Despite the development of nation-wide vulnerability models for Italy, existing data sets show a significant inter-building variability across different regions, highlighting the chance of developing region-specific vulnerability models for seismic risk assessment. This paper presents a novel analytical fragility model for unreinforced masonry (URM) buildings located in Campania region (Southern Italy), where the built heritage was heavily damaged by the 1980 Irpinia earthquake. After that statistical data were collected from a national database, an automatic procedure for random generation of URM buildings representative of the regional building stock was developed to set up the building population at risk. Such a procedure allowed the generation of a significant number of structural models, accounting for different ages of construction, numbers of storeys, masonry types, and floor systems. Structural modelling of URM buildings was based on the equivalent frame approach using nonlinear fibre-based macro -elements. Numerical fragility was evaluated via nonlinear static procedures, a high-performance computing platform and conversion according to the MARS model. Fragility models were then successfully validated against damage observed after the 1980 Irpinia earthquake.