Comparative assessment of empirical and mechanical approaches for the estimation of the seismic fragility of ordinary masonry buildings type of the inner central Italy

The assessment of the built heritage vulnerability is a needful task to mitigate the seismic risk. At this aim, fragility functions estimate the probability of exceedance of a structure at discrete levels of ground motion. The paper focuses on the estimation of seismic fragility of unreinforced masonry buildings typical of the inner Central Italy. Fragility assessments were performed for selected ordinary buildings representative of the urban fabric of the Central Italy, hit by the 2016 earthquake recently. The buildings' stock belongs to a macro-typology defined by structural features, easily available from visual inspections and geometric surveys. The structural performances of the buildings are assessed by means of empirical and numerical approaches, based on a large portfolio of information gathered after the 2016 earthquake swarm. Lastly, the fragility curves for the macro-typology have been derived referred to the attainment of four limit states of interest. A comparison between the obtained results in terms of probabilities of exceedance underlines the main advantages and limitations of each approach in the seismic vulnerability prediction on large scale applications.