Comparison of seismic vulnerability for different classes of Italian reinforced concrete buildings

In this paper, empirical fragility curves were derived from post-earthquake damage data, to compare the seismic vulnerability of different classes of Italian reinforced concrete (RC) buildings. To identify the primary structural characteristics of the building stock, national seismic design codes were reviewed. The post-earthquake damage data, available on the online Da.D.O. platform, were collected following recent Italian seismic events and they provide information on typological and construction characteristics, as well as the damage observed at different structural components. Each dataset was critically analysed to ensure the reliability of the information used for subsequent statistical analyses. A global damage level was assigned to each surveyed building based on the damage detected at its vertical structure and infills. The ground shaking intensity was locally characterised through the Peak Ground Acceleration (PGA) values evaluated from the shakemaps provided by the Italian National Institute of Geophysics and Volcanology (INGV). Damage data were merged with exposure data to consider negative evidence of damage. Based on the typological information available from the exposure data, distinct classes of buildings were defined accounting for construction age and number of stories. Fragility functions were derived by statistically processing datasets via a Maximum Likelihood Estimation (MLE) procedure. The obtained fragility curves reflect the regulatory context of national seismic design codes. Age of construction and height confirmed to be parameters influencing the seismic vulnerability of RC buildings.