Empirical vulnerability curves for Italian residential buildings

This study focuses on the seismic vulnerability assessment of the Italian residential building stock, by taking advantage of post-earthquake damage data collected after past Italian seismic events of the period 1980-2009. Starting from the typological classification of the existing building stock, five vulnerability classes, three for masonry (i.e. A, B, C1) and two for reinforced concrete (i.e. C2 and D) buildings, are identified, grouping buildings exhibiting similar seismic behaviour. Seismic vulnerability is described by correlating empirically-derived damage index (DI) values and the peak ground acceleration, representing the selected ground motion intensity measure. To this aim, candidate functional forms are the lognormal and the exponential models. The accuracy of pre-selected functional forms to reproduce the observed seismic DI is demonstrated via graphical diagnostic and quantified in terms of a coefficient of accuracy. Parameters defining the proposed vulnerability functions are also provided. The results presented in this paper could be used in other regions having similar seismic hazard and built environment.