Development of mechanics-based fragility curves for the Italian masonry school asset

This article presents the derivation of a fragility model for the Italian masonry school building asset, comprising 265 sets of fragility curves for as many building types, classified on the basis of few parameters: construction age, number of stories, plan area, and type of masonry (i.e. with regular or irregular pattern). The fragility assessment was carried out by means of parametric analyses, generating more than 7500 samples which were then analyzed through the mechanics-based procedure Vulnus. Sample fragilities were then linearly combined to obtain fragility curves consistent with the adopted taxonomy based on few parameters. A macroseismic-heuristic model from the literature was used to extend the fragility model to five damage states, according to the European Macroseismic Scale (EMS98). The proposed model was compared to empirical information in terms of observed damage on three existing schools and fragility curves recently derived by processing data of school damaged by the 2009 L'Aquila earthquake, showing a satisfactory agreement. In addition, a comparison with fragility sets for residential buildings was carried out. Both fragility models were developed with the same procedure, so as to point out differences between schools and ordinary buildings. Similar fragilities were observed for schools and residential buildings built before 1945, whereas for later periods, schools showed a higher fragility than the residential asset. Finally, seismic damage maps were developed at national scale showing the distribution of expected damage as a possible application of the derived model.