Seismic fragility and vulnerability curves for the Italian residential building stock

Abstract

In Italy, the recent regulatory and legislative developments relevant to the seismic risk mitigation of the existing building stock aim to propose tax deductions and simple but reliable approaches for the quantitative evaluation of the beneficial impacts of seismic retrofitting. Nevertheless, currently policy makers need tools and models able to assess the seismic risk and the cost/benefit of the strengthening interventions at regional/national level in order to plan future mitigation policies and be aware of the effectiveness of measures taken. To this aim, this article proposes a heuristic vulnerability model for large-scale applications. Starting from macroseismic approaches widely used in Europe, fragility and vulnerability curves for masonry and RC buildings are calibrated using a specific procedure based on the new Italian ‘guidelines for the seismic risk classification of constructions’ approved in January 2020, namely the so-called ‘Sisma Bonus.’ According to the construction material, building type and number of floors, the developed curves are defined in terms of vulnerability and height classes. The derived vulnerability model can be used in exposure models which rely on poor census data. Finally, it is compared with existing vulnerability models and the comparisons are analysed to demonstrate the effectiveness of the proposed model.