Seismic risk assessment of residential buildings by the Heuristic vulnerability model: influence of fragility curve models and inventory scale

Typological-observational methods still constitute one of the most commonly applied tools for evaluation of the seismic risk and vulnerability of the existing building stock. Their efficiency is mainly related to the effectiveness of the procedure for deriving fragility curves, and the reliability and completeness of the database that describes the building stock. This paper presents a comparison between the vulnerability and damage distribution assessment provided by fragility curves used in the Macroseismic and Heuristic methods, and a comparison of exposure evaluation methodologies according to two different approaches, namely a compartment- and a building-scale survey. An application to the case study of the residential building stock in the historic center of Alcamo, a town of 45,000 inhabitants in Western Sicily (Italy), shows the major reduction in fragility provided by recalibration of the masonry buildings’ ductility values that characterize the Heuristic method. Moreover, the efficiency of the compartment scale survey approach, based on the CARTIS typological-structural characterization method of ordinary buildings in urban areas, is underlined.