Mechanics-based fragility curves for Italian residential URM buildings

Abstract

Seismic risk assessment at the territorial level is now widely recognised as essential for countries with intense seismic activity, such as Italy. Academia is called to give its contribution in order to synergically deepen the knowledge about the various components of this risk, starting from the complex evaluation of vulnerability of the built heritage. In line with this, a mechanics-based seismic fragility model for Italian residential masonry buildings was developed and presented in this paper. This model is based on the classification of the building stock in macro-typologies, defined by age of construction and number of storeys, which being information available at national level, allow simulating damage scenarios and carrying out risk analyses on a territorial scale. The model is developed on the fragility of over 500 buildings, sampled according to national representativeness criteria and analysed through the Vulnus_4.0 software. The calculated fragility functions were extended on the basis of a reference model available in the literature, which provides generic fragilities for the EMS98 vulnerability classes, thus obtaining a fragility model defined on the five EMS98 damage states. Lastly, to assess the reliability of the proposed model, this was used to simulate damage scenarios due to the 2009 L’Aquila earthquake. Overall, the comparison between model results and observed damage showed a good fit, proving the model effectiveness.

Empirical fragility curves for Italian residential RC buildings

“…The proposed fragility model complies with the framework of the Italian national seismic risk platform (Borzi et al 2020b) and it was used, together with other vulnerability models (i.e. Borzi et al 2020a;Donà et al 2020;Lagomarsino et al 2020;Rosti et al 2020a;Zuccaro et al 2020), for national seismic risk assessment (NDPC 2018;Dolce et al 2019bDolce et al , 2020Masi et al 2020).…”

“…The presented empirical model was used, together with others (i.e. Borzi et al 2020a;Donà et al 2020;Lagomarsino et al 2020;Rosti et al 2020a;Zuccaro et al 2020) for assessing seismic risk in Italy (NDCP 2018; Dolce et al 2019bDolce et al , 2020Masi et al 2020), by using the IRMA platform.…”

Seismic risk assessment of residential buildings in Italy

“…In three cases the vulnerability model relies on an empirical approach, (Rosti et al 2020a,b;Zuccaro et al 2020). Two models adopt an analytical approach to develop fragility curves (Faravelli et al 2020;Donà et al 2020). Finally, a hybrid heuristic approach is employed in the sixth model (Lagomarsino et al 2020), as being based on the expert judgment implicitly encompassed in the EMS 98 scale (Grünthal 1998), but also calibrated on post earthquake damage data observed in Italy, available in DaDO platform.…”

A Multilevel Procedure at Urban Scale to Assess the Vulnerability and the Exposure of Residential Masonry Buildings: The Case Study of Pordenone, Northeast Italy

“…A reference model, derived from the conversion in PGA of the model of Lagomarsino and Cattari [36] through the law of correlation according to Margottini et al [79], was calibrated on the DS2-3 fragility curves. The following steps [54] were applied:…”

“…for each mechanical fragility curve, an optimal linear combination between two curves (DS2-3) of the macroseismic model was made, thanks to the genetic algorithm NSGA-II (i.e., Non-dominated Sorting Genetic Algorithm [54]), aimed at minimizing the absolute and relative errors;…”