AUTHOR=Perelli Francesca Linda , De Gregorio Daniela , Montanino Andrea , Olivieri Carlo , Maddaloni Giuseppe , Iannuzzo Antonino 

TITLE=Energy-based modelling of in-plane fragility curves for the 2D ultimate capacity of Italian masonry buildings

JOURNAL=Frontiers in Built Environment

VOLUME=Volume 9 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/built-environment/articles/10.3389/fbuil.2023.1127523

DOI=10.3389/fbuil.2023.1127523

ISSN=2297-3362

ABSTRACT=The high seismic hazard of the Italian territory and the vulnerability of historic masonry heritage require the development of fragility curves that must be increasingly reliable and robustly correlated to exposure.
To date, national-scale seismic risk analyses mainly use empirical curves derived from the statistical analysis of damage induced by past events. These curves have shown good reliability, but they correlate only with a few typological-structural characteristics of the building, such as the number of floors, the vertical structure or the construction period. This paper aims to overcome this limitation with a hybrid approach that provides a better vulnerability characterisation.
The proposed hybrid strategy integrates the SAVE method and the piecewise rigid displacement (PRD) method. SAVE is an empirical approach based on the damage assessment due to past seismic events used to identify a seismic behavior of structures, while the PRD method is a numerical approach that solves the boundary value problem for normal, rigid, no-tension material. It can model different structural typologies and provides the value of the horizontal static multiplier that drives the masonry construction to collapse.
An extended numerical campaign is carried out considering a sample of 750 masonry buildings extracted from a typological database through a Monte Carlo simulation. Referring to a single construction, first, a PRD analysis is conducted to define its seismic capacity, paying special attention to modelling construction details. After that, the SAVE method is used to classify the construction in a specific seismic vulnerability class, from A to C, with decreasing vulnerability.
All the buildings belonging to the same class are collected, and three fragility curves representative of the collapse state (one for each class) are derived and validated against analytical ones commonly adopted in the Literature. The integrated methodology shows a good agreement with simulations, confirming the viability of the proposed hybrid methodology for evaluating the seismic risk for unreinforced masonry buildings. Because of its computational fast-solving and easy modelling of the structural characteristics, the proposed hybrid approach represents an accurate and robust approach for the large-scale assessment of masonry buildings, providing an effective strategy to plan mitigation and rehabilitation interventions.