PSI - Issue 44

Giovanni Tondo et al. / Procedia Structural Integrity 44 (2023) 243–250

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Giovanni Tondo et al. / Structural Integrity Procedia 00 (2022) 000–000

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1. Introduction

Seismic risk assessment allows to estimate the consequences of an earthquake for a specific building or a region, therefore it is useful for planning risk mitigation measurements both at regional and local level. The buildings’ vulnerability is one of the main parameters affecting the seismic risk, in particular for masonry buildings which are typically not designed according to seismic code provisions (Xofi et al. 2022). According to the Italian National Institute of Statistics, about 57% of the Italian residential buildings are made up of masonry and were mainly built between 1918 and 2006 (ISTAT, 2011). Italy is a country characterized by intense seismic activity, as demonstrated by the damage caused by several earthquakes occurred over the years (Kawashima et al., (2010), Fiorentino et al., (2018), Mucciarelli et al., 2014)). It is well known that the seismic structural response of masonry buildings depends on several aspects, such as the quality of the masonry, the floor stiffness or the geometrical irregularity. With respect to the 2009 L’Aquila Earthquake, Augienti et al. (2010) pointed out that the characteristics that impacted the most the seismic vulnerability of masonry structures were the poor quality of the walls and the presence of in-plan irregularities. In this context, it is worth noting that the masonry quality can significantly vary with and within regions and provinces (Tocchi et al, 2021). The latest events that shook central Italy (i.e., Amatrice 2016 and L’Emilia 2012 Earthquake) continued to demonstrate the seismic vulnerability of masonry building and the need for the definition of large scale seismic risk endeavors in order to effective planning mitigation measurements and to help public and private stakeholders in prioritizing limited economic resources. In this sense, the use of simplified approaches to predict the seismic vulnerability of a large number of buildings becomes practically mandatory. Among the methodologies that can be used for an expeditious assessment of the seismic vulnerability, those based on vulnerability indices, have proved, in the recent decades, to be effective in the study of large building stocks (Athmani et al. 2015). In particular, the methods based on Rapid Visual Screening (RVS) can be used for preliminary assessment, to identify the buildings with higher associated seismic risk within the same area. RVS methods do not require detailed calculations, but their goal is rather to identify buildings that require more advanced modelling and analysis (Ruggieri et al., 2020). In light of the above, the objective of this work is to evaluate the effectiveness of the main RVS methodologies available in the literature, when applied to masonry buildings, using the results of non-linear static analyses carried out on a building portfolio representative of Italian masonry buildings. 2. Definition of building portfolio In order to obtain a masonry building portfolio representative of the residential Italian building stock, the data collected in the Da.D.O. ( Database di Danno Osservato , Database of Observed Damage) platform and ISTAT (2011) was used, as described in the next sections. 2.1. Da.d.o. platform In the past, post-earthquake datasets were collected in different databases, causing non-homogeneity of information and making it not effectively usable. Since 2014, the Italian Department of Civil Protection has started the development of a comprehensive database, with the support of the Eucentre Foundation, creating an IT platform aimed at collecting, cataloging, and comparing data related to building and structural characteristics, as well as to seismic damage. The post-earthquake information came from on-site inspections carried out following seismic events occurred from 1976 onwards. Starting from 1996/97 the post-earthquake inspections were carried out using a specific form (AeDES) (Baggio et al., 2007), which allowed to harmonize the geometrical, structural and damage data collected for each building (Colozza et al., 2000). Focusing on 2009 L’Aquila Earthquake, the collected data concerns 74049 buildings, most of them (85%) with a residential use. Regarding the type of structures, 67% consist of masonry buildings; 17% represent reinforced concrete buildings, and 16% mixed or undefined structural typologies (Scala et al., 2022). In this study, only residential masonry buildings are considered, and the developed statistics are based on the data collected following thee 2009 L’Aquila Earthquake.