Browsing by Author "Palazzi Chiara, Nuria"
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- ItemMulti-vulnerability analysis for seismic risk management in historic city centres: an application to the historic city centre of La Serena, Chile(2023) Baquedano Juliá, Pilar; Ferreira, Tiago Miguel; Arriagada Luco, Camilo; Sandoval Mandujano, Cristián; Palazzi Chiara, Nuria; Oliveira, Daniel V.A comprehensive understanding of the elements at risk, through the identification of the main hazards, level of exposure and different dimensions of the vulnerability of the communities, is an essential step toward the definition and adoption of more effective risk reduction strategies. Historic urban centres have received special attention in the assessment of damage and physical vulnerability to earthquakes, but it is well known that vulnerability also depends on the social and demographic characteristics of communities. This paper discusses the application of a holistic approach aimed at assessing the seismic vulnerability of historic urban centres by considering their physical and social dimensions. Two index-based methodologies are presented, and the data are analyzed using the CENSUS block as the unit of study, which is scarcely present in the literature. The results of both indices are crossed through a matrix, which allows the classification of the blocks in five levels of priority and are mapped using a Geographic Information System tool. The Historic city centre of La Serena, one of the oldest in Chile, was selected as a case study. This historic city centre still preserves historic buildings of raw earth of diverse architectural typologies widely distributed throughout the country, which makes it relevant, not only by itself but as a model that can be replicated and extrapolated to other historic centres of similar constructive characteristics.
- ItemPreliminary Assessment on Seismic Vulnerability of Masonry Churches in Central Chile(2019) Palazzi Chiara, Nuria; Llera Martin, Juan Carlos de la; Sandoval Mandujano, CristianThe 2010 Maule Chile earthquake (Mw 8.8) caused extensive structural damage to the built heritage. In particular, the poor seismic performance of a set of unreinforced masonry (URM) churches highlighted the need to implement protective and safety strategies in order to preserve these buildings which exhibit unique constructive and typological features, as a result of a combination of Chilean and European construction cultures. The peculiarity of this heritage and the high seismic hazard of Chilean territory have motivated the present study which aims to apply systematic procedures to assess the seismic vulnerability of these buildings. This article is of archival nature and presents a complete database generated from the geometrical, constructive, and structural characteristics of a representative stock of 106 churches located in central Chile, with the goal of proposing fragility curves to be used in seismic risk assessment. Considering variables related with geometrical, architectonic, and stylistic features, as well as damage levels for the 2010 Maule earthquake, this church sample is classified into three homogenous groups: colonial, neo-classic, and neo-gothic. Moreover, a preliminary qualitative assessment of the seismic capacity of these structures is provided using a survey and analysis of geometric indices for each of the three selected groups.
- ItemSeismic damage and fragility assessment of ancient masonry churches located in central Chile(2020) Palazzi Chiara, Nuria; Favier, Philomène; Rovero, Luisa; Sandoval Mandujano, Cristián; Llera Martin, Juan Carlos de laAn assessment of damage and seismic fragility of historical unreinforced masonry churches located in Chile’s central valley was carried out employing the results of a field survey of 106 ancient churches, after the 2010 Maule earthquake. The observed damage was correlated with recurrent failure mechanisms of unreinforced masonry structures, by taking into account 22 local mechanisms involving macro-elements on these churches. The average damage level suffered by each church was computed considering the global and local behaviors of the structures through a damage index computed as a weighted mean of the levels of damage observed for each mechanism. The results of this damage index method are used to obtain Probability Mass Functions and suitable probabilistic tools are used to propose Empirical Fragility Curves (EFCs) for these structures. The EFCs are directly usable by stakeholders involved in risk assessment aimed to the prioritization of possible future damage mitigation strategies and other decision making processes relative to this historical heritage.
- ItemSeismic fragility assessment of unreinforced masonry churches of central Chile.(2019) Palazzi Chiara, Nuria; Llera Martin, Juan Carlos de la; Rovero, Luisa; Pontificia Universidad Católica de Chile. Escuela de IngenieríaThe present thesis focuses on the seismic fragility assessment of unreinforced masonry (URM) churches in central Chile. The intrinsic value of this built heritage is due to its original features, synthesis of local and European architectural cultures. Due to the structural weaknesses of URM monuments, Chile‘s high seismic hazard, the absence of design standards and guidelines, and the ineffective performance of recently implemented retrofits, this built heritage is at-risk. For these reasons, the broad scope of this study is to document, for the first time, an essential part of the heritage asset of Chile, and to highlight principal vulnerabilities through a proper safety assessment framework, with the aim to promote conservation policies compatible with heritage identity and meeting new safety requirements. Historical, typological and technological features of the selected churches, consisting of 106 churches, are outlined and consistent categories are formed. Churches of each class share stylistic and technological characteristics, but also and more importantly, the same structural weaknesses. Within this framework, two scales are adopted to investigate the seismic performance of these monuments: territorial and building. At territorial-scale, the selected 106 churches are organized in a database that collects essential information for fragility assessment and damage forecasting (e.g. expected 2010 Maule PGA, architectural, typological, and material parameters). As a result, the main variables that control the seismic fragility of these structures were determined. The main outcome obtained downstream from this survey is related the damage suffered by the entire stock following the 2010 (8.8Mw) Maule earthquake. The matrix of plots for the frequency distributions of the selected variables and damage level frequency diagrams enabled the identification of the following three homogeneous classes. These are: Colonial (CL), Neo-classical & Variant (NC&V) and Neo-gothic (NG). Probability Mass Functions (PMFs)and Empirical Fragility Curves (EFCs) have been obtained using validated models such as a lognormal distribution fitted by least squares, and a generalized linear model function fitted by maximum likelihood estimation. At building-scale, three case studies representative of fragility classes are identified. These churches are: San Francisco in Santiago, San Judas in Malloa, and San Salvador in Santiago. A methodology to assess the seismic performance of these URM structures is provided, and the seismic response and risk quantified. Finally, a new procedure is proposed to evaluate arbitrary structural retrofit interventions in view of more general ICOMOS principles. For each intervention, a conformity level in terms of alignment with conservation principles has been assessed. This methodology has been applied to evaluate the retrofit interventions proposed or implemented to reinforce the three selected case studies. This thesis provides useful predictive tools for seismic risk reduction plans of churches, which is directly usable as a framework to be employed by stakeholders and safety related decisionmakers. Moreover, the main findings can be exported to all those contexts in which European architectural revivalisms have influenced local building techniques (e.g. Central and Southern America).
- ItemSeismic vulnerability of timber-reinforced earthen structures through standard and non-standard limit analysis(2020) Misseri, G.; Palazzi Chiara, Nuria; Rovero, L.