Browsing by Author "Palazzi Chiara, Nuria"

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    Kinematic limit analysis of Basilica del Salvador, a significant example of the neo-gothic architecture in Santiago, Chile
    Palazzi Chiara, Nuria; Rovero, Luisa; Tonietti, Hugo; Llera Martin, Juan Carlos de la; Sandoval Mandujano, Cristián
    The Basilica del Salvador, located in Santiago city, is one of the most significant examples of the Chilean Neogothic architecture. Its current state of damage shows several local collapses caused by the March 3rd, 1985 central Chile earthquake, and the February 27th, 2010 Maule earthquake. As part of an ongoing research, this paper investigates the seismic behaviour of the church through the kinematic limit analyses. For this purpose, the main collapse mechanisms have been identified and analyzed. The results show that the seismic response is unsatisfactory and shows the inadequacy of the seismic performance of this constructional typology in a highly seismic context, due to the extremely slenderness of the structural elements and to the absence of box-behaviour, making it particularly sensitive to earthquake loading. It should be noted that these preliminary results are part of an ongoing research about the seismic retrofit of Basilica del Salvador.
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    Multi-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.
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    Preliminary Assessment on Seismic Vulnerability of Masonry Churches in Central Chile
    (2019) Palazzi Chiara, Nuria; Llera Martin, Juan Carlos de la; Sandoval Mandujano, Cristian
    The 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.
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    Seismic 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 la
    An 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.
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    Seismic 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 Ingeniería
    The 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).
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    Seismic Vulnerability Assessment of a 17th Century Colonial Adobe Church in the Central Valley of Chile
    (2020) Palazzi Chiara, Nuria; Misseri, Giulia; Rovero, Luisa; Llera Martin, Juan Carlos de la
    This paper focuses on the seismic vulnerability assessment of the San Judas Tadeo´s church in Malloa (Chile), an iconic example of Colonial Chilean architecture. This small adobe structure is a single-nave building consisting of the nave, a bell-tower located in the façade, two external wooden galleries and a number of additional units such as the sacristy, chapel, and two services areas. The Church has survived several strong earthquakes larger than Mw>8. Besides, after the February 27th, 2010 Maule event it showed remarkable resilience due to the implementation of traditional timber retrofits inserted in the earthen walls. The use of traditional wooden devices such as bond beams, corner keys, and wooden gables, proved to be effective solutions against strong earthquakes. Therefore, this church appears as a relevant case of the use of seismic resistant constructive techniques of the17th century colonial architecture and the study of its seismic behaviour holds great interest and relevance. Aimed to assess the seismic vulnerabilityof the monument, a complete study of the church was carried out using a multi-level approach comprising historical research, in situ surveys, crack pattern analysis, physical and mechanical characterization of materials, and local and global structural analyses. In particular, the linear and incremental kinematic approaches with limit analysis have been employed with the aim of interpreting the local mechanisms activated during the 2010 Maule earthquake. In these models, the effect of friction of masonry-to-masonry and timber-to-masonry interfaces, as well as the limited tensile strength of masonry, was all considered. This study results prove the general validity in the field of timberseismic retrofitting of unreinforced adobe buildings
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