Damage inspection in churches : the Canterbury Earthquake (New Zealand) experience (original) (raw)
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Damage and performance evaluation of masonry churches in the 2009 L’Aquila earthquake
Engineering Failure Analysis, 2013
The seismic behaviour of masonry churches damaged during the 2009 L'Aquila earthquake is studied in this paper. Four important basilicas are considered in order to derive general conclusions from the damage assessment and the performance analysis. As a general result of the comparison between the post-earthquake survey activity and the structural analyses the possibility of evaluating the seismic safety of churches, and therefore of avoiding destructive damage by means of the design and application of appropriate retrofit interventions, is confirmed.
Journal of Earthquake Engineering, 2012
The Canterbury Region of New Zealand experienced an extensive earthquake sequence during 2010–2011, with two particularly severe events being on September 4, 2010 and February 22, 2011. The present work entails a statistical analysis of the data collected for 112 churches in the affected region, including in situ damage observed by the authors and the structural assessment classification assigned by local authorities. The seismic performance of these churches is discussed and compared with both the structural classifications used in Italy, where a specific survey form for churches is used, and with the building damage classifications assigned by the local authorities.
Development of parametric seismic fragility curves for historical churches
Bulletin of Earthquake Engineering
For both spiritual and cultural reasons, churches are an essential part of the historical heritage of several countries worldwide, including Europe, Americas and Australasia. The extreme damage that occurred during the 2016–2017 Central Italy seismic swarm highlighted once again the noteworthy seismic vulnerability of unreinforced masonry churches, which exhibited several collapses and caused uncountable losses to the Italian artistic heritage. The seismic performance of 158 affected buildings was analyzed in the aftermath of the main shocks. The failure modes activated by the earthquakes were identified making reference to the local mechanisms currently considered in Italy for post-seismic assessment of churches. The structural damage of the investigated buildings, related to 21 mechanisms rather than to an overall global response, was explained resorting to empirical statistical procedures taking into account ground motion intensity and structural details that can worsen or improv...
The damage assessment of monumental buildings after numerous seismic events in different countries has systematically highlighted the vulnerability of monumental structures, in particular churches, and the critical importance of reducing their risk from an economic, cultural and social point of view. This evidence has been highlighted, once again, by the Canterbury earthquake sequence, that dramatically affected New Zealand in 2010-2011. Within this context, detailed analysis is reported of the earthquake-induced damage to a stock of 48 unreinforced masonry (URM) churches located in the Canterbury Region and the seismic vulnerability analysis of a wider stock of 293 URM churches located all around New Zealand. The final aim of the study was the collection of meaningful data and evidence to support mitigation strategies and policies for reducing the seismic risk for churches. To support this aim, new tools and forms were developed that are specifically oriented to facilitate analysis of the features of New Zealand churches. The computation of a new damage grade is proposed, assessed as a proper combination of the damage level to each macroelement, as a step towards the definition of a New Zealand specific damage survey form and the preliminary derivation of empirical fragility curves. For the vulnerability analysis several indicators were selected, which are related to easily detectable structural details and geometric dimensions. The collection of such data for the larger set of churches (293) provided an overview of structural features of this class in New Zealand and constitutes a useful basis for evaluating the potential impact of future seismic events.
2012
Unreinforced masonry churches are particularly vulnerable to earthquakes because they are often deteriorated and damaged, they were built with comparatively low strength materials, they are heavy, and the connections between the various structural components are often insufficient to resist loads generated during earthquakes. A simplified method for seismic assessment of large span masonry churches is presented and data from 44 churches located in Italy, Portugal and Spain are used to provide lower bound limits for different simplified geometrical indexes. Subsequently, the proposed thresholds are validated with data from the 2010-2011 Canterbury earthquakes, including 48 clay brick and stone unreinforced masonry churches. Finally, data collected for 40 unreinforced masonry churches in Wellington and Dunedin are used to identify churches in these cities requiring priority detailed seismic evaluation.
Seismic Vulnerability Assessment for Masonry Churches: An Overview on Existing Methodologies
MDPI, 2021
The present manuscript deals with the seismic vulnerability assessment of existing masonry churches, which is a fundamental process for risk and consequent prioritization analyses, as well as application of effective retrofitting strategies. In the past, different approaches with various levels of accuracy and application ranges have been developed to assess the vulnerability to damage of such structures in case of seismic events. Based on the classification provided in the Italian Guidelines for the Cultural Heritage, in this paper a review of seismic vulnerability assessment method-ologies for existing masonry churches is presented. The main goal of the current study is to provide a critical comparative overview about these procedures, highlighting the main issues related to the application of each detail level. Moreover, particular attention is focused on the applications present in literature, allowing for the definition of a potential systematic procedure for smart management p...
Damage Assessment of Historical Masonry Churches Subjected to Moderate Intensity Seismic Shaking
Sustainibility, 2021
An earthquake of magnitude 4.3 MW struck Cosenza (Calabria region, South Italy) and its immediate area on 24 February 2020. Although no damage was reported to ordinary masonry buildings, the ancient masonry churches suffered widespread damage. The herein article presents an analysis of the failures suffered by monumental buildings (e.g., churches) following a moderate seismic action. The contribution is based on the in situ damage observation of 14 churches, with a dating ranging from the 12th to 20th century. The study consists of a first phase, in which the different damage modes are identified, describing their causes and effects, and a second phase that correlates the damage detected to the main parameters that influence the seismic response of the churches (geometric characteristics, boundary condition, masonry and floor organization, past interventions, etc.), regardless of the state of conservation that was discrete for all buildings before the telluric event. From the rapid visual survey, the “weight” of each seismic parameter on the type of damage detected was then established. The past “retrofitting” interventions were decisive in the response of the ancient structure, with particular regard to those that made an aggravation of seismic mass and an increase in stiffness.
Journal of Earthquake Engineering, 2016
The 2010-2011 Canterbury earthquake sequence caused extensive damage to unreinforced masonry churches. A sample of 80 affected buildings was analysed and their performance statistically interpreted. Structural behaviour is described in terms of mechanisms affecting the so-called macro-elements, and damage probability matrices are computed. Regression models correlating mean damage level against macroseismic intensity are also developed for all observed mechanisms, improving the initial simple-linear formulations through use of multiplelinear regressions accounting for vulnerability modifiers, whose influence is evaluated via statistical procedures. Results presented herein will support the future development of predictive tools for decision-makers, also contributing to seismic vulnerability mitigation at a territorial scale.
2014
The 2009 seismic event occurred in L’Aquila (Italy) caused many losses, with severe damage of the whole monumental heritage of the Abruzzi Region and in particular for churches. The current paper reports the main results of a research campaign carried out by the authors after the 2009 L’Aquila earthquake. This has been focused on the religious buildings belonging to the Sulmona-Valva diocese, a territorial area located at the boundary of L’Aquila district, which undertook slight-medium damages during the seismic events. In a first stage, a detailed investigation, carried out on the basis of observations on a population of twenty-six three naves churches, is presented aiming to define local and global levels of damage according to the criteria introduced by the EMS-98 macro-seismic scale. Therefore, the collected data-set is managed from the statistical point of view in order to obtain Damage Probability Matrices (DPMs). Then, a predictive model based on the identification of the mai...
Seismic damage and fragility assessment of ancient masonry churches located in central Chile
Bulletin of Earthquake Engineering, 2020
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.