Damage, casualty, and loss scenarios for New Zealand’s North Island churches (original) (raw)
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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.
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.
Damage and vulnerability analysis of URM churches after the Canterbury earthquake sequence 2010-2011
2015
The Canterbury earthquake sequence, in 2010-2011, has highlighted once again the vulnerability of monumental structures, in particular churches, and the importance of reducing their risk from an economic, cultural and social point of view. Within this context, detailed analysis is reported of the earthquake-induced damage to a stock of 48 unreinforced masonry churches located in the Canterbury Region and the vulnerability analysis of a wider stock of 293 churches located all around New Zealand. New tools were developed for the assessment 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. Several vulnerability 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) constitutes a useful basis...
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.
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.
Frontiers in Built Environment
In this paper, seismic vulnerability and risk assessment of two samples of churches, located in Teramo and Ischia island (Naples gulf), both affected by the most recent earthquakes that occurred in Italy, are presented. To this aim, we applied a simplified method particularly suitable for seismic evaluations at a territorial scale, providing a global resulting score to be compared among the cases analyzed. The data obtained allowed us to provide vulnerability maps and a seismic risk index for all the considered churches. In addition, the calculated indexes permit a preliminary health state evaluation of the inspected churches, for ranking the priorities and planning additional in-depth evaluations.
Vulnerability assessment of churches under earthquake hazard
Vernacular Heritage and Earthen Architecture, 2013
The development of a framework for the quantification of the seismic vulnerability of churches is presented. Given the advantages of having different areas of expertise contributing for the assessment of vulnerability, the proposed framework involves a multidisciplinary approach for the definition of the vulnerability of churches. The general scope and the conceptual definition of the proposed framework are discussed and it is established that vulnerability assessment must be carried out with respect to three fundamental components: the building, the collections and the building surroundings. Implementation details of the framework are then presented for the specific case of church heritage under seismic hazard. The applicability of the vulnerability assessment approach is illustrated using real case scenarios.
Damage inspection in churches : the Canterbury Earthquake (New Zealand) experience
Cultural Help 2014 Cultural Heritage and Loss Prevention, 2014
The Canterbury Region of New Zealand experienced an extensive earthquake sequence during 2010-2011, with two particularly sever events being on September 4, 2010 and February 22, 2011. The present work entails a statistical analysis of the data for 112 churches in the affected region, including in situ damage observed by the authors and the structural assessment classification assigned by the local authorities, allowing for the discussion of the seismic performance of these churches separated in three main typologies: i) stone masonry; ii) clay brick masonry churches; iii) timber churches. A simplified method of assessment of large span masonry structures, which had already been applied to a database of 44 monuments in Italy, Portugal and Spain, was applied with the objective of validating the proposed thresholds. A set of fragility curves, with the objective of estimating damage as a function of the peak ground acceleration, is also provided. It was concluded that the timber churches had an excellent seismic performance, registering only non-structural damage, while the stone and clay brick churches clearly performed unsatisfactorily. The simplified method, which includes three separated indexes, presented very good results for one index (plan area ratio), and acceptable results for the other two (weight ratio and base shear ratio).
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...
Seismic vulnerability assessment of churches at regional scale after the 2009 L'Aquila earthquake
International Journal of Masonry Research and Innovation, 2019
The extension of damage on churches observed after strong earthquakes stresses the need to define suitable speedy methods for the assessment of the main sources of structural fragility for these constructions. This paper presents a methodology for seismic vulnerability assessment of churches based on a damage reconnaissance activity carried out after the 2009 L'Aquila earthquake on a population of 64 churches. Firstly, the post-earthquake evaluation of damage is described aiming at identifying recurrent damage mechanisms. It has been observed that the occurred damage This paper is a revised and expanded version of a paper entitled 'Seismic vulnerability assessment of churches at regional scale after the 2009 L'Aquila earthquake', presented at the Workshop MCM2016: Mechanics of Masonry Constructions, Cassino, Italy, 4 July 4 2016.