Farming and urban regions are impacted by earthquake disasters in different ways, and feature a range of often different recovery requirements. In New Zealand, and elsewhere, most earthquake impact and recovery research is urban focused. This creates a research deficit that can lead to the application of well-researched urban recovery strategies in rural areas to suboptimal effect. To begin to reduce this deficit, in-depth case studies of the earthquake impacts and recovery of three New Zealand farms severely impacted by the 14th November 2016, M7.8 Hurunui-Kaikōura earthquake were conducted. The initial earthquake, its aftershocks and coseismic hazards (e.g., landslides, liquefaction, surface rupture) affected much of North Canterbury, Marlborough and the Wellington area. The three case study farms were chosen to broadly represent the main types of farming and topography in the Hurunui District in North Canterbury. The farms were directly and indirectly impacted by earthquakes and related hazards. On-farm infrastructure (e.g., woolsheds, homesteads) and essential services (e.g., water, power), frequently sourced from distributed networks, were severely impacted. The earthquake occurred after two years of regional drought had already stressed farm systems and farmers to restructuring or breaking point. Cascading interlinked hazards stemming from the earthquakes and coseismic hazards continued to disrupt earthquake recovery over a year after the initial earthquake. Semi-structured interviews with the farmers were conducted nine and fourteen months after the initial earthquake to capture the timeline of on-going impacts and recovery. Analysis of both geological hazard data and interview data resulted in the identification of key factors influencing farm level earthquake impact and recovery. These include pre-existing conditions (e.g., drought); farm-specific variations in recovery timelines; and resilience strategies for farm recovery resources. The earthquake recovery process presented all three farms with opportunities to change their business plans and adapt to mitigate on-going and future risk.
Knowing how to rapidly rebuild disaster-damaged infrastructure, while deciding appropriate recovery strategies and catering for future investment is a matter of core interest to government decision makers, utility providers, and business sectors. The purpose of this research is to explore the effects of decisions and outcomes for physical reconstruction on the overall recovery process of horizontal infrastructure in New Zealand using the Canterbury and Kaikoura earthquakes as cases. A mixed approach including a systematic review, questionnaire survey and semi-structured interviews is used to capture perspectives of those involved in reconstruction process and gain insights into the effect of critical elements on infrastructure downtime. Findings from this research will contribute towards advancements of a systems dynamics model considering critical decision-making variables across phases of the reconstruction process to assess how these variables affect the rebuild process and the corresponding downtime. This project will improve the ability to explore alternative resilience improvement pathways and test the efficacy of alternative means for facilitating a faster and better reconstruction process.
We measure the longer-term effect of a major earthquake on the local economy, using night-time light intensity measured from space, and investigate whether insurance claim payments for damaged residential property affected the local recovery process. We focus on the destructive Christchurch earthquake of 2011 as our case study. In this event more than 95% of residential housing units were covered by insurance, but insurance payments were staggered over 5 years, enabling us to identify their local impact. We find that night-time luminosity can capture the process of recovery and describe the recovery’s determinants. We also find that insurance payments contributed significantly to the process of economic recovery after the earthquake, but delayed payments were less affective and cash settlement of claims were more affective in contributing to local recovery than insurance-managed rebuilding.
Natural catastrophes are increasing worldwide. They are becoming more frequent but also more severe and impactful on our built environment leading to extensive damage and losses. Earthquake events account for the smallest part of natural events; nevertheless seismic damage led to the most fatalities and significant losses over the period 1981-2016 (Munich Re). Damage prediction is helpful for emergency management and the development of earthquake risk mitigation projects. Recent design efforts focused on the application of performance-based design engineering where damage estimation methodologies use fragility and vulnerability functions. However, the approach does not explicitly specify the essential criteria leading to economic losses. There is thus a need for an improved methodology that finds the critical building elements related to significant losses. The here presented methodology uses data science techniques to identify key building features that contribute to the bulk of losses. It uses empirical data collected on site during earthquake reconnaissance mission to train a machine learning model that can further be used for the estimation of building damage post-earthquake. The first model is developed for Christchurch. Empirical building damage data from the 2010-2011 earthquake events is analysed to find the building features that contributed the most to damage. Once processed, the data is used to train a machine-learning model that can be applied to estimate losses in future earthquake events.
<b>In the late 1960s the Wellington City Council surveyed all the commercial buildings in the city and marked nearly 200 as earthquake prone. The owners were given 15 years to either strengthen or demolish their buildings. The end result was mass demolition throughout the seventies and eighties.¹ Prompted by the Christchurch earthquakes, once again the council has published a list of over 630 earthquake prone buildings that need to be strengthened or demolished by 2030.²Of these earthquake prone buildings, the majority were built between 1880 and 1930, with 125 buildings appearing on the Wellington City Council Heritage Building List.³ This list accounts for a significant proportion of character buildings in the city. There is a danger that the aesthetic integrity of our city will be further damaged due to the urgent need to strengthen these buildings. Many of the building owners are resistant because of the high cost. By adapting these buildings to house co-workspaces, we can gain more than just the retention of the building’s heritage. The seismic upgrade provides the opportunity for the office space to be redesigned to suit changes in the ways we work. Through a design-based research approach this thesis proposes a framework that clarifies the process of adapting Wellington’s earthquake prone heritage buildings to accommodate co-working. This framework deals with the key concepts of program, structure and heritage. The framework is tested on one of Wellington’s earthquake prone heritage buildings, the Wellington Working Men’s Club, in order to demonstrate what can be gained from this strengthening process. ¹ Reid, J., “Hometown Boomtown,” in NZ On Screen (Wellington, 1983).</b>
² Wellington City Council, List of Earthquake Prone Buildings as at 06/03/2017. (Wellington: Absolutely Positively Wellington. 2017).
³ ibid.
Very little research exists on total house seismic performance. This testing programme provides stiffness and response data for five houses of varying ages including contributions of non-structural elements. These light timber framed houses in Christchurch, New Zealand had minor earthquake damage from the 2011 earthquakes and were lateral load tested on site to determine their strength and stiffness, and preliminary damage thresholds. Dynamic characteristics were also investigated. Various loading schemes were utilised including quasi-static loading above the foundation, unidirectional loading through the floor diaphragm, cyclic quasi-static loading and snapback tests. Dynamic analysis on two houses provided the seismic safety levels of post-quake houses with respect to local hazard levels. Compared with New Zealand Building Standards all the tested houses had an excess of strength, damage is a significant consideration in earthquake resilience and was observed in all of the houses. A full size house laboratory test is proposed.
By closely examining the performance of a 22-storey steel framed building in Christchurch subject to various earthquakes over the past seven years, it is shown that a number of lessons can be learnt regarding the cost-effective consideration of non-structural elements. The first point in this work is that non-structural elements significantly affected the costs associated with repairing steel eccentrically braced frame (EBF) links. The decommissioning or rerouting of non-structural elements in the vicinity of damaged links in the case study building attributed to approximately half the total cost of their repair. Such costs could be significantly reduced if the original positioning of non-structural elements took account of the potential need to repair the EBF links. The second point highlighted is the role that pre-cast cladding apparently played on the distribution and type of damage in the building. Loss estimates obtained following the FEMA P-58 framework vary considerably when cladding is or isnt modelled, both because of changes to drift demands up the height of the building and because certain types of subsequent damage are likely to be cheaper to repair than others. Finally, costly repairs to non-structural partition walls were required not only after the moment magnitude 7.1 earthquake in 2010 but also in multiple aftershocks in the years that followed. Repair costs associated with aftershock events exceeded those from the main event, emphasizing the need to consider aftershocks within modern performance-based earthquake engineering and also the opportunity that exists to make more cost-effective repair strategies following damaging earthquakes.
Introduction This poster presents the inferred initial performance and recovery of the water supply network of Christchurch following the 22 February 2011 Mw 6.2 earthquake. Results are presented in a geospatial and temporal fashion. This work strengthens the current understanding of the restoration of such a system after a disaster and quantifies the losses caused by this earthquake in respect with the Christchurch community. Figure 1 presents the topology of the water supply network as well as the spatial distribution of the buildings and their use.
Reinforced concrete buildings that satisfied modern seismic design criteria generally behaved as expected during the recent Canterbury and Kaikoura earthquakes in New Zealand, forming plastic hinges in intended locations. While this meant that life-safety performance objectives were met, widespread demolition and heavy economic losses took place in the aftermath of the earthquakes.The Christchurch central business district was particularly hard hit, with over 60% of the multistorey reinforced concrete buildings being demolished. A lack of knowledge on the post-earthquake residual capacity of reinforced concrete buildings was a contributing factor to the mass demolition.Many aspects related to the assessment of earthquake-damaged reinforced concrete buildings require further research. This thesis focusses on improving the state of knowledge on the post earthquakeresidual capacity and reparability of moderately damaged plastic hinges, with an emphasis on plastic hinges typical of modern moment frame structures. The repair method focussed on is epoxy injection of cracks and patching of spalled concrete. A targeted test program on seventeen nominally identical large-scale ductile reinforced concrete beams, three of which were repaired by epoxy injection following initial damaging loadings, was conducted to support these objectives. Test variables included the loading protocol, the loading rate, and the level of restraint to axial elongation.The information that can be gleaned from post-earthquake damage surveys is investigated. It is shown that residual crack widths are dependent on residual deformations, and are not necessarily indicative of the maximum rotation demands or the plastic hinge residual capacity. The implications of various other types of damage typical of beam and column plastic hinges are also discussed.Experimental data are used to demonstrate that the strength and deformation capacity of plastic hinges with modern seismic detailing are often unreduced as a result of moderate earthquake induced damage, albeit with certain exceptions. Special attention is given to the effects of prior yielding of the longitudinal reinforcement, accounting for the low-cycle fatigue and strain ageing phenomena. A material-level testing program on the low-cycle fatigue behaviour of grade 300E reinforcing steel was conducted to supplement the data available in the literature.A reduction in stiffness, relative to the initial secant stiffness to yield, occurs due to moderate plastic hinging damage. This reduction in stiffness is shown to be correlated with the ductility demand,and a proposed model gives a conservative lower-bound estimate of the residual stiffness following an arbitrary earthquake-type loading. Repair by epoxy injection is shown to be effective in restoring the majority of stiffness to plastic hinges in beams. Epoxy injection is also shown to have implications for the residual strength and elongation characteristics of repaired plastic hinges.
Natural hazard reviews reveal increases in disaster impacts nowhere more pronounced than in coastal settlements. Despite efforts to enhance hazard resilience, the common trend remains to keep producing disaster prone places. This paper explicitly explores hazard versus multi-hazard concepts to illustrate how different conceptualizations can enhance or reduce settlement resilience. Understandings gained were combined with onthe-ground lessons from earthquake and flooding experiences to develop of a novel ‘first cut’ approach for analyzing key multi-hazard interconnections, and to evaluate resilience enhancing opportunities. Traditional disaster resilience efforts often consider different hazard types discretely. However, recent events in Christchurch, a New Zealand city that is part of the 100 Resilient Cities network, highlight the need to analyze the interrelated nature of different hazards, especially for enhancing lifelines system resilience. Our overview of the Christchurch case study demonstrates that seismic, hydrological, shallow-earth, and coastal hazards can be fundamentally interconnected, with catastrophic results where such interconnections go unrecognized. In response, we have begun to develop a simple approach for use by different stakeholders to support resilience planning, pre and post disaster, by: drawing attention to natural and built environment multi-hazard links in general; illustrating a ‘first cut’ tool for uncovering earthquake-flooding multi-hazard links in particular; and providing a basis for reviewing resilience strategy effectiveness in multi-hazard prone environments. This framework has particular application to tectonically active areas exposed to climate-change issues.
The Leader Fault was one of at least 17 faults that ruptured the ground surface across the northeastern South Island of New Zealand during the Mw 7.8 2016 Kaikōura Earthquake. The southern ~6 km of the Leader Fault, here referred to as the South Leader Fault (SLF), ruptured the North Canterbury (tectonic) Domain and is the primary focus of this study. The main objective of the thesis is to understand the key factors that contributed to the geometry and kinematics of the 2016 SLF rupture and its intersection with The Humps Fault (HF). This thesis employs a combination of techniques to achieve the primary objective, including detailed mapping of the bedrock geology, geomorphology and 2016 rupture, measurement of 2016 ground surface displacements, kinematic analysis of slip vectors from the earthquake, and logging of a single natural exposure across a 2016 rupture that was treated as a paleoseismic trench. The resulting datasets were collected in the field, from terrestrial LiDAR and InSAR imagery, and from historical (pre-earthquake) aerial photographs for a ~11 km2 study area. Surface ruptures in the study area are a miniature version of the entire rupture from the earthquake; they are geometrically and kinematically complex, with many individual and discontinuous segments of varying orientations and slip senses which are distributed across a zone up to ~3.5 km wide. Despite this variability, three main groups of ruptures have been identified. These are: 1) NE-SW striking, shallow to moderate dipping (25-45°W) faults that are approximately parallel to Cenozoic bedding with mainly reverse dip-slip and, and for the purposes of this thesis, are considered to be part of the SLF. 2) N-S striking, steeply dipping (~85°E) oblique sinistral faults that are up to the west and part of the SLF. 3) E-NE striking, moderate to steeply dipping (45-68°N) dextral reverse faults which are part of the HF. Bedding-parallel faults are interpreted to be flexural slip structures formed during folding of the near-surface Cenozoic strata, while the steeply dipping SLF ruptured a pre-existing bedrock fault which has little topographic expression. Groups 1 and 2 faults were both locally used for gravitational failure during the earthquake. Despite this non-tectonic fault movement, the slip vectors for faults that ruptured during the earthquake are broadly consistent with NCD tectonics and the regional ~100-120° trend of the principal horizontal stress/strain axes. Previous earthquake activity on the SLF is required by its displacement of Cenozoic formations but Late Quaternary slip on the fault prior to 2016 is neither supported by pre-existing fault scarps nor by changes in topography across the fault. By contrast, at least two earthquakes (including 2016) appear to have ruptured the HF from the mid Holocene, consistent with recurrence intervals of no more than ~7 kyr, and with preliminary observations from trenches on the fault farther to the west. The disparity in paleoearthquake records of the two faults suggests that they typically do not rupture together, thus it is concluded that the HF-SLF rupture pattern observed in the Kaikōura Earthquake rarely occurs in a single earthquake.
We estimate the causal effects of a large unanticipated natural disaster on high schoolers’ university enrolment decisions and subsequent medium-term labour market outcomes. Using national administrative data after a destructive earthquake in New Zealand, we estimate that the disaster raises tertiary education enrolment of recent high school graduates by 6.1 percentage points. The effects are most pronounced for males, students who are academically weak relative to their peers, and students from schools directly damaged by the disaster. As relatively low ability males are overrepresented in sectors of the labour market helped by the earthquake, greater demand for university may stem from permanent changes in deeper behavioural parameters such as risk aversion or time preference, rather than as a coping response to poor economic opportunities.
INTRODUCTION This project falls under the Flagship 3: Wellington Coordinated Project. It supports other projects within FP3 to create a holistic understanding of risks posed by collapsed buildings due to future earthquake/s and the secondary consequences of cordoning in the short, mid and long term. Cordoning of the Christchurch CBD for more than two years and its subsequent implications on people and businesses had a significant impact on the recovery of Christchurch. Learning from this and experiences from the Kaikōura earthquake (where cordons were also established around selected buildings, Figure 3) have highlighted the need to understand the effects of cordons and plan for it before an earthquake occurs
On November 14 2016 a magnitude 7.8 earthquake struck the south island of New Zealand. The earthquake lasted for just two minutes with severe seismic shaking and damage in the Hurunui and Kaikōura districts. Although these are predominantly rural areas, with scattered small towns and mountainous topography, they also contain road and rail routes that are essential parts of the national transport infrastructure. This earthquake and the subsequent recovery are of particular significance as they represent a disaster following in close proximity to another similar disaster, with the Canterbury earthquakes occurring in a neighboring district five years earlier. The research used an inductive qualitative case study to explore the nature of the Kaikōura recovery. That recovery process involved a complex interplay between the three parties; (a) the existing local government in the district, (b) central government agencies funding the recovery of the local residents and the national transport infrastructure, and (c) recovery leaders arriving with recent expertise from the earlier Canterbury disaster. It was evident that three groups: locals, government, and experts represented a multi-party governance debate in which the control of the Kaikōura earthquake recovery was shared amongst them. Each party had their own expertise, adgenda and networks that they brought to the Kaikōura recovery, but this created tensions between external expertise and local, community leadership. Recent earthquake research suggests that New Zealand is currently in the midst of an earthquake cluster, with further seismic disasters likely to occur in relatively close succession. This is likely to be compounded by the increasing frequency of other natural disasters with the effects of climate change. The present study investigates a phenomenon that may become increasingly common, with the transfer of disaster expertise from one event to another, and the interface between those experts with local and national government in directing recoveries. The findings of this study have implications for practitioners and policy makers in NZ and other countries where disasters are experienced in close spatial and temporal proximity.
Welcome to the Recover newsletter Issue 2 from the Marine Ecology Research Group (MERG) at the University of Canterbury. Recover is designed to keep you updated on our MBIE funded earthquake recovery project called RECOVER (Reef Ecology, Coastal Values & Earthquake Recovery). This second issue profiles some of the recent work done by our team out in the field!
The level of destruction from the 2011 Christchurch earthquakes led to changes in the New Zealand seismic building code. The destruction showed that the NZ building codes did not fully performed to expectation and needed Improvement to ensure that impact of future earthquakes would be minimised. The building codes have been amended to improve buildings resilience to earthquake and other related extreme loading conditions. Rebuilding Christchurch with the new modifications in the seismic building code comes with its own unique challenges to the entire system. This project investigates the impact of rebuilding Christchurch with the new seismic Building codes in terms of how the new changes affected the building industry and the management of construction.
Introduction In 2011 Christchurch city centre was partially destroyed by an earthquake. Government-led anchor projects were tasked with bringing Christchurch back from rubble. After a period of 7 years out of 16 proposed projects, 10 are already over time for their initial completion dates and the ones completed, are under scrutiny for failing to deliver their expected outcome.
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Following a natural disaster, children are prone to various reactions and maladaptive responses as a result of exposure to a highly stressful and potentially traumatic event. Children’s responses can range from an acute stress response to post-traumatic-stress disorder or may fall somewhere in between. While responses to highly stressful events vary, a common finding is that children will develop sleep problems. This was found following the Christchurch September 2010 and February 2011 earthquakes. The purpose of this study was to investigate the context and phenomenology of the sleep problems of a small number of children experiencing these and the 2016 Kaikoura earthquakes, including possible mechanisms of effect. Participants were four families, including four mothers, one father and four children. The design of this study was unique. Interview data was subjected to a content analysis, extracted themes were organised according to an ecological-transactional framework and then the factors were subject to an analysis, based on the principles of clinical reasoning, in order to identify possible mechanisms of effect. Parents reported 16 different sleep problems across children, as well as other behaviours possibly indicative of post-traumatic stress response. In total, 34 themes and 26 interactions were extracted in relation to factors identified across participants about the children’s sleep and the families’ earthquake experiences. This demonstrated how complex it is to explore the development of sleep problems in the context of disaster. Key factors identified by parents that likely played a key role in the development and perpetuation of sleep problems included earthquake related anxiety, parental mental health and conflict, the child’s emotional and behavioural problems and other negative life events following the earthquakes. The clinical implications of the analysis included being aware that such families, may not have had access to specialized support around their children’s sleep. This was much needed due to the strain such problems place on the family, especially in a post-disaster community such as Christchurch.
La pericolosità associata ad un dato fenomeno costituisce uno dei fattori più importanti e difficili da quantificare nelle analisi di rischio, a maggior ragione quando si tratta di fenomeni complessi come nel caso della liquefazione sismica. Il presente lavoro illustra sinteticamente uno studio della pericolosità indotta al suolo da liquefazione basato su un caso campione statistico particolarmente significativo, il terremoto (Mw 6.2) che ha colpito Christchurch, Nuova Zelanda, del 2011. La notevole mole di dati disponibili, relativi alle caratteristiche geotecniche del sottosuolo, unitamente al rilievo dei danni ha consentito innanzitutto di caratterizzare la suscettibilità a liquefazione dell’area, indipendentemente dall’evento sismico, quindi di correlare statisticamente le diverse grandezze e di derivare delle curve di vulnerabilità del suolo.
We measure the longer-term effect of a major earthquake on the local economy, using night-time light intensity measured from space, and investigate whether insurance claim payments for damaged residential property affected the local recovery process. We focus on the destructive Canterbury Earthquake Sequence (CES) 2010 -2011 as our case study. Uniquely for this event, more than 95% of residential housing units were covered by insurance, but insurance payments were staggered over 5 years, enabling us to identify their local impact. We find that night-time luminosity can capture the process of recovery and describe the recovery’s determinants. We also find that insurance payments contributed significantly to the process of economic recovery after the earthquake, but delayed payments were less affective and cash settlement of claims were more effective than insurance-managed repairs in contributing to local recovery.
Disasters that significantly affect people typically result in the production of documents detailing disaster lessons. This was the case in the 2010 and 2011 Canterbury earthquakes, as government and emergency response agencies, community organisations, and the media, engaged in the practice of producing and reporting disaster lessons. This thesis examines the disaster lessons that were developed by emergent groups following the Canterbury earthquakes (4 September 2010 and 22 February 2011). It adopts a Foucauldian analysis approach to investigate both the construction of disaster lessons and to document how this practice has come to dominate postdisaster activity following the Canterbury earthquakes. The study involved an analysis of academic literature, public documents and websites and interviews with key members of a range of Canterbury based emergent community groups. This material was used to generate a genealogy of disaster lessons, which was given in order to generate an account of how disaster lessons emerged and have come to dominate as a practice of disaster management. The thesis then examines the genealogy through the concept of governmentality so as to demonstrate how this discourse of disaster lessons has come to be used as a governing rationale that shapes and guides the emergent groups conduct in postdisaster New Zealand.
The assessment of damage and remaining capacity after an earthquake is an immediate measure to determine whether a reinforced concrete (RC) building is usable and safe for occupants. The recent Christchurch earthquake (22 February 2011) caused a uniquely severe level of structural damage to modern buildings, resulting in extensive damage to the building stock. About 60% of damaged multistorey concrete buildings (3 storeys and up) were demolished after the earthquake, and the cost of reconstruction amounted to 40 billion NZD. The aftermath disclosed issues of great complexities regarding the future of the RC buildings damaged by the earthquakes. This highlighted the importance of post-event decision-making, as the outcome will allow the appropriate course of action—demolition, repair or acceptance of the existing building—to be considered. To adopt the proper strategy, accurate assessment of the residual capacity and the level of damage is required. This doctoral dissertation aims to assess the damage and remaining capacity at constituent material and member level (i.e., concrete material and beams) through a systematic approach in an attempt to address part of an existing gap in the available literature. Since the residual capacity of RC members is not unique and depends on previously applied loading history, post-event residual capacity in this study was assessed in terms of fraction of fatigue life (i.e., the number of cycles required to failure). This research comprises three main parts: (1) residual capacity and damage assessment at material level (i.e., concrete), (2) post-yield bond deterioration and damage assessment at the interface of steel and concrete, and, finally, (3) residual capacity and damage assessment at member level (i.e., RC beam). The first part of this research focused on damage assessment and the remaining capacity of concrete from a material point of view. It aimed to employ appropriate and reliable durability-based testing and image-detection techniques to quantify deterioration in the mechanical properties of concrete on the basis that stress-induced damage occurred in the microstructural system of the concrete material. To this end, in the first phase, a feasibility study was conducted in which a combination of oxygen permeability, electrical resistivity and porosity tests were assessed to determine if they were robust and reliable enough to reveal damage which occurred in the microstructural system of concrete. The results, in terms of change in permeability, electrical resistivity and porosity features of disk samples taken from the middle third of damaged concrete cylinders (200 mm × 100 mm) monotonically pre-loaded to 50%, 70%, 90% and 95% of the ultimate strength (f′c), showed the permeability test is a reliable tool to identify the degree of damage, due to its high sensitivity to the load-induced microcracking. In parallel, to determine the residual capacity, the companion damaged concrete cylinders already loaded to the same level of compressive strength were reloaded up to failure. Comparing the stress–strain relationship of damaged concrete with intact material, it was also found that the strain capacity of the reloaded pre-damaged concrete cylinders decreases while strength remained virtually unchanged. In the second phase of the first part, a fluorescent microscopy technique was used to assess the damage and develop a correlation between material degradation, by virtue of the geometrical features, and damage to the concrete. To account for the effect of confinement and cyclic loading, in the third phase, the residual capacity and damage assessment of unconfined and GFRP confined concrete cylinders subjected to low-cycle fatigue loading, was investigated. Similar to the first phase, permeability testing technique was used to provide an indirect evaluation of fatigue damage. Finally, in the fourth phase of the first part, the suitability of permeability testing technique to assess damage was evaluated for cored concrete taken from three types of RC members: columns, beams and a beam-column joint. In view of the fact that the composite action of an RC member is highly dependent on the bond between reinforcement and surrounding concrete, understanding the deterioration of the bond in the post-yield range of strain in steel was crucial to assess damage at member level. Therefore, in the second phase of this research, a state-of-the- art distributed fibre optic strain sensor system (DFOSSS) system was used to evaluate bond deterioration in a cantilever RC beam subjected to monotonic lateral loading. The technology allowed the continuous capture of strain, every 2.6 mm along the length, in both reinforcing bars and cover concrete. The strain profile provided a basis by which the slip, axial stress and bond stress distributions were then established. In the third part, the study focused on the damage assessment and residual capacity of seven half-scale RC beams subjected to a constant-amplitude cyclic loading protocol. In the first stage, the structural performances of three specimens under constant-amplitude fatigue at 1%, 2% and 4% chord rotation (drift) were examined. In parallel, the number of cycles to failure, degradation in strength, stiffness and energy dissipation were characterized. In the second stage, four RC beams were subjected to loading up to 70% and 90% of their fatigue life, at 2% and 4% drift, and then monotonically pulled up to failure. To determine the residual flexural capacity, the lateral force–displacement results of pre-damaged specimens were compared with an undamaged specimen subjected to only monotonic loading. The study showed significant losses in strength, deformability, stiffness and energy dissipation capacity. A nonlinear finite element analysis (FEA) using concrete damage plasticity (CDP) model was also conducted in ABAQUS to numerically investigate the behaviour of the tested specimen. The results of the FE simulations indicated a reasonable response compared with the behaviour of the test specimen in terms of force–displacement and cracking pattern. During the Christchurch earthquake it was observed that the loading history has a significant influence on structural responses. While in conventional pseudo-static loading protocol, internal forces can be redistributed along the plastic length: there is little chance for structures undergoing high initial loading amplitude to redistribute pertinent stresses. As a result, in the third phase of this part, the effect of high rate of loading on the behaviour of seismically designed RC beams was investigated. Two half-scale cantilever RC beams were subjected to similar constant-amplitude cyclic loading at 2% and 4% drifts, but at a rate of 500 mm/s. Due to the incapability of conventional measuring techniques, a motion-tracking system was employed for data acquisition with the high-speed tests. The effect of rate of loading on the fatigue life of specimens (i.e., the number of cycles required to failure), secant stiffness, failure mode, cracking pattern, beam elongations and bar fracture surface were analysed. Integrating the results of all parts of this research has resulted in a better understanding of residual capacity and the development of damage at both the material and member level by using a low-cycle fatigue approach.
The 14 November 2016 Kaikōura earthquake had major impacts on New Zealand's transport system. Road, rail and port infrastructure was damaged, creating substantial disruption for transport operators, residents, tourists, and business owners in the Canterbury, Marlborough and Wellington regions, with knock-on consequences elsewhere. During both the response and recovery phases, a large amount of information and data relating to the transport system was generated, managed, analysed, and exchanged within and between organisations to assist decision making. To improve information and data exchanges and related decision making in the transport sector during future events and guide new resilience strategies, we present key findings from a recent post-earthquake assessment. The research involved 35 different stakeholder groups and was conducted for the Ministry of Transport. We consider what transport information was available, its usefulness, where it was sourced from, mechanisms for data transfer between organisations, and suggested approaches for continued monitoring.
This dissertation explores the advocacy for the Christchurch Town Hall that occurred in 2012-2015 after the Canterbury Earthquakes. It frames this advocacy as an instance of collective-action community participation in a heritage decision, and explores the types of heritage values it expressed, particularly social values. The analysis contextualises the advocacy in post-quake Christchurch, and considers its relationship with other developments in local politics, heritage advocacy, and urban activism. In doing so, this dissertation considers how collective action operates as a form of public participation, and the practical implications for understanding and recognising social value. This research draws on studies of practices that underpin social value recognition in formal heritage management. Social value is held by communities outside institutions. Engaging with communities enables institutions to explore the values of specific places, and to realise the potential of activating local connections with heritage places. Such projects can be seen as participatory practices. However, these processes require skills and resources, and may not be appropriate for all places, communities and institutions. However, literature has understudied collective action as a form of community participation in heritage management. All participation processes have nuances of communities, processes, and context, and this dissertation analyses these in one case. The research specifically asked what heritage values (especially social values) were expressed through collective action, what the relationship was with the participation processes, communities, and wider situation that produced them, and the impact on institutional rhetoric and decisions. The research analysed values expressed in representations made to council in support of the Town Hall. It also used documentary sources and interviews with key informants to analyse the advocacy and decision-making processes and their relationships with the wider context and other grassroots activities. The analysis concluded that the values expressed intertwined social and professional values. They were related to the communities and circumstance that produced them, as an advocacy campaign for a civic heritage building from a Western architectural tradition. The advocacy value arguments were one of several factors that impacted the decision. They have had a lasting impact on rhetoric around the Town Hall, as was a heritage-making practice in its own right. This dissertation makes a number of contributions to the discussion of social value and community in heritage. It suggests connections between advocacy and participation perspectives in heritage. It recommends consideration of nuances of communities, context, and place meanings when using heritage advocacy campaigns as evidence of social value. It adds to the literature on heritage advocacy, and offers a focused analysis of one of many heritage debates that occurred in post-quake Christchurch. Ultimately, it encourages practice to actively integrate social and community values and to develop self-reflexive engagement and valuation processes. Despite inherent challenges, participatory processes offer opportunities to diversify understandings of value, co-produce heritage meanings with communities, and empower citizens in democratic processes around the places they live with and love.
Over 900 buildings in the Christchurch central business district and 10,000 residential homes were demolished following the 22nd of February 2011 Canterbury earthquake, significantly disrupting the rebuild progress. This study looks to quantify the time required for demolitions during this event which will be useful for future earthquake recovery planning. This was done using the Canterbury Earthquake Recovery Authority (CERA) demolition database, which allowed an in-depth look into the duration of each phase of the demolition process. The effect of building location, building height, and the stakeholder which initiated the demolition process (i.e. building owner or CERA) was investigated. The demolition process comprises of five phases; (i) decision making, (ii) procurement and planning, (iii) demolition, (iv) site clean-up, and (v) completion certification. It was found that the time required to decide to demolish the building made up majority of the total demolition duration. Demolition projects initiated by CERA had longer procurement and planning durations, but was quicker in other phases. Demolished buildings in the suburbs had a longer decision making duration, but had little effect on other phases of the demolition process. The decision making and procurement and planning phases of the demolition process were shorter for taller buildings, though the other phases took longer. Fragility functions for the duration of each phase in the demolition process are provided for the various categories of buildings for use in future studies.
© 2018 Springer Nature B.V. This study compares seismic losses considering initial construction costs and direct-repair costs for New Zealand steel moment-resisting frame buildings with friction connections and those with extended bolted-end-plate connections. A total of 12 buildings have been designed and analysed considering both connection types, two building heights (4-storey and 12-storey), and three locations around New Zealand (Auckland, Christchurch, and Wellington). It was found that buildings with friction connections required design to a higher design ductility, yet are generally stiffer due to larger beams being required to satisfy higher connection overstrength requirements. This resulted in the frames with friction connections experiencing lower interstorey drifts on most floors but similar peak total floor accelerations, and subsequently incurring lower drift-related seismic repair losses. Frames with friction connections tended to have lower expected net-present-costs within 50 years of the building being in service for shorter buildings and/or if located in regions of high seismicity. None of the frames with friction connections in Auckland showed any benefits due to the low seismicity of the region.
Following the recent earthquakes in Chile (2010) and New Zealand (2010/2011), peculiar failure modes were observed in Reinforced Concrete (RC) walls. These observations have raised a global concern on the contribution of bi-directional loading to these failure mechanisms. One of the failure modes that could potentially result from bidirectional excitations is out-of-plane shear failure. In this paper an overview of the recent experimental and numerical findings regarding out-of-plane shear failure in RC walls are presented. The numerical study presents the Finite Element (FE) simulation of wall D5-6 from the Grand Chancellor Hotel that failed in shear in the out-of-plane direction in the February 2011 Christchurch earthquake. The main objective of the numerical study was to investigate the reasons for this failure mode. The experimental campaign includes the recent experiments conducted in the Structural Engineering Laboratory of the University of Canterbury. The experimental study included three rectangular slender RC walls designed based on NZS3101: 2006-A3 (2017) for three different ductility levels, namely: nominally ductile, limited ductile and ductile. The numerical results showed that high axial load combined with bi-directional loading caused the out-of-plane shear failure in wall D5-6 from the Grand Chancellor Hotel. This was also confirmed and further investigated in the experimental phase of the study.
Observations made in past earthquakes, in New Zealand and around the world, have highlighted the vulnerability of non-structural elements such as facades, ceilings, partitions and services. Damage to these elements can be life-threatening or jeopardise egress routes but typically, the main concern is the cost and time associated with repair works. The Insurance Council of New Zealand highlighted the substantial economic losses in recent earthquakes due to poor performance of non-structural elements. Previous inspections and research have attributed the damage to non-structural elements principally to poor coordination, inadequate or lack of seismic restraints and insufficient clearances to cater for seismic actions. Secondary issues of design responsibility, procurement and the need for better alignment of the various Standards have been identified. In addition to the compliance issues, researchers have also demonstrated that current code provisions for non-structural elements, both in New Zealand and abroad, may be inadequate. This paper first reviews the damage observed against the requirements of relevant Standards and the New Zealand Building Code, and it appears that, had the installations been compliant, the cost of repair and business interruption would have been substantially less. The second part of the paper highlights some of the apparent shortcomings with the current design process for non-structural elements, points towards possible alternative strategies and identifies areas where more research is deemed necessary. The challenge of improving the seismic performance of non-structural elements is a complex one across a diverse construction industry. Indications are that the New Zealand construction industry needs to completely rethink the delivery approach to ensure an integrated design, construction and certification process. The industry, QuakeCentre, QuakeCoRE and the University of Canterbury are presently working together to progress solutions. Indications are that if new processes can be initiated, better performance during earthquakes will be achieved while delivering enhanced building and business resilience.
Asset management in power systems is exercised to improve network reliability to provide confidence and security for customers and asset owners. While there are well-established reliability metrics that are used to measure and manage business-as-usual disruptions, an increasing appreciation of the consequences of low-probability high-impact events means that resilience is increasingly being factored into asset management in order to provide robustness and redundancy to components and wider networks. This is particularly important for electricity systems, given that a range of other infrastructure lifelines depend upon their operation. The 2010-2011 Canterbury Earthquake Sequence provides valuable insights into electricity system criticality and resilience in the face of severe earthquake impacts. While above-ground assets are relatively easy to monitor and repair, underground assets such as cables emplaced across wide areas in the distribution network are difficult to monitor, identify faults on, and repair. This study has characterised in detail the impacts to buried electricity cables in Christchurch resulting from seismically-induced ground deformation caused primarily by liquefaction and lateral spread. Primary modes of failure include cable bending, stretching, insulation damage, joint braking and, being pulled off other equipment such as substation connections. Performance and repair data have been compiled into a detailed geospatial database, which in combination with spatial models of peak ground acceleration, peak ground velocity and ground deformation, will be used to establish rigorous relationships between seismicity and performance. These metrics will be used to inform asset owners of network performance in future earthquakes, further assess component criticality, and provide resilience metrics.
