In the period between September 2010 and December 2011, Christchurch was shaken by a series of strong earthquakes including the MW7.1 4 September 2010, Mw 6.2 22 February 2011, MW6.2 13 June 2011 and MW6.0 23 December 2011 earthquakes. These earthquakes produced very strong ground motions throughout the city and surrounding areas that resulted in soil liquefaction and lateral spreading causing substantial damage to buildings, infrastructure and the community. The stopbank network along the Kaiapoi and Avon River suffered extensive damage with repairs projected to take several years to complete. This presented an opportunity to undertake a case-study on a regional scale of the effects of liquefaction on a stopbank system. Ultimately, this information can be used to determine simple performance-based concepts that can be applied in practice to improve the resilience of river protection works. The research presented in this thesis draws from data collected following the 4th September 2010 and 22nd February 2011 earthquakes. The stopbank damage is categorised into seven key deformation modes that were interpreted from aerial photographs, consultant reports, damage photographs and site visits. Each deformation mode provides an assessment of the observed mechanism of failure behind liquefaction-induced stopbank damage and the factors that influence a particular style of deformation. The deformation modes have been used to create a severity classification for the whole stopbank system, being ‘no or low damage’ and ‘major or severe damage’, in order to discriminate the indicators and factors that contribute to ‘major to severe damage’ from the factors that contribute to all levels of damage a number of calculated, land damage, stopbank damage and geomorphological parameters were analysed and compared at 178 locations along the Kaiapoi and Avon River stopbank systems. A critical liquefiable layer was present at every location with relatively consistent geotechnical parameters (cone resistance (qc), soil behaviour type (Ic) and Factor of Safety (FoS)) across the study site. In 95% of the cases the critical layer occurred within two times the Height of the Free Face (HFF,). A statistical analysis of the geotechnical factors relating to the critical layer was undertaken in order to find correlations between specific deformation modes and geotechnical factors. It was found that each individual deformation mode involves a complex interplay of factors that are difficult to represent through correlative analysis. There was, however, sufficient data to derive the key factors that have affected the severity of deformation. It was concluded that stopbank damage is directly related to the presence of liquefaction in the ground materials beneath the stopbanks, but is not critical in determining the type or severity of damage, instead it is merely the triggering mechanism. Once liquefaction is triggered it is the gravity-induced deformation that causes the damage rather than the shaking duration. Lateral spreading and specifically the depositional setting was found to be the key aspect in determining the severity and type of deformation along the stopbank system. The presence or absence of abandoned or old river channels and point bar deposits was found to significantly influence the severity and type of deformation. A review of digital elevation models and old maps along the Kaiapoi River found that all of the ‘major to severe’ damage observed occurred within or directly adjacent to an abandoned river channel. Whilst a review of the geomorphology along the Avon River showed that every location within a point bar deposit suffered some form of damage, due to the depositional environment creating a deposit highly susceptible to liquefaction.
Sewerage systems convey sewage, or wastewater, from residential or commercial buildings through complex reticulation networks to treatment plants. During seismic events both transient ground motion and permanent ground deformation can induce physical damage to sewerage system components, limiting or impeding the operability of the whole system. The malfunction of municipal sewerage systems can result in the pollution of nearby waterways through discharge of untreated sewage, pose a public health threat by preventing the use of appropriate sanitation facilities, and cause serious inconvenience for rescuers and residents. Christchurch, the second largest city in New Zealand, was seriously affected by the Canterbury Earthquake Sequence (CES) in 2010-2011. The CES imposed widespread damage to the Christchurch sewerage system (CSS), causing a significant loss of functionality and serviceability to the system. The Christchurch City Council (CCC) relied heavily on temporary sewerage services for several months following the CES. The temporary services were supported by use of chemical and portable toilets to supplement the damaged wastewater system. The rebuild delivery agency -Stronger Christchurch Infrastructure Rebuild Team (SCIRT) was created to be responsible for repair of 85 % of the damaged horizontal infrastructure (i.e., water, wastewater, stormwater systems, and roads) in Christchurch. Numerous initiatives to create platforms/tools aiming to, on the one hand, support the understanding, management and mitigation of seismic risk for infrastructure prior to disasters, and on the other hand, to support the decision-making for post-disaster reconstruction and recovery, have been promoted worldwide. Despite this, the CES in New Zealand highlighted that none of the existing platforms/tools are either accessible and/or readable or usable by emergency managers and decision makers for restoring the CSS. Furthermore, the majority of existing tools have a sole focus on the engineering perspective, while the holistic process of formulating recovery decisions is based on system-wide approach, where a variety of factors in addition to technical considerations are involved. Lastly, there is a paucity of studies focused on the tools and frameworks for supporting decision-making specifically on sewerage system restoration after earthquakes. This thesis develops a decision support framework for sewerage pipe and system restoration after earthquakes, building on the experience and learning of the organisations involved in recovering the CSS following the CES in 2010-2011. The proposed decision support framework includes three modules: 1) Physical Damage Module (PDM); 2) Functional Impact Module (FIM); 3) Pipeline Restoration Module (PRM). The PDM provides seismic fragility matrices and functions for sewer gravity and pressure pipelines for predicting earthquake-induced physical damage, categorised by pipe materials and liquefaction zones. The FIM demonstrates a set of performance indicators that are categorised in five domains: structural, hydraulic, environmental, social and economic domains. These performance indicators are used to assess loss of wastewater system service and the induced functional impacts in three different phases: emergency response, short-term recovery and long-term restoration. Based on the knowledge of the physical and functional status-quo of the sewerage systems post-earthquake captured through the PDM and FIM, the PRM estimates restoration time of sewer networks by use of restoration models developed using a Random Forest technique and graphically represented in terms of restoration curves. The development of a decision support framework for sewer recovery after earthquakes enables decision makers to assess physical damage, evaluate functional impacts relating to hydraulic, environmental, structural, economic and social contexts, and to predict restoration time of sewerage systems. Furthermore, the decision support framework can be potentially employed to underpin system maintenance and upgrade by guiding system rehabilitation and to monitor system behaviours during business-as-usual time. In conjunction with expert judgement and best practices, this framework can be moreover applied to assist asset managers in targeting the inclusion of system resilience as part of asset maintenance programmes.
This paper reports on a service-learning public journalism project in which postgraduate journalism students explore ways to engage with and report on diverse communities. Media scholars have argued that news media, and local newspapers in particular, must re-engage with their communities. Likewise, journalism studies scholars have urged educators to give journalism students greater opportunities to reflect on their work by getting out among journalism’s critics, often consumers or citizens concerned about content and the preparation of future journalists. The challenge for journalism educators is to prepare students for working in partnership with communities while also developing their ability to operate reflectively and critically within the expectations of the news media industry and wider society. The aim of this project has been to help students find ways to both listen and lead in a community, and also reflect on the challenges and critiques of community journalism practices. The project began in 2013 with stories about residents’ recovery following the devastating 2011 Canterbury earthquakes, and aimed to create stories that could contribute to community connection and engagement, and thereby resilience and recovery. The idea was inspired by research about post-disaster renewal that indicated that communities with strong social capital and social networks were more resilient and recovered more quickly and strongly. The project’s longer-term aim has been to explore community journalism practices that give greater power to citizens and communities by prioritising listening and processes of engagement. Over several months, students network with a community group to identify subjects with whom they will co-create a story, and then complete a story on which they must seek the feedback of their subject. Community leaders have described the project as a key example of how to do things “with people not to people”, and an outstanding contribution to the community-led component of Canterbury’s recovery. Analysis of student reflections, which are a key part of each year’s project, reveals the process of engaging with communities has helped students to map community dynamics, think more critically about source relationships, editorial choices and objectivity norms, and to develop a perspective on the diverse ways they can go about their journalism in the future. Each year, students partner with different groups and organisations, addressing different themes each time the project runs. For 2016, the programme proposes to develop the project in a new way, by not just exploring a community’s stories but also exploring its media needs and it aims to work with Christchurch’s new migrant Filipino community to develop the groundwork for a community media and/or communication platform, which Filipino community leaders say is a pressing need. For this iteration, journalism students will be set further research tasks aimed at deepening their ‘public listening’: they will conduct a survey of community members’ media use and needs as well as qualitative research interviews. It is hoped that the data collected will strengthen students’ understanding of their own journalism practice, as well as form the basis for work on developing media tools for minority groups who are generally poorly represented in mainstream media. In 2015, the journalism programme surveyed its community partners and held follow-up interviews with 13 of 18 story subjects to elicit further feedback on its news content and thereby deepen understanding of different community viewpoints. The survey and interview data revealed the project affected story subjects in a number of positive and interesting ways. Subjects said they appreciated the way student reporters took their time to build relationships and understand the context of the community groups with which they were involved, and contrasted this with their experience of professional journalists who had held pre-conceived assumptions about stories and/or rushed into interviews. As a direct consequence of the students’ approach, participants said they better trusted the student journalists to portray them accurately and fairly. Most were also encouraged by the positive recognition stories brought and several said the engagement process had helped their personal development, all of which had spin-offs for their community efforts. The presentation night that wraps up each year’s project, where community groups, story subjects and students come together to network and share the final stories, was cited as a significant positive aspect of the project and a great opportunity for community partners to connect with others doing similar work. Community feedback will be sought in future projects to inform and improve successive iterations.
Research on responses to trauma has historically focused on the negative repercussions of a struggle with adversity. However, more recently, researchers have begun to examine posttraumatic growth: the positive psychological change that emerges from the struggle with a potentially traumatic event. Associations have been found between posttraumatic growth and greater peritraumatic distress, greater objective severity of trauma exposure, greater perceived stressfulness of events, social support, female gender, cognitive and behavioural responses to trauma, and personality measures. Posttraumatic growth has been measured typically in individuals with varying levels of posttraumatic stress disorder symptoms and other psychological difficulties, such as depression and anxiety. Although some theory and research posits that higher resilience would prohibit posttraumatic growth, no studies have examined posttraumatic growth in a resilient sample. The Canterbury earthquake sequence of 2010 and 2011 involved potentially traumatic events that saw the community struggle with a variety of challenges. However, in the midst of earthquake destruction, some positive initiatives emerged, driven by locals. The Gap Filler project (using city spaces left empty from fallen buildings for art and interactive community projects) and the Student Volunteer Army (groups of volunteers coordinated to help others in need) are examples of this. In this context, it seemed likely that posttraumatic growth was occurring and might be seen in individuals who were coping well with challenges. Culture is theorised to influence the posttraumatic growth process (Calhoun, Cann, & Tedeschi, 2010), and the nature of the trauma undergone is also likely to influence the process of growth. The current thesis measures posttraumatic growth quantitatively and qualitatively in a New Zealand sample. It measures and describes posttraumatic growth in a resilient population after the earthquake sequence of 2010 and 2011 in Canterbury, New Zealand. Findings are used to test current models of posttraumatic growth for individuals coping well after trauma and to elaborate on mechanisms proposed by models such as the comprehensive model of posttraumatic growth (Calhoun et al., 2010) and the organismic valuing theory of growth through adversity (Joseph & Linley, 2005). Correlates of posttraumatic growth are examined and likely supporting factors of posttraumatic growth are identified for this population. Study 1 used quantitative analysis to explore correlates of posttraumatic growth and found that greater posttraumatic growth related to greater peritraumatic distress, greater perceived stressfulness of earthquake events, greater objective stressfulness of earthquake events, greater difficulty with stressful life events, less satisfaction with social support, and female gender. Findings from Study 1 give important detail about the nature of distress included in the comprehensive model of posttraumatic growth (Calhoun et al., 2010) for this population. Levels of posttraumatic growth were lower than those in North American studies but similar to those in a Chinese study. The current sample, however, showed lower endorsement of Relating to Others than the Chinese study, perhaps because of cultural differences. Study 2 used qualitative analysis to examine the experience of posttraumatic growth in the sample. The theme of ‘a greater sense of community’ was found and adds to the comprehensive model of posttraumatic growth, in that an expression of posttraumatic growth (a greater connection with others) can inform ongoing social processing in the posttraumatic growth process. Having a formal or informal role in earthquake recovery appeared to influence self-concept and reflection; this elaborates on the influence of role on reflection in Calhoun et al.’s model. Findings illustrate possible mechanisms of the organismic valuing process theorised by Joseph and Linley (2005). Implications include the importance of providing opportunities for individuals to take on a role after a crisis, encouraging them to act to respond to difficulties, and encouraging them to meet personal needs for relatedness, competence, and autonomy. Finding positive aspects to a difficult situation, as well as acknowledging adversity, can be supported in future to help individuals process their traumas. As a society, we can help individuals cope with adversity by providing ways they can meet their needs for relatedness, competence, and autonomy. Community groups likely provide opportunities for members to act in ways that meet such needs. This will allow them to effectively act to meet their needs in times of crisis.
The city of Ōtautahi/Christchurch experienced a series of earthquakes that began on September 4th, 2010. The most damaging event occurred on February 22nd, 2011 but significant earthquakes also occurred on June 13th and December 23rd with aftershocks still occurring well into 2012. The resulting disaster is the second deadliest natural disaster in New Zealand’s history with 185 deaths. During 2011 the Canterbury earthquakes were one of the costliest disasters worldwide with an expected cost of up to $NZ30 billion.
Hundreds of commercial buildings and thousands of houses have been destroyed or are to be demolished and extensive repairs are needed for infrastructure to over 100,000 homes. As many as 8,900 people simply abandoned their homes and left the city in the first few months after the February event (Newell, 2012), and as many as 50,000 may leave during 2012. In particular, young whānau and single young women comprised a disproportionate number of these migrants, with evidence of a general movement to the North Island.
Te Puni Kōkiri sought a mix of quantitative and qualitative research to examine the social and economic impacts of the Christchurch earthquakes on Māori and their whānau. The result of this work will be a collection of evidence to inform policy to support and assist Māori and their whānau during the recovery/rebuild phases. To that end, this report triangulates available statistical and geographical information with qualitative data gathered over 2010 and 2011 by a series of interviews conducted with Māori who experienced the dramatic events associated with the earthquakes.
A Māori research team at Lincoln University was commissioned to undertake the research as they were already engaged in transdisciplinary research (began in the May 2010), that focused on quickly gathering data from a range of Māori who experienced the disaster, including relevant economic, environmental, social and cultural factors in the response and recovery of Māori to these events.
Participants for the qualitative research were drawn from Māori whānau who both stayed and left the city. Further data was available from ongoing projects and networks that the Lincoln research team was already involved in, including interviews with Māori first responders and managers operating in the CBD on the day of the February event. Some limited data is also available from younger members of affected whānau.
Māori in Ōtautahi/Christchurch City have exhibited their own culturally-attuned collective responses to the disaster. However, it is difficult to ascertain Māori demographic changes due to a lack of robust statistical frameworks but Māori outward migration from the city is estimated to range between 560 and 1,100 people.
The mobility displayed by Māori demonstrates an important but unquantified response by whānau to this disaster, with emigration to Australia presenting an attractive option for young Māori, an entrenched phenomenon that correlates to cyclical downturns and the long-term decline of the New Zealand economy. It is estimated that at least 315 Māori have emigrated from the Canterbury region to Australia post-quake, although the disaster itself may be only one of a series of events that has prompted such a decision.
Māori children made up more than one in four of the net loss of children aged 6 to 15 years enrolled in schools in Greater Christchurch over the year to June 2011. Research literature identifies depression affecting a small but significant number of children one to two years post-disaster and points to increasing clinical and organisational demands for Māori and other residents of the city.
For those residents in the eastern or coastal suburbs – home to many of the city’s Māori population - severe damage to housing, schools, shops, infrastructure, and streets has meant disruption to their lives, children’s schooling, employment, and community functioning. Ongoing abandonment of homes by many has meant a growing sense of unease and loss of security, exacerbated by arson, burglaries, increased drinking, a stalled local and national economy, and general confusion about the city’s future.
Māori cultural resilience has enabled a considerable network of people, institutions, and resources being available to Māori , most noticeably through marae and their integral roles of housing, as a coordinating hub, and their arguing for the wider affected communities of Christchurch.
Relevant disaster responses need to be discussed within whānau, kōhanga, kura, businesses, communities, and wider neighbourhoods. Comprehensive disaster management plans need to be drafted for all iwi in collaboration with central government, regional, and city or town councils.
Overall, Māori are remarkably philosophical about the effects of the disaster, with many proudly relishing their roles in what is clearly a historic event of great significance to the city and country. Most believe that ‘being Māori’ has helped cope with the disaster, although for some this draws on a collective history of poverty and marginalisation, features that contribute to the vulnerability of Māori to such events.
While the recovery and rebuild phases offer considerable options for Māori and iwi, with Ngāi Tahu set to play an important stakeholder in infrastructural, residential, and commercial developments, some risk and considerable unknowns are evident. Considerable numbers of Māori may migrate into the Canterbury region for employment in the rebuild, and trades training strategies have already been established.
With many iwi now increasingly investing in property, the risks from significant earthquakes are now more transparent, not least to insurers and the reinsurance sector. Iwi authorities need to be appraised of insurance issues and ensure sufficient coverage exists and investments and developments are undertaken with a clear understanding of the risks from natural hazards and exposure to future disasters.
The research is funded by Callaghan Innovation (grant number MAIN1901/PROP-69059-FELLOW-MAIN) and the Ministry of Transport New Zealand in partnership with Mainfreight Limited. Need – The freight industry is facing challenges related to climate change, including natural hazards and carbon emissions. These challenges impact the efficiency of freight networks, increase costs, and negatively affect delivery times. To address these challenges, freight logistics modelling should consider multiple variables, such as natural hazards, sustainability, and emission reduction strategies. Freight operations are complex, involving various factors that contribute to randomness, such as the volume of freight being transported, the location of customers, and truck routes. Conventional methods have limitations in simulating a large number of variables. Hence, there is a need to develop a method that can incorporate multiple variables and support freight sustainable development. Method - A minimal viable model (MVM) method was proposed to elicit tacit information from industrial clients for building a minimally sufficient simulation model at the early modelling stages. The discrete-event simulation (DES) method was applied using Arena® software to create simulation models for the Auckland and Christchurch corridor, including regional pick-up and delivery (PUD) models, Christchurch city delivery models, and linehaul models. Stochastic variables in freight operations such as consignment attributes, customer locations, and truck routes were incorporated in the simulation. The geographic information system (GIS) software ArcGIS Pro® was used to identify and analyse industrial data. The results obtained from the GIS software were applied to create DES models. Life cycle assessment (LCA) models were developed for both diesel and battery electric (BE) trucks to compare their life cycle greenhouse gas (GHG) emissions and total cost of ownership (TCO) and support GHG emissions reduction. The line-haul model also included natural hazards in several scenarios, and the simulation was used to forecast the stock level of Auckland and Christchurch depots in response to each corresponding scenario. Results – DES is a powerful technique that can be employed to simulate and evaluate freight operations that exhibit high levels of variability, such as regional pickup and delivery (PUD) and linehaul. Through DES, it becomes possible to analyse multiple factors within freight operations, including transportation modes, routes, scheduling, and processing times, thereby offering valuable insights into the performance, efficiency, and reliability of the system. In addition, GIS is a useful tool for analysing and visualizing spatial data in freight operations. This is exemplified by their ability to simulate the travelling salesman problem (TSP) and conduct cluster analysis. Consequently, the integration of GIS into DES modelling is essential for improving the accuracy and reliability of freight operations analysis. The outcomes of the simulation were utilised to evaluate the ecological impact of freight transport by performing emission calculations and generating low-carbon scenarios to identify approaches for reducing the carbon footprint. LCA models were developed based on simulation results. Results showed that battery-electric trucks (BE) produced more greenhouse gas (GHG) emissions in the cradle phase due to battery manufacturing but substantially less GHG emissions in the use phase because of New Zealand's mostly renewable energy sources. While the transition to BE could significantly reduce emissions, the financial aspect is not compelling, as the total cost of ownership (TCO) for the BE truck was about the same for ten years, despite a higher capital investment for the BE. Moreover, external incentives are necessary to justify a shift to BE trucks. By using simulation methods, the effectiveness of response plans for natural hazards can be evaluated, and the system's vulnerabilities can be identified and mitigated to minimize the risk of disruption. Simulation models can also be utilized to simulate adaptation plans to enhance the system's resilience to natural disasters. Novel contributions – The study employed a combination of DES and GIS methods to incorporate a large number of stochastic variables and driver’s decisions into freight logistics modelling. Various realistic operational scenarios were simulated, including customer clustering and PUD truck allocation. This showed that complex pickup and delivery routes with high daily variability can be represented using a model of roads and intersections. Geographic regions of high customer density, along with high daily variability could be represented by a two-tier architecture. The method could also identify delivery runs for a whole city, which has potential usefulness in market expansion to new territories. In addition, a model was developed to address carbon emissions and total cost of ownership of battery electric trucks. This showed that the transition was not straightforward because the economics were not compelling, and that policy interventions – a variety were suggested - could be necessary to encourage the transition to decarbonised freight transport. A model was developed to represent the effect of natural disasters – such as earthquake and climate change – on road travel and detour times in the line haul freight context for New Zealand. From this it was possible to predict the effects on stock levels for a variety of disruption scenarios (ferry interruption, road detours). Results indicated that some centres rather than others may face higher pressure and longer-term disturbance after the disaster subsided. Remedies including coastal shipping were modelled and shown to have the potential to limit the adverse effects. A philosophical contribution was the development of a methodology to adapt the agile method into the modelling process. This has the potential to improve the clarification of client objectives and the validity of the resulting model.
In the last century, seismic design has undergone significant advancements. Starting from the initial concept of designing structures to perform elastically during an earthquake, the modern seismic design philosophy allows structures to respond to ground excitations in an inelastic manner, thereby allowing damage in earthquakes that are significantly less intense than the largest possible ground motion at the site of the structure. Current performance-based multi-objective seismic design methods aim to ensure life-safety in large and rare earthquakes, and to limit structural damage in frequent and moderate earthquakes. As a result, not many recently built buildings have collapsed and very few people have been killed in 21st century buildings even in large earthquakes. Nevertheless, the financial losses to the community arising from damage and downtime in these earthquakes have been unacceptably high (for example; reported to be in excess of 40 billion dollars in the recent Canterbury earthquakes). In the aftermath of the huge financial losses incurred in recent earthquakes, public has unabashedly shown their dissatisfaction over the seismic performance of the built infrastructure. As the current capacity design based seismic design approach relies on inelastic response (i.e. ductility) in pre-identified plastic hinges, it encourages structures to damage (and inadvertently to incur loss in the form of repair and downtime). It has now been widely accepted that while designing ductile structural systems according to the modern seismic design concept can largely ensure life-safety during earthquakes, this also causes buildings to undergo substantial damage (and significant financial loss) in moderate earthquakes. In a quest to match the seismic design objectives with public expectations, researchers are exploring how financial loss can be brought into the decision making process of seismic design. This has facilitated conceptual development of loss optimisation seismic design (LOSD), which involves estimating likely financial losses in design level earthquakes and comparing against acceptable levels of loss to make design decisions (Dhakal 2010a). Adoption of loss based approach in seismic design standards will be a big paradigm shift in earthquake engineering, but it is still a long term dream as the quantification of the interrelationships between earthquake intensity, engineering demand parameters, damage measures, and different forms of losses for different types of buildings (and more importantly the simplification of the interrelationship into design friendly forms) will require a long time. Dissecting the cost of modern buildings suggests that the structural components constitute only a minor portion of the total building cost (Taghavi and Miranda 2003). Moreover, recent research on seismic loss assessment has shown that the damage to non-structural elements and building contents contribute dominantly to the total building loss (Bradley et. al. 2009). In an earthquake, buildings can incur losses of three different forms (damage, downtime, and death/injury commonly referred as 3Ds); but all three forms of seismic loss can be expressed in terms of dollars. It is also obvious that the latter two loss forms (i.e. downtime and death/injury) are related to the extent of damage; which, in a building, will not just be constrained to the load bearing (i.e. structural) elements. As observed in recent earthquakes, even the secondary building components (such as ceilings, partitions, facades, windows parapets, chimneys, canopies) and contents can undergo substantial damage, which can lead to all three forms of loss (Dhakal 2010b). Hence, if financial losses are to be minimised during earthquakes, not only the structural systems, but also the non-structural elements (such as partitions, ceilings, glazing, windows etc.) should be designed for earthquake resistance, and valuable contents should be protected against damage during earthquakes. Several innovative building technologies have been (and are being) developed to reduce building damage during earthquakes (Buchanan et. al. 2011). Most of these developments are aimed at reducing damage to the buildings’ structural systems without due attention to their effects on non-structural systems and building contents. For example, the PRESSS system or Damage Avoidance Design concept aims to enable a building’s structural system to meet the required displacement demand by rocking without the structural elements having to deform inelastically; thereby avoiding damage to these elements. However, as this concept does not necessarily reduce the interstory drift or floor acceleration demands, the damage to non-structural elements and contents can still be high. Similarly, the concept of externally bracing/damping building frames reduces the drift demand (and consequently reduces the structural damage and drift sensitive non-structural damage). Nevertheless, the acceleration sensitive non-structural elements and contents will still be very vulnerable to damage as the floor accelerations are not reduced (arguably increased). Therefore, these concepts may not be able to substantially reduce the total financial losses in all types of buildings. Among the emerging building technologies, base isolation looks very promising as it seems to reduce both inter-storey drifts and floor accelerations, thereby reducing the damage to the structural/non-structural components of a building and its contents. Undoubtedly, a base isolated building will incur substantially reduced loss of all three forms (dollars, downtime, death/injury), even during severe earthquakes. However, base isolating a building or applying any other beneficial technology may incur additional initial costs. In order to provide incentives for builders/owners to adopt these loss-minimising technologies, real-estate and insurance industries will have to acknowledge the reduced risk posed by (and enhanced resilience of) such buildings in setting their rental/sale prices and insurance premiums.
Natural hazard disasters often have large area-wide impacts, which can cause adverse stress-related mental health outcomes in exposed populations. As a result, increased treatment-seeking may be observed, which puts a strain on the limited public health care resources particularly in the aftermath of a disaster. It is therefore important for public health care planners to know whom to target, but also where and when to initiate intervention programs that promote emotional wellbeing and prevent the development of mental disorders after catastrophic events. A large body of literature assesses factors that predict and mitigate disaster-related mental disorders at various time periods, but the spatial component has rarely been investigated in disaster mental health research. This thesis uses spatial and spatio-temporal analysis techniques to examine when and where higher and lower than expected mood and anxiety symptom treatments occurred in the severely affected Christchurch urban area (New Zealand) after the 2010/11 Canterbury earthquakes. High-risk groups are identified and a possible relationship between exposure to the earthquakes and their physical impacts and mood and anxiety symptom treatments is assessed. The main research aim is to test the hypothesis that more severely affected Christchurch residents were more likely to show mood and anxiety symptoms when seeking treatment than less affected ones, in essence, testing for a dose-response relationship. The data consisted of mood and anxiety symptom treatment information from the New Zealand Ministry of Health’s administrative databases and demographic information from the National Health Index (NHI) register, when combined built a unique and rich source for identifying publically funded stress-related treatments for mood and anxiety symptoms in almost the whole population of the study area. The Christchurch urban area within the Christchurch City Council (CCC) boundary was the area of interest in which spatial variations in these treatments were assessed. Spatial and spatio-temporal analyses were done by applying retrospective space-time and spatial variation in temporal trends analysis using SaTScan™ software, and Bayesian hierarchical modelling techniques for disease mapping using WinBUGS software. The thesis identified an overall earthquake-exposure effect on mood and anxiety symptom treatments among Christchurch residents in the context of the earthquakes as they experienced stronger increases in the risk of being treated especially shortly after the catastrophic 2011 Christchurch earthquake compared to the rest of New Zealand. High-risk groups included females, elderly, children and those with a pre-existing mental illness with elderly and children especially at-risk in the context of the earthquakes. Looking at the spatio-temporal distribution of mood and anxiety symptom treatments in the Christchurch urban area, a high rates cluster ranging from the severely affected central city to the southeast was found post-disaster. Analysing residential exposure to various earthquake impacts found that living in closer proximity to more affected areas was identified as a risk factor for mood and anxiety symptom treatments, which largely confirms a dose-response relationship between level of affectedness and mood and anxiety symptom treatments. However, little changes in the spatial distribution of mood and anxiety symptom treatments occurred in the Christchurch urban area over time indicating that these results may have been biased by pre-existing spatial disparities. Additionally, the post-disaster mobility activity from severely affected eastern to the generally less affected western and northern parts of the city seemed to have played an important role as the strongest increases in treatment rates occurred in less affected northern areas of the city, whereas the severely affected eastern areas tended to show the lowest increases. An investigation into the different effects of mobility confirmed that within-city movers and temporary relocatees were generally more likely to receive care or treatment for mood or anxiety symptoms, but moving within the city was identified as a protective factor over time. In contrast, moving out of the city from minor, moderately or severely damaged plain areas of the city, which are generally less affluent than Port Hills areas, was identified as a risk factor in the second year post-disaster. Moreover, residents from less damaged plain areas of the city showed a decrease in the likelihood of receiving care or treatment for mood or anxiety symptoms compared to those from undamaged plain areas over time, which also contradicts a possible dose-response relationship. Finally, the effects of the social and physical environment, as well as community resilience on mood and anxiety symptom treatments among long-term stayers from Christchurch communities indicate an exacerbation of pre-existing mood and anxiety symptom treatment disparities in the city, whereas exposure to ‘felt’ earthquake intensities did not show a statistically significant effect. The findings of this thesis highlight the complex relationship between different levels of exposure to a severe natural disaster and adverse mental health outcomes in a severely affected region. It is one of the few studies that have access to area-wide health and impact information, are able to do a pre-disaster / post-disaster comparison and track their sample population to apply spatial and spatio-temporal analysis techniques for exposure assessment. Thus, this thesis enhances knowledge about the spatio-temporal distribution of adverse mental health outcomes in the context of a severe natural disaster and informs public health care planners, not only about high-risk groups, but also where and when to target health interventions. The results indicate that such programs should broadly target residents living in more affected areas as they are likely to face daily hardship by living in a disrupted environment and may have already been the most vulnerable ones before the disaster. Special attention should be focussed on women, elderly, children and people with pre-existing mental illnesses as they are most likely to receive care or treatment for stress-related mental health symptoms. Moreover, permanent relocatees from affected areas and temporarily relocatees shortly after the disaster may need special attention as they face additional stressors due to the relocation that may lead to the development of adverse mental health outcomes needing treatment.
Non-structural elements (NSEs) have frequently proven to contribute to significant losses sustained from earthquakes in the form of damage, downtime, injury and death. In New Zealand (NZ), the 2010 and 2011 Canterbury Earthquake Sequence (CES), the 2013 Seddon and Cook Strait earthquake sequence and the 2016 Kaikoura earthquake were major milestones in this regard as significant damage to building NSEs both highlighted and further reinforced the importance of NSE seismic performance to the resilience of urban centres. Extensive damage in suspended ceilings, partition walls, façades and building services following the CES was reported to be partly due to erroneous seismic design or installation or caused by intervening elements. Moreover, the low-damage solutions developed for structural systems sometimes allow for relatively large inter-story drifts -compared to conventional designs- which may not have been considered in the seismic design of NSEs. Having observed these shortcomings, this study on suspended ceilings was carried out with five main goals: i) Understanding the seismic performance of the system commonly used in NZ; ii) Understanding the transfer of seismic design actions through different suspended ceiling components, iii) Investigating potential low-damage solutions; iii) Evaluating the compatibility of the current ceiling system with other low-damage NSEs; and iv) Investigating the application of numerical analysis to simulate the response of ceiling systems. The first phase of the study followed a joint research work between the University of Canterbury (UC) in NZ, and the Politecnico Di Milano, in Italy. The experimental ceiling component fragility curves obtained in this existing study were employed to produce analytical fragility curves for a perimeter-fixed ceiling of a given size and weight, with grid acceleration as the intensity measure. The validity of the method was proven through comparisons between this proposed analytical approach with the recommended procedures in proprietary products design guidelines, as well as experimental fragility curves from other studies. For application to engineering design practice, and using fragility curves for a range of ceiling lengths and weights, design curves were produced for estimating the allowable grid lengths for a given demand level. In the second phase of this study, three specimens of perimeter-fixed ceilings were tested on a shake table under both sinusoidal and random floor motion input. The experiments considered the relationship between the floor acceleration, acceleration of the ceiling grid, the axial force induced in the grid members, and the effect of boundary conditions on the transfer of these axial forces. A direct correlation was observed between the axial force (recorded via load cells) and the horizontal acceleration measured on the ceiling grid. Moreover, the amplification of floor acceleration, as transferred through ceiling components, was examined and found (in several tests) to be greater than the recommended factor for the design of ceilings provided in the NZ earthquake loadings standard NZS1170.5. However, this amplification was found to be influenced by the pounding interactions between the ceiling grid members and the tiles, and this amplification diminished considerably when the high frequency content was filtered out from the output time histories. The experiments ended with damage in the ceiling grid connection at an axial force similar to the capacity of these joints previously measured through static tests in phase one. The observation of common forms of damage in ceilings in earthquakes triggered the monotonic experiments carried out in the third phase of this research with the objective of investigating a simple and easily applicable mitigation strategy for existing or new suspended ceilings. The tests focused on the possibility of using proprietary cross-shaped clip elements ordinarily used to provide seismic gap as a strengthening solution for the weak components of a ceiling. The results showed that the solution was effective under both tension and compression loads through increasing load bearing capacity and ductility in grid connections. The feasibility of a novel type of suspended ceiling called fully-floating ceiling system was investigated through shaking table tests in the next phase of this study with the main goal of isolating the ceiling from the surrounding structure; thereby arresting the transfer of associated seismic forces from the structure to the ceiling. The fully-floating ceiling specimen was freely hung from the floor above lacking any lateral bracing and connections with the perimeter. Throughout different tests, a satisfactory agreement between the fully-floating ceiling response and simple pendulum theory was demonstrated. The addition of isolation material in perimeter gaps was found effective in inducing extra damping and protecting the ceiling from pounding impact; resulting in much reduced ceiling displacements and accelerations. The only form of damage observed throughout the random floor motion tests and the sinusoidal tests was a panel dislodgement observed in a test due to successive poundings between the ceiling specimen and the surrounding beams at resonant frequencies. Partition walls as the first effective NSE in direct interaction with ceilings were the topic of the final experimental phase. Low-damage drywall partitions proposed in a previous study in the UC were tested with two common forms of suspended ceiling: braced and perimeter-fixed. The experiments investigated the in-plane and out-of-plane performance of the low-damage drywall partitions, as well as displacement compatibility between these walls and the suspended ceilings. In the braced ceiling experiment, where no connection was made between ceiling grids and surrounding walls no damage in the grid system or partitions was observed. However, at high drift values panel dislodgement was observed on corners of the ceiling where the free ends of grids were not restrained against spreading. This could be prevented by framing the grid ends using a perimeter angle that is riveted only to the grid members while keeping sufficient clearance from the perimeter walls. In the next set of tests with the perimeter-fixed ceiling, no damage was observed in the ceiling system or the drywalls. Based on the results of the experiments it was concluded that the tested ceiling had enough flexibility to accommodate the relative displacement between two perpendicular walls up to the inter-storey drifts achieved. The experiments on perimeter-fixed ceilings were followed by numerical simulations of the performance of these ceilings in a finite element model developed in the structural analysis software, SAP2000. This model was relatively simple and easy to develop and was able to replicate the experimental results to a reasonable degree. Filtering was applied to the experimental output to exclude the effect of high frequency noise and tile-grid impact. The developed model generally simulated the acceleration responses well but underestimated the peak ceiling grid accelerations. This was possibly because the peak values in time histories were affected by impact occurring at very short periods. The model overestimated the axial forces in ceiling grids which was assumed to be caused by the initial assumptions made about the tributary area or constant acceleration associated with each grid line in the direction of excitation. Otherwise, the overall success of the numerical modelling in replicating the experimental results implies that numerical modelling using conventional structural analysis software could be used in engineering practice to analyse alternative ceiling geometries proposed for application to varying structural systems. This however, needs to be confirmed through similar analyses on other ceiling examples from existing instrumented buildings during real earthquakes. As the concluding part of this research the final phase addressed the issues raised following the review of existing ceiling standards and guidelines. The applicability of the research findings to current practice and their implications were discussed. Finally, an example was provided for the design of a suspended ceiling utilising the new knowledge acquired in this research.
