Researchers have begun to explore the opportunity presented by blue-green infrastructure(a subset of nature-based solutions that provide blue and green space in urban infrastructure)as a response to the pressures of climate change. The 2010/2011 Canterbury earthquake sequence created a unique landscape within which there is opportunity to experiment with and invest in new solutions to climate change adaptation in urban centres. Constructed wetlands are an example of blue-green infrastructure that can potentially support resilience in urban communities. This research explores interactions between communities and constructed wetlands to understand how this may influence perceptions of community resilience. The regeneration of the Ōtākaro Avon River Corridor (OARC) provides a space to investigate these relationships. Seven stakeholders from the community, industry, and academia, each with experience in blue-green infrastructure in the OARC, participated in a series of semi-structured interviews. Each participant was given the opportunity to reflect on their perspectives of community, community resilience, and constructed wetlands and their interconnections. Interview questions aligned with the overarching research objectives to (1) understand perceptions around the role of wetlands in urban communities, (2) develop a definition for community resilience in the context of the Ōtākaro Avon community, and (3) reflect on how wetlands can contribute to (or detract from) community resilience. This study found that constructed wetlands can facilitate learning about the challenges and solutions needed to adapt to climate change. From the perspective of the community representatives, community resilience is linked to social capital. Strong social networks and a relationship with nature were emphasised as core components of a community’s ability to adapt to disruption. Constructed wetlands are therefore recognised as potentially contributing to community resilience by providing spaces for people to engage with each other and nature. Investment in constructed wetlands can support a wider response to climate change impacts. This research was undertaken with the support of the Ōtākaro Living Laboratory Trust, who are invested in the future of the OARC. The outcomes of this study suggest that there is an opportunity to use wetland spaces to establish programmes that explore the perceptions of constructed wetlands from a broader community definition, at each stage of the wetland life cycle, and at wider scales(e.g., at a city scale or beyond).
Anyone keeping a global tally of recent disasters is likely to be asking: What role will the hazards and disasters of coastal plains play in the lives and economies of 21st century humanity? In this article, we reflect on this question using examples of how different types of coastal land performed during the Christchurch and other earthquake events to examine the complex of coastal-tectonic hazards that are being constructed in the Tokyo megacity
A seismic financial risk analysis of typical New Zealand reinforced concrete buildings constructed with topped precast concrete hollow-core units is performed on the basis of experimental research undertaken at the University of Canterbury over the last five years. An extensive study that examines seismic demands on a variety of multi-storey RC buildings is described and supplemented by the experimental results to determine the inter-storey drift capacities of the buildings. Results of a full-scale precast concrete super-assemblage constructed and tested in the laboratory in two stages are used. The first stage investigates existing construction and demonstrates major shortcomings in construction practice that would lead to very poor seismic performance. The second stage examines the performance of the details provided by Amendment No. 3 to the New Zealand Concrete Design Code NZS 3101:1995. This paper uses a probabilistic financial risk assessment framework to estimate the expected annual loss (EAL) from previously developed fragility curves of RC buildings with precast hollow core floors connected to the frames according to the pre-2004 standard and the two connection details recommended in the 2004 amendment. Risks posed by different levels of damage and by earthquakes of different frequencies are examined. The structural performance and financial implications of the three different connection details are compared. The study shows that the improved connection details recommended in the 2004 amendment give a significant economic payback in terms of drastically reduced financial risk, which is also representative of smaller maintenance cost and cheaper insurance premiums.
The ultimate goal of this study is to develop a model representing the in-plane behaviour of plasterboard ceiling diaphragms, as part of the efforts towards performance-based seismic engineering of low-rise light timber-framed (LTF) residential buildings in New Zealand (NZ). LTF residential buildings in NZ are constructed according to a prescriptive standard – NZS 3604 Timberframed buildings [1]. With regards to seismic resisting systems, LTF buildings constructed to NZS3604 often have irregular bracing arrangements within a floor plane. A damage survey of LTF buildings after the Canterbury earthquake revealed that structural irregularity (irregular bracing arrangement within a plane) significantly exacerbated the earthquake damage to LTF buildings. When a building has irregular bracing arrangements, the building will have not only translational deflections but also a torsional response in earthquakes. How effectively the induced torsion can be resolved depends on the stiffness of the floors/roof diaphragms. Ceiling and floor diaphragms in LTF buildings in NZ have different construction details from the rest of the world and there appears to be no information available on timber diaphragms typical of NZ practice. This paper presents experimental studies undertaken on plasterboard ceiling diaphragms as typical of NZ residential practice. Based on the test results, a mathematical model simulating the in-plane stiffness of plasterboard ceiling diaphragms was developed, and the developed model has a similar format to that of plasterboard bracing wall elements presented in an accompany paper by Liu [2]. With these two models, three-dimensional non-linear push-over studies of LTF buildings can be undertaken to calculate seismic performance of irregular LTF buildings.
Following the 2010/2011 Canterbury earthquakes a detailed campaign of door to door assessments was conducted in a variety of areas of Christchurch to establish the earthquake performance of residential dwellings having masonry veneer as an external cladding attached to a lightweight timber framing system. Specifically, care was taken to include regions of Christchurch which experienced different levels of earthquake shaking in order to allow comparison between the performance of different systems and different shaking intensities. At the time of the inspections the buildings in the Christchurch region had been repeatedly subjected to large earthquakes, presenting an opportunity for insight into the seismic performance of masonry veneer cladding. In total just under 1100 residential dwellings were inspected throughout the wider Christchurch area, of which 24% were constructed using the older nail-on veneer tie system (prior to 1996) and 76% were constructed using screw fixed ties to comply with the new 1996 standards revision (post-1996), with 30% of all inspected houses being of two storey construction. Of the inspected dwellings 27% had some evidence of liquefaction, ground settlement or lateral spreading. Data such as damage level, damage type, crack widths, level of repair required and other parameters were collected during the survey. A description of the data collection processes and a snapshot of the analysis results are presented within. http://15ibmac.com/home/
Christchurch Ōtautahi, New Zealand, is a city of myriad waterways and springs. Māori, the indigenous people of New Zealand, have water quality at the core of their cultural values. The city’s rivers include the Avon/Ōtākaro, central to the city centre’s aesthetic appeal since early settlement, and the Heathcote/Ōpāwaho. Both have been degraded with increasing urbanisation. The destructive earthquake sequence that occurred during 2010/11 presented an opportunity to rebuild significant areas of the city. Public consultation identified enthusiasm to rebuild a sustainable city. A sustainable water sensitive city is one where development is constructed with the water environment in mind. Water sensitive urban design applies at all scales and is a holistic concept. In Christchurch larger-scale multi-value stormwater management solutions were incorporated into rapidly developed greenfield sites on the city’s outskirts and in satellite towns, as they had been pre-earthquake. Individual properties on greenfield sites and within the city, however, continued to be constructed without water sensitive features such as rainwater tanks or living roofs. This research uses semi-structured interviews, policy analysis, and findings from local and international studies to investigate the benefits of building-scale WSUD and the barriers that have resulted in their absence. Although several inter-related barriers became apparent, cost, commonly cited as a barrier to sustainable development in general, was strongly represented. However, it is argued that the issue is one of mindset rather than cost. Solutions are proposed, based on international and national experience, that will demonstrate the benefits of adopting water sensitive urban design principles including at the building scale, and thereby build public and political support. The research is timely - there is still much development to occur, and increasing pressures from urban densification, population growth and climate change to mitigate.
Following the devastation of the Canterbury earthquake sequence a unique opportunity exists to rebuild and restructure the city of Christchurch, ensuring that its infrastructure is constructed better than before and is innovative. By installing an integrated grid of modern sensor technologies into concrete structures during the rebuild of the Christchurch CBD, the aim is to develop a network of self-monitored ‘digital buildings’. A diverse range of data will be recorded, potentially including parameters such as concrete stresses, strains, thermal deformations, acoustics and the monitoring of corrosion of reinforcement bars. This procedure will allow an on-going complete assessment of the structure’s performance and service life, both before and after seismic activity. The data generated from the embedded and surface mounted sensors will be analysed to allow an innovative and real-time health monitoring solution where structural integrity is continuously known. This indication of building performance will allow the structure to alert owners, engineers and asset managers of developing problems prior to failure thresholds being reached. A range of potential sensor technologies for monitoring the performance of existing and newly constructed concrete buildings is discussed. A description of monitoring work conducted on existing buildings during the July 2013 Cook Strait earthquake sequence is included, along with details of current work that investigates the performance of sensing technologies for detecting crack formation in concrete specimens. The potential market for managing the real-time health of installed infrastructure is huge. Civil structures all over the world require regular visual inspections in order to determine their structural integrity. The information recorded during the Christchurch rebuild will generate crucial data sets that will be beneficial in understanding the behaviour of concrete over the complete life cycle of the structure, from construction through to operation and building repairs until the time of failure. VoR - Version of Record
It is well known that buildings constructed using unreinforced masonry (URM) are susceptible to damage from earthquake induced lateral forces that may result in partial or full building collapse. The 2010/2011 Canterbury earthquakes are the most recent New Zealand example of destructive earthquakes, which have drawn people's attention to the inherent seismic weaknesses of URM buildings and anchored masonry veneer systems in New Zealand. A brief review of the data collected following the 2010 Darfield earthquake and more comprehensive documentation of data that was collected following the 2011 Christchurch earthquake is presented, along with the findings from subsequent data interrogation. Large stocks of earthquake prone vintage URM buildings that remain in New Zealand and in other seismically active parts of the world result in the need for minimally invasive and cost effective seismic retrofit techniques. The principal objective of the doctoral research reported herein was to investigate the applicability of near surface mounted (NSM) carbon fibre reinforced polymer (CFRP) strips as a seismic improvement technique. A comprehensive experimental program consisting of 53 pull tests is presented and is used to assess the accuracy of existing FRP-to-masonry bond models, with a modified model being proposed. The strength characteristics of vintage clay brick URM wall panels from two existing URM buildings was established and used as a benchmark when manufacturing replica clay brick test assemblages. The applicability of using NSM CFRP strips as a retrofitting technique for improving the shear strength and the ductility capacity of multi-leaf URM walls constructed using solid clay brick masonry is investigated by varying CFRP reinforcement ratios. Lastly, an experimental program was undertaken to validate the proposed design methodology for improving the strength capacity of URM walls. The program involved testing full-scale walls in a laboratory setting and testing full-scale walls in-situ in existing vintage URM buildings. Experimental test results illustrated that the NSM CFRP technique is an effective method to seismically strengthen URM buildings.
Fatal earthquakes such as that which occurred in Christchurch on February 22nd 2011, can result in survivors having difficulties with cognitively processing the event, which may be the precursor to posttraumatic stress symptoms. Trauma related dissociation has been proposed to be a mechanism related to these cognitive processing difficulties. Most research focusing on information processing and dissociation post-trauma has conducted controlled analogue studies or has not focused solely on information processing and dissociation. There is also scant research on these constructs across therapy. In response to this gap in research, two studies were developed. An association was proposed between dissociation and information processing as demonstrated by an increase in conceptual processing and a reduction in dissociation. It was predicted that an improvement in these constructs would be related to a reduction in PTSD symptoms over therapy. Study1 applied a case-study design to 5 individuals who were attending therapy for post-traumatic stress disorder in response to the trauma they had experienced from the Christchurch earthquakes. Study 2 assessed information processing and dissociation (via self and observer report) in 20 individuals who had direct exposure to the effects of the earthquake. Earthquake information processing and dissociation were assessed as they were happening nearly two year’s post-quake using correlation analyses and hierarchical regressions. The hypotheses were partially confirmed, in that an increase in conceptual processing was not shown to be associated with a reduction in dissociation. However, an increase in conceptual processing was shown to be related to trauma symptom improvement particularly for re-experiencing symptoms. In addition, study 2 demonstrated a possible relationship between trait dissociation and arousal symptoms. These findings partially support the proposed role information processing and dissociation play in the recovery from PTSD. The findings suggest that trauma related difficulties should be assessed as early as possible to resolve issues related to a delay in symptom reporting.
Recent advances in timber design at the University of Canterbury have led to new structural systems that are appropriate for a wide range of building types, including multi-storey commercial office structures. These buildings are competitive with more traditional construction materials in terms of cost, sustainability and structural performance. This paper provides seismic design recommendations and analytical modelling approaches, appropriate for the seismic design of post-tensioned coupled timber wall systems. The models are based on existing seismic design theory for precast post-tensioned concrete, modified to more accurately account for elastic deformation of the timber wall systems and the influence of the floor system. Experimental test data from a two storey post-tensioned timber building, designed, constructed and tested at the University of Canterbury is used to validate the analytical models.
The Catholic Cathedral of the Blessed Sacrament is a category 1 listed heritage building constructed largely of unreinforced stone masonry, and was significantly damaged in the recent Canterbury earthquakes. The building experienced ground shaking in excess of its capacity leading to block failures and partial collapse of parts of the building, which left the building standing but still posing a significant hazard. In this paper we discuss the approach to securing the building, and the interaction of the structural, heritage and safety demands involved in a dynamic seismic risk environment. We briefly cover the types of failures observed and the behaviour of the structure, and investigate the performance of both strengthened and un-strengthened parts of the building. Seismic strengthening options are investigated at a conceptual level. We draw conclusions as to how the building performed in the earthquakes, comment on the effectiveness of the strengthening and securing work and discuss the potential seismic strengthening methods.
This paper explores the scope of small-scale radio to create an auditory geography of place. It focuses on the short term art radio project The Stadium Broadcast, which was staged in November 2014 in an earthquake-damaged sports stadium in Christchurch, New Zealand. Thousands of buildings and homes in Christchurch have been demolished since the Februrary 22, 2011 earthquake, and while Lancaster Park sports stadium is still standing, it has been unused since that date and its future remains uncertain. The Stadium Broadcast constructed a radio memorial to the Park’s 130 year history through archival recordings, the memories of local people, observation of its current state, and a performed site-specificity. The Stadium Broadcast reflected on the spatiality of radio sounds and transmissions, memory, post-disaster transitionality, and the im-permanence of place.
This article explores the scope of small-scale radio to create an auditory geography of place. It focuses on the short-term art radio project The Stadium Broadcast, which was staged in November 2014 in an earthquake-damaged sports stadium in Christchurch, New Zealand. Thousands of buildings and homes in Christchurch have been demolished since the February 22, 2011, earthquake, and by the time of the broadcast the stadium at Lancaster Park had been unused for three years and nine months, and its future was uncertain. The Stadium Broadcast constructed a radio memorial to the Park’s 130-year history through archival recordings, the memories of local people, observation of its current state, and a performed site-specificity. The Stadium Broadcast reflected on the spatiality of radio sounds and transmissions, memory, postdisaster transitionality, and the impermanence of place.
Collective identity construction in organisations engaged in an inter-organisational collaboration (IOC), especially temporary IOCs set up in disaster situations, has received scant attention in the organisational studies literature yet collective identity is considered to be important in fostering effective IOC operations. This doctoral study was designed to add to our understanding about how collective identity is constituted throughout the entire lifespan of a particular temporary coopetitive (i.e., simultaneously collaborative and competitive) IOC formed in a post-disaster environment. To achieve this purpose, a qualitative case study of the Stronger Christchurch Infrastructure Rebuild Team (SCIRT), a time-bound coopetition formed to repair the horizontal infrastructure in Christchurch, New Zealand after the devastating 2011 Canterbury earthquakes, was undertaken. Using data from semi-structured interviews, field observations, and organisational documents and other artefacts, an inductive analytic method was employed to explore how internal stakeholders engaged with and co- constructed a collective SCIRT identity and reconciled this with their home organization identity. The analysis revealed that the SCIRT collective identity was an ongoing process, involving the interweaving of social, temporal, material and geospatial dimensions constructed through intersecting cycles of senior managers’ sensegiving and employees’ sensemaking across SCIRT’s five and a half years of existence. Senior management deliberately undertook identity work campaigns that used organisational rituals, artefacts, and spatial design to disseminate and encourage a sense of “we are all SCIRT”. However, there was no common sense of “we-ness”. Identification with SCIRT was experienced differently among different groups of employees and across time. Employees’ differing senses of collective identity were accounted for by their past, present, and anticipated future relationships with their home organisation, and also (re)shaped by the geosocial environments in which they worked. The study supports previous research claiming that collective identity is a process of recursive sensegiving and sensemaking between senior managers and employees. However, it extends the literature by revealing the imbricated nature of collective identity, how members’ sense of “who we are” can change across the entire lifetime of a temporary IOC, and how sociomateriality, temporality, and geosocial effects strongly intervene in employees’ emerging senses of collective identity. Moreover, the study demonstrates how the ongoing identity work can be embedded in a time-space frame that further accentuates the influence of temporality, especially the anticipated future, organisational rituals, artefacts, and the geosocial environment. The study’s primary contribution to theory is a processual model of collective identity that applies specifically to a temporary IOC involving coopetition. In doing so, it represents a more finely nuanced and situational model than existing models. At a practical level, this model suggests that managers need to appreciate that organisational artefacts, rituals, and the prevailing organisational geosocial environment are inextricably linked in processes that can be manipulated to enhance the construction of collective identity.
An as-built reinforced concrete (RC) frame building designed and constructed according to pre-1970s code design construction practice has been recently tested on the shake table at the University of Canterbury. The specimen, 1/2.5 scaled version of the original prototype, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. Following the benchmark test, a retrofit intervention has been proposed to rehabilitate the tested specimen. In this paper, detailed information on the assessment and design of the seismic retrofit procedure using GFRP (glass fibre reinforced polymer) materials is given for the whole frame. Hierarchy of strength and sequence of events (damage mechanisms) in the panel zone region are evaluated using a moment-axial load (M-N) interaction performance domain, according to a performance-based retrofit philosophy. Specific limit states or design objectives are targeted with attention given to both strength and deformation limits. In addition, an innovative retrofit solution using FRP anchor dowels for the corner beam-column joints with slabs is proposed. Finally, in order to provide a practical tool for engineering practice, the retrofit procedure is provided in a step-by step flowchart fashion.
This research investigates the validation of simulated ground motions on complex structural systems. In this study, the seismic responses of two buildings are compared when they are subjected to as-recorded ground motions and simulated ones. The buildings have been designed based on New Zealand codes and physically constructed in Christchurch, New Zealand. The recorded ground motions are selected from 40 stations database of the historical 22 Feb. 2011 Christchurch earthquake. The Graves and Pitarka (2015) methodology is used to generate the simulated ground motions. The geometric mean of maximum inter-story drift and peak floor acceleration are selected as the main seismic responses. Also, the variation of these parameters due to record to record variability are investigated. Moreover, statistical hypothesis testing is used to investigate the similarity of results between observed and simulated ground motions. The results indicate a general agreement between the peak floor acceleration calculated by simulated and recorded ground motions for two buildings. While according to the hypothesis tests result, the difference in drift can be significant for the building with a shorter period. The results will help engineers and researchers to use or revise the procedure by using simulated ground motions for obtaining seismic responses.
Validating dynamic responses of engineered systems subjected to simulated ground motions is essential in scrutinising the applicability of simulated ground motions for engineering demand analyses. This paper compares the responses of two 3D building models subjected to recorded and simulated ground motions scaled to the NZS1170.5 design response spectrum, in order to evaluate the applicability of simulated ground motions for use in conventional engineering practice in New Zealand. The buildings were designed according to the NZS1170.5 and physically constructed in Christchurch prior to the 2010-2011 Canterbury earthquakes. 40 recorded ground motions from the 22 February 2011 Christchurch earthquake, along with the simulated ground motions for this event from Razafindrakoto et al. (2018) are considered. The seismic responses of the structures are principally quantified via the peak floor acceleration and maximum inter-storey drift ratio. Overall, the results indicate a general agreement in seismic demands obtained using the recorded and simulated ensembles of ground motions and provide further evidence that simulated ground motions using state-of-the-art methods can be used in code-based structural performance assessments inplace of, or in combination with, ensembles of recorded ground motions.
Improving community resilience requires a way of thinking about the nature of a community. Two complementary aspects are proposed: the flows connecting the community with its surrounding environment and the resources the community needs for its ongoing life. The body of necessary resources is complex, with many interactions between its elements. A systems approach is required to understand the issues adequately. Community resilience is discussed in general terms together with strategies for improving it. The ideas are then illustrated and amplified by an extended case study addressing means of improving the resilience of a community on the West Coast of New Zealand to natural disasters. The case study is in two phases. The first relies on a mix of on-the-ground observations and constructed scenarios to provide recommendations for enhancing community resilience, while the second complements the first by developing a set of general lessons and issues to be addressed from observations of the Christchurch earthquakes of 2010 and 2011.
The 2010/2011 Canterbury earthquakes have provided a unique opportunity to investigate the seismic performance of both traditional and modern buildings constructed in New Zealand. It is critical that the observed performance is examined and compared against the expected levels of performance that are outlined by the Building Code and Design Standards. In particular, in recent years there has been a significant amount of research into the seismic behaviour of precast concrete floor systems and the robustness of the support connections as a building deforms during an earthquake. An investigation of precast concrete floor systems in Christchurch has been undertaken to assess both the performance of traditional and current design practice. The observed performance for each type of precast floor unit was collated from a number of post-earthquake recognisance activities and compared against the expected performance determined for previous experimental testing and analysis. Possible reasons for both the observed damage, and in some cases the lack of damage, were identified. This critical review of precast concrete floor systems will assist in determining the success of current design practice as well as identify any areas that require further research and/or changes to design standards.
The Catholic Cathedral is classified as a category 1 listed heritage building constructed largely of unreinforced stone masonry, and was significantly damaged in the recent Canterbury earthquakes of 2010 and 2011. In the 2010 event the building presented slight to moderta damage, meanwhile in the 2011 one experienced ground shaking in excess of its capacity leading to block failures and partial collapse of parts of the building, which left the building standing but still posing a significant hazard. In this paper we discuss the approach to develop the earthquake analysis of the building by 3D numerical simulations, and the results are compared/calibrated with the observed damage of the 2010 earthquake. Very accurate records were obtained during both earthquakes due to a record station located least than 80 m of distance from the building and used in the simulations. Moreover it is included in the model the soil structure interaction because it was observed that the ground and foundation played an important role on the seismic behavior of the structure. A very good agreement was found between the real observed damage and the nonlinear dynamic simulations described trough inelastic deformation (cracking) and building´s performance.
Following a major earthquake event, essential public amenities such as medical facilities and transport networks need to remain functional - not only to fulfil their ongoing role in serving the community but also to cope with the added and immediate demand of a population affected by a natural disaster. Furthermore, the economic implications of wide spread damage to housing and commercial facilities should not be discounted. A shift in design approach is required that is consistent with current trends towards performance based building design. The present aim is to achieve seismic energy dissipation during the earthquake event, without the aftermath of damage to structural elements, whilst maintaining design economies. Structures permitted to rock on their foundations and provide recoverable rotations at the beam-column interfaces offer significant advantages over those using conventional ductile detailing. A jointed construction philosophy can be applied whereby structural elements are connected with unbonded prestressing tendons. Supplemental damping is provided by replaceable flexural steel components designed to deform inelastically. For this research a multi-storey test building of one quarter scale has been constructed and tested on an earthquake simulator at the University of Canterbury. A computer model has been developed and a set ofpreliminary design procedures proposed.
This paper presents preliminary results of an experimental campaign on three beam-column joint subassemblies extracted from a 22-storey reinforced concrete frame building constructed in late 1980s at the Christchurch’s Central Business District (CBD) area, damaged and demolished after the 2010-2011 Canterbury earthquakes sequence (CES). The building was designed following capacity design principles. Column sway (i.e., soft storey) mechanisms were avoided, and the beams were provided with plastic hinge relocation details at both beam-ends, aiming at developing plastic hinges away from the column faces. The specimens were tested under quasi-static cyclic displacement controlled lateral loading. One of the specimens, showing no visible residual cracks was cyclically tested in its as-is condition. The other two specimens which showed residual cracks varying between hairline and 1.0mm in width, were subjected to cyclic loading to simulate cracking patterns consistent with what can be considered moderate damage. The cracked specimens were then repaired with an epoxy injection technique and subsequently retested until reaching failure. The epoxy injection techniques demonstrated to be quite efficient in partly, although not fully, restoring the energy dissipation capacities of the damaged specimens at all beam rotation levels. The stiffness was partly restored within the elastic range and almost fully restored after the onset of nonlinear behaviour.
One of the great challenges facing human systems today is how to prepare for, manage, and adapt successfully to the profound and rapid changes wreaked by disasters. Wellington, New Zealand, is a capital city at significant risk of devastating earthquake and tsunami, potentially requiring mass evacuations with little or short notice. Subsequent hardship and suffering due to widespread property damage and infrastructure failure could cause large areas of the Wellington Region to become uninhabitable for weeks to months. Previous research has shown that positive health and well-being are associated with disaster-resilient outcomes. Preventing adverse outcomes before disaster strikes, through developing strengths-based skill sets in health-protective attitudes and behaviours, is increasingly advocated in disaster research, practise, and management. This study hypothesised that well-being constructs involving an affective heuristic play vital roles in pathways to resilience as proximal determinants of health-protective behaviours. Specifically, this study examined the importance of health-related quality of life and subjective well-being in motivating evacuation preparedness, measured in a community sample (n=695) drawn from the general adult population of Wellington’s isolated eastern suburbs. Using a quantitative epidemiological approach, the study measured the prevalence of key quality of life indicators (physical and mental health, emotional well-being or “Sense of Coherence”, spiritual well-being, social well-being, and life satisfaction) using validated psychometric scales; analysed the strengths of association between these indicators and the level of evacuation preparedness at categorical and continuous levels of measurement; and tested the predictive power of the model to explain the variance in evacuation preparedness activity. This is the first study known to examine multi-dimensional positive health and global well-being as resilient processes for engaging in evacuation preparedness behaviour. A cross-sectional study design and quantitative survey were used to collect self-report data on the study variables; a postal questionnaire was fielded between November 2008 and March 2009 to a sampling frame developed through multi-stage cluster randomisation. The survey response rate was 28.5%, yielding a margin of error of +/- 3.8% with 95% confidence and 80% statistical power to detect a true correlation coefficient of 0.11 or greater. In addition to the primary study variables, data were collected on demographic and ancillary variables relating to contextual factors in the physical environment (risk perception of physical and personal vulnerability to disaster) and the social environment (through the construct of self-determination), and other measures of disaster preparedness. These data are reserved for future analyses. Results of correlational and regression analyses for the primary study variables show that Wellingtonians are highly individualistic in how their well-being influences their preparedness, and a majority are taking inadequate action to build their resilience to future disaster from earthquake- or tsunami-triggered evacuation. At a population level, the conceptual multi-dimensional model of health-related quality of life and global well-being tested in this study shows a positive association with evacuation preparedness at statistically significant levels. However, it must be emphasised that the strength of this relationship is weak, accounting for only 5-7% of the variability in evacuation preparedness. No single dimension of health-related quality of life or well-being stands out as a strong predictor of preparedness. The strongest associations for preparedness are in a positive direction for spiritual well-being, emotional well-being, and life satisfaction; all involve a sense of existential meaningfulness. Spiritual well-being is the only quality of life variable making a statistically significant unique contribution to explaining the variance observed in the regression models. Physical health status is weakly associated with preparedness in a negative direction at a continuous level of measurement. No association was found at statistically significant levels for mental health status and social well-being. These findings indicate that engaging in evacuation preparedness is a very complex, holistic, yet individualised decision-making process, and likely involves highly subjective considerations for what is personally relevant. Gender is not a factor. Those 18-24 years of age are least likely to prepare and evacuation preparedness increases with age. Multidimensional health and global well-being are important constructs to consider in disaster resilience for both pre-event and post-event timeframes. This work indicates a need for promoting self-management of risk and building resilience by incorporating a sense of personal meaning and importance into preparedness actions, and for future research into further understanding preparedness motivations.
An UnReinforced clay brick Masonry (URM) chimney is composed of a cantilever URM appendage above a roofline and is considered one of the most earthquake prone non-structural compo¬nents within vintage URM and timber-framed buildings. Observations from past earthquakes including the 1992 Big Bear City earthquake, 1994 Northridge earthquake, 2001 Nisqually earthquake, 2010/2011 Canterbury earthquakes, 2012 Northern Italy earthquakes, and 2014 South Napa earthquake served repeatedly as a reminder of the hazard induced by URM chimneys. The observed failure types included several cases where the adopted retrofit techniques were not adequate to effectively secure chimneys dur¬ing the earthquake. Data collected during the 2010/2011 post-earthquake building assessments in Christchurch and insur¬ance claims are reported herein. Five full-scale solid clay brick URM chimneys which replicated the most encountered geometrical and construction characteristics were subjected to shake table testing. Two chim¬ney samples were representative of the as-built conditions, while three samples were retrofitted using two different configurations of Near-Surface-Mounted (NSM) Carbon-Fibre-Reinforced-Polymer (CFRP) strips and post-tensioning techniques. The adopted securing techniques allowed an increase in seismic acceleration capacity of more than five times for chimneys constructed with ultra-weak mortar and more than twice for chimneys built with weak mortar. http://www.16ibmac.com/
Seismic behaviour of typical unreinforced masonry (URM) brick houses, that were common in early last century in New Zealand and still common in many developing countries, is experimentally investigated at University of Canterbury, New Zealand in this research. A one halfscale model URM house is constructed and tested under earthquake ground motions on a shaking table. The model structure with aspect ratio of 1.5:1 in plan was initially tested in the longitudinal direction for several earthquakes with peak ground acceleration (PGA) up to 0.5g. Toppling of end gables (above the eaves line) and minor to moderate cracking around window and door piers was observed in this phase. The structure was then rotated 90º and tested in the transverse (short) direction for ground motions with PGA up to 0.8g. Partial out-of-plane failure of the face loaded walls in the second storey and global rocking of the model was observed in this phase. A finite element analysis and a mechanism analysis are conducted to assess the dynamic properties and lateral strength of the model house. Seismic fragility function of URM houses is developed based on the experimental results. Damping at different phases of the response is estimated using an amplitude dependent equivalent viscous damping model. Financial risk of similar URM houses is then estimated in term of expected annual loss (EAL) following a probabilistic financial risk assessment framework. Risks posed by different levels of damage and by earthquakes of different frequencies are then examined.
The 2010-2011 Christchurch earthquakes generated damage in several Reinforced Concrete (RC) buildings, which had RC walls as the principal resistant element against earthquake demand. Despite the agreement between structural engineers and researchers in an overall successfully performance there was a lack of knowledge about the behaviour of the damaged structures, and even deeper about a repaired structure, which triggers arguments between different parties that remains up to these days. Then, it is necessary to understand the capacity of the buildings after the earthquake and see how simple repairs techniques improve the building performance. This study will assess the residual capacity of ductile slender RC walls according to current standards in New Zealand, NZS 3101.1 2006 A3. First, a Repaired RC walls Database is created trying to gather previous studies and to evaluate them with existing international guidelines. Then, an archetype building is designed, and the wall is extracted and scaled. Four half-scale walls were designed and will be constructed and tested at the Structures Testing Laboratory at The University of Auckland. The overall dimensions are 3 [m] height, 2 [m] length and 0.175 [m] thick. All four walls will be identical, with differences in the loading protocol and the presence or absence of a repair technique. Results are going to be useful to assess the residual capacity of a damaged wall compare to the original behaviour and also the repaired capacity of walls with simpler repair techniques. The expected behaviour is focussed on big changes in stiffness, more evident than in previously tested RC beams found in the literature.
Recent major earthquakes such as Northridge 1994 and Izmit Kocaeli 1999 highlighted the poor performance of existing buildings constructed prior to the early 1970’s. Low lateral seismic design coefficients and the adopted “working stress design” methodology (essentially an elastic design) lacked any inelastic design considerations, thus leading to inadequate detailing. Insufficient development lengths, lapping within potential plastic hinge regions, lack, or total absence of joint transverse reinforcement, and the use of plain round reinforcement and hooked end anchorages were common throughout the structure. The behaviour is generally dominated by brittle local failure mechanisms (e.g. joint or element shear failures) as well as possible soft-storey mechanisms at a global level. Amongst several possible retrofit interventions, a typical solution is to provide the structure with additional structural walls i.e. external buttressing or column in-fills. Extensive developments on precast, post-tensioned, dissipative systems have shown promise for the use of rocking wall systems to retrofit existing poorly detailed frame structures. In this contribution, the feasibility of such a retrofit intervention is investigated. A displacement-based retrofit procedure is developed and proposed, based on targeting pre-defined performance criteria, such as joint shear and/or column curvature deformation limits. A design example, using the proposed retrofit strategy on a prototype frame is presented. A brief overview on experimental work ongoing at the University of Canterbury investigating the dynamic response of advanced rocking walls for retrofit purposes will be provided.
Study region: Christchurch, New Zealand. Study focus: Low-lying coastal cities worldwide are vulnerable to shallow groundwater salinization caused by saltwater intrusion and anthropogenic activities. Shallow groundwater salinization can have cascading negative impacts on municipal assets, but this is rarely considered compared to impacts of salinization on water supply. Here, shallow groundwater salinity was sampled at high spatial resolution (1.3 piezometer/km2 ), then mapped and spatially interpolated. This was possible due to a uniquely extensive set of shallow piezometers installed in response to the 2010–11 Canterbury Earthquake Sequence to assess liquefaction risk. The municipal assets located within the brackish groundwater areas were highlighted. New hydrological insights for the region: Brackish groundwater areas were centred on a spit of coastal sand dunes and inside the meander of a tidal river with poorly drained soils. The municipal assets located within these areas include: (i) wastewater and stormwater pipes constructed from steel-reinforced concrete, which, if damaged, are vulnerable to premature failure when exposed to chloride underwater, and (ii) 41 parks and reserves totalling 236 ha, within which salt-intolerant groundwater-dependent species are at risk. This research highlights the importance of determining areas of saline shallow groundwater in low-lying coastal urban settings and the co-located municipal assets to allow the prioritisation of sites for future monitoring and management.
Reconnaissance reports have highlighted the poor performance of non-ductile reinforced concrete buildings during the 2010-11 Canterbury earthquakes. These buildings are widely expected to result in significant losses under future earthquakes due to their seismic vulnerability and prevalence in densely populated urban areas. Wellington, for example, contains more than 70 pre-1970s multi-storey reinforced concrete buildings, ranging in height from 5 to 18 storeys. This study seeks to characterise the seismic performance and evaluate the likely failure modes of a typical pre-1970s reinforced concrete building in Wellington, by conducting advanced numerical simulations to evaluate its 3D nonlinear dynamic response. A representative 9-storey office building constructed in 1951 is chosen for this study and modelled in the finite element analysis programme DIANA, using a previously developed and validated approach to predict the failure modes of doubly reinforced walls with confined boundary regions. The structure consists of long walls and robust framing elements resulting in a stiff lateral load resisting system. Barbell-shaped walls are flanked by stiff columns with sufficient transverse reinforcement to serve as boundary regions. Curved shell elements are used to model the walls and their boundary columns, for which the steel reinforcement is explicitly modelled. Line elements are used to model the frame elements. The steel reinforcement in each member is explicitly modelled. The floor slabs are modelled using elastic shell elements. The model is analysed under short and long duration ground motions selected to match site specific targets in Wellington at the DBE and MCE intensity levels. The observed response of the building including drift profiles at each intesity level, strain localization effects around wall openings, and the influence of bidirectional loading are discussed.
Seismically vulnerable buildings constitute a major problem for the safety of human beings. In many parts of the world, reinforced concrete (RC) frame buildings designed and constructed with substandard detailing, no consideration of capacity design principles, and improper or no inclusion of the seismic actions, have been identified. Amongst those vulnerable building, one particular typology representative of the construction practice of the years previous to the 1970’s, that most likely represents the worst case scenario, has been widely investigated in the past. The deficiencies of that building typology are related to non-ductile detailing in beam column joints such as the use of plain round bars, the lack of stirrups inside the joint around the longitudinal reinforcement of the column, the use of 180° end hooks in the beams, the use of lap splices in potential ‘plastic hinge’ regions, and substandard quality of the materials. That type of detailing and the lack of a capacity design philosophy create a very fragile fuse in the structure where brittle inelastic behaviour is expected to occur, which is the panel zone region of exterior beam column joints. The non-ductile typology described above was extensively investigated at the University of Canterbury in the context of the project ‘Retrofit Solutions for New Zealand Multi-Storey Buildings’ (2004-2011), founded by the ‘Foundation for Research, Science and Technology’ Tūāpapa Rangahau Pūtaiao. The experimental campaign prior to the research carried out by the author consisted of quasi-static tests of beam column joint subassemblies subjected to lateral loading regime, with constant and varying axial load in the column. Most of those specimens were representative of a plane 2D frame (knee joint), while others represented a portion of a space 3D frame (corner joints), and only few of them had a floor slab, transverse beams, and lap splices. Using those experiments, several feasible, cost-effective, and non-invasive retrofit techniques were developed, improved, and refined. Nevertheless, the slow motion nature of those experiments did not take into account the dynamical component inherent to earthquake related problems. Amongst the set of techniques investigated, the use of FRP layers for strengthening beam column joints is of particular interest due to its versatility and the momentum that its use has gained in the current state of the practice. That particular retrofit technique was previously used to develop a strengthening scheme suitable for plane 2D and space 3D corner beam column joints, but lacking of floor slabs. In addition, a similar scheme was not developed for exterior joints of internal frames, referred here as ‘cruciform’. In this research a 2/5 scale RC frame model building comprising of two frames in parallel (external and internal) joined together by means of floor slabs and transverse beams, with non-ductile characteristics identical to those of the specimens investigated previously by others, and also including lap splices, was developed. In order to investigate the dynamic response of that building, a series of shake table tests with different ground motions were performed. After the first series of tests, the specimen was modified by connecting the spliced reinforcement in the columns in order to capture a different failure mode. Ground motions recorded during seismic events that occurred during the initial period of the experimental campaign (2010) were used in the subsequent experiments. The hierarchy of strengths and sequence of events in the panel zone region were evaluated in an extended version of the bending moment-axial load (M-N) performance domain developed by others. That extension was required due to the asymmetry in the beam cross section introduced by the floor slab. In addition, the effect of the torsion resistance provided by the spandrel (transverse beam) was included. In order to upgrade the brittle and unstable performance of the as-built/repaired specimen, a practical and suitable ad-hoc FRP retrofit intervention was developed, following a partial retrofit strategy that aimed to strengthen exterior beam column joints only (corner and cruciform). The ability of the new FRP scheme to revert the sequence of events in the panel zone region was evaluated using the extended version of the M-N performance domain as well as the guidelines for strengthening plane joints developed by others. Weakening of the floor slab in a novel configuration was also incorporated with the purpose of reducing the flexural capacity of the beam under negative bending moment (slab in tension), enabling the damage relocation from the joint into the beam. The efficacy of the developed retrofit intervention in upgrading the seismic performance of the as-built specimen was investigated using shake table tests with the input motions used in the experiments of the as-built/repaired specimen. Numerical work aimed to predict the response of the model building during the most relevant shake table tests was carried out. By using a simple numerical model with concentrated plasticity elements constructed in Ruaumoko2D, the results of blind and post-experimental predictions of the response of the specimen were addressed. Differences in the predicted response of the building using the nominal and the actual recorded motions of the shake table were investigated. The dependence of the accuracy of the numerical predictions on the assumed values of the parameters that control the hysteresis rules of key structural members was reviewed. During the execution of the experimental campaign part of this thesis, two major earthquakes affected the central part of Chile (27 of February 2010 Maule earthquake) and the Canterbury region in New Zealand (22 February 2011 Canterbury earthquake), respectively. As the author had the opportunity to experience those events and investigate their consequences in structures, the observations related to non-ductile detailing and drawbacks in the state of the practice related to reinforced concrete walls was also addressed in this research, resulting in preliminary recommendations for the refinement of current seismic code provisions and assessment guidelines. The investigations of the ground motions recorded during those and other earthquakes were used to review the procedures related to the input motions used for nonlinear dynamic analysis of buildings as required by most of the current code provisions. Inelastic displacement spectra were constructed using ground motions recorded during the earthquakes mentioned above, in order to investigate the adequacy of modification factors used to obtain reduced design spectra from elastic counterparts. Finally a simplified assessment procedure for RC walls that incorporates capacity compatible spectral demands is proposed.
