© 2017 The Royal Society of New Zealand. This paper discusses simulated ground motion intensity, and its underlying modelling assumptions, for great earthquakes on the Alpine Fault. The simulations utilise the latest understanding of wave propagation physics, kinematic earthquake rupture descriptions and the three-dimensional nature of the Earth's crust in the South Island of New Zealand. The effect of hypocentre location is explicitly examined, which is found to lead to significant differences in ground motion intensities (quantified in the form of peak ground velocity, PGV) over the northern half and southwest of the South Island. Comparison with previously adopted empirical ground motion models also illustrates that the simulations, which explicitly model rupture directivity and basin-generated surface waves, lead to notably larger PGV amplitudes than the empirical predictions in the northern half of the South Island and Canterbury. The simulations performed in this paper have been adopted, as one possible ground motion prediction, in the ‘Project AF8’ Civil Defence Emergency Management exercise scenario. The similarity of the modelled ground motion features with those observed in recent worldwide earthquakes as well as similar simulations in other regions, and the notably higher simulated amplitudes than those from empirical predictions, may warrant a re-examination of regional impact assessments for major Alpine Fault earthquakes.
The coordination of actors has been a major focus for much of the research in the disaster relief humanitarian logistics discipline. While much of this literature focuses on the initial response phase, little has been written on the longer term recover phase. As the response phase transitions into the longer term recover phase the number and types of actors change from predominantly disaster relief NGOs to more commercial entities we argue that humanitarian values should still be part of the rebuild phase. It has been noted that humanitarian actors both cooperate and compete at the same time (Balcik, Beamon, Krejci, Muramatsu and Ramirez, 2010), in a form of behavior that can be described as ‘co-opetition’ (Nalebuff and Brandenburger, 1996). We use a case study approach to examine an organizational model used to coordinate civil and commercial actors for the rebuild of the civil infrastructure for Christchurch, New Zealand following a series of devastating earthquakes in 2010/11. For the rebuild phase we argue that ‘co-opetition’ is a key behaviour that allows the blending of humanitarian and commercial values to help communities rebuild to a new normal. While at this early stage our contribution is limited, we eventually hope to fully elaborate on an organisational model that has been created specifically for the tight coordination of commercial actors and its relevance to the rebuild phase of a disaster. Examining the behaviour of co-opetition and the structures that incentivise this behaviour offers insights for the humanitarian logistic field.
The Porters Pass fault (PPF) is a prominent element of the Porters Pass-Amberley Fault Zone (PPAFZ) which forms a broad zone of active earth deformation ca 100 km long, 60-90 km west and north of Christchurch. For a distance of ca 40 km the PPF is defined by a series of discontinuous Holocene active traces between the Rakaia and Waimakariri Rivers. The amount of slip/event and the timing of paleoearthquakes are crucial components needed to estimate the earthquake potential of a fault. Movement was assumed to be, coseismic and was quantified by measuring displaced geomorphic features using either tape measure or surveying equipment. Clustering of offset data suggests that four to five earthquakes occurred on the PPF during the Holocene and these range between ca 5-7 m/event. Timing information was obtained from four trenches excavated across the fault and an auger adjacent to the fault. Organic samples from these sites were radiocarbon dated and used in conjunction with data from previous studies to identify the occurrence of at least four earthquakes at 8500 ± 200, 5300 ± 700, 2500 ± 200 and 1000 ± 100 years B.P. Evidence suggests that an additional event is also possible at 6200 ± 500 years B.P. The ~1000, 5300 and 6200 years B.P. paleoearthquakes were previously unrecognised, while the 500 year event previously inferred from rock-avalanche data has been discarded. The present data set produces recurrence intervals of ~2000-2500 years for the Holocene. The identification of only one Holocene PPF rupture to the west of Red Lakes indicates the presence of a segment boundary that prevents the propagation of rupture beyond this point. This is consistent with displacement data and results in slip rates of 0.5-0.7 mm/yr and 2.5-3.4 mm/yr to the west and east of Red Lakes respectively. It is possible that the nearby extensional Red Hill Fault influences PPF rupture propagation. The combination of geometric, slip rate and timing data has enabled the magnitude of prehistoric earthquakes on the PPF to be estimated. These magnitudes range from an average of between 6.9 for a fault rupture from Waimakariri River to Red Lakes, to a maximum of 7.4 that ruptures the entire length of the PPAFZ, including the full length of the PPF. These estimates are approximately consistent with previous magnitude estimates along the full length of the PPAFZ of between 7.0 and 7.5.
The recent instances of seismic activity in Canterbury (2010/11) and Kaikōura (2016) in New Zealand have exposed an unexpected level of damage to non-structural components, such as buried pipelines and building envelope systems. The cost of broken buried infrastructure, such as pipeline systems, to the Christchurch Council was excessive, as was the cost of repairing building envelopes to building owners in both Christchurch and Wellington (due to the Kaikōura earthquake), which indicates there are problems with compliance pathways for both of these systems. Councils rely on product testing and robust engineering design practices to provide compliance certification on the suitability of product systems, while asset and building owners rely on the compliance as proof of an acceptable design. In addition, forensic engineers and lifeline analysts rely on the same product testing and design techniques to analyse earthquake-related failures or predict future outcomes pre-earthquake, respectively. The aim of this research was to record the actual field-observed damage from the Canterbury and Kaikōura earthquakes of seismic damage to buried pipeline and building envelope systems, develop suitable testing protocols to be able to test the systems’ seismic resilience, and produce prediction design tools that deliver results that reflect the collected field observations with better accuracy than the present tools used by forensic engineers and lifeline analysts. The main research chapters of this thesis comprise of four publications that describe the gathering of seismic damage to pipes (Publication 1 of 4) and building envelopes (Publication 2 of 4). Experimental testing and the development of prediction design tools for both systems are described in Publications 3 and 4. The field observation (discussed in Publication 1 of 4) revealed that segmented pipe joints, such as those used in thick-walled PVC pipes, were particularly unsatisfactory with respect to the joint’s seismic resilience capabilities. Once the joint was damaged, silt and other deleterious material were able to penetrate the pipeline, causing blockages and the shutdown of key infrastructure services. At present, the governing Standards for PVC pipes are AS/NZS 1477 (pressure systems) and AS/NZS 1260 (gravity systems), which do not include a protocol for evaluating the PVC pipes for joint seismic resilience. Testing methodologies were designed to test a PVC pipe joint under various different simultaneously applied axial and transverse loads (discussed in Publication 3 of 4). The goal of the laboratory experiment was to establish an easy to apply testing protocol that could fill the void in the mentioned standards and produce boundary data that could be used to develop a design tool that could predict the observed failures given site-specific conditions surrounding the pipe. A tremendous amount of building envelope glazing system damage was recorded in the CBDs of both Christchurch and Wellington, which included gasket dislodgement, cracked glazing, and dislodged glazing. The observational research (Publication 2 of 4) concluded that the glazing systems were a good indication of building envelope damage as the glazing had consistent breaking characteristics, like a ballistic fuse used in forensic blast analysis. The compliance testing protocol recognised in the New Zealand Building Code, Verification Method E2/VM1, relies on the testing method from the Standard AS/NZS 4284 and stipulates the inclusion of typical penetrations, such as glazing systems, to be included in the test specimen. Some of the building envelope systems that failed in the recent New Zealand earthquakes were assessed with glazing systems using either the AS/NZS 4284 or E2/VM1 methods and still failed unexpectedly, which suggests that improvements to the testing protocols are required. An experiment was designed to mimic the observed earthquake damage using bi-directional loading (discussed in Publication 4 of 4) and to identify improvements to the current testing protocol. In a similar way to pipes, the observational and test data was then used to develop a design prediction tool. For both pipes (Publication 3 of 4) and glazing systems (Publication 4 of 4), experimentation suggests that modifying the existing testing Standards would yield more realistic earthquake damage results. The research indicates that including a specific joint testing regime for pipes and positioning the glazing system in a specific location in the specimen would improve the relevant Standards with respect to seismic resilience of these systems. Improving seismic resilience in pipe joints and glazing systems would improve existing Council compliance pathways, which would potentially reduce the liability of damage claims against the government after an earthquake event. The developed design prediction tool, for both pipe and glazing systems, uses local data specific to the system being scrutinised, such as local geology, dimensional characteristics of the system, actual or predicted peak ground accelerations (both vertically and horizontally) and results of product-specific bi-directional testing. The design prediction tools would improve the accuracy of existing techniques used by forensic engineers examining the cause of failure after an earthquake and for lifeline analysts examining predictive earthquake damage scenarios.
The 2010 Darfield earthquake is the largest earthquake on record to have occurred within 40 km of a major city and not cause any fatalities. In this paper the authors have reflected on their experiences in Christchurch following the earthquake with a view to what worked, what didn’t, and what lessons can be learned from this for the benefit of Australian earthquake preparedness. Owing to the fact that most of the observed building damage occurred in Unreinforced Masonry (URM) construction, this paper focuses in particular on the authors’ experience conducting rapid building damage assessment during the first 72 hours following the earthquake and more detailed examination of the performance of unreinforced masonry buildings with and without seismic retrofit interventions.
Despite the relatively low seismicity, a large earthquake in the Waikato region is expected to have a high impact, when the fourth-largest regional population and economy and the high density critical infrastructure systems in this region are considered. Furthermore, Waikato has a deep soft sedimentary basin, which increases the regional seismic hazard due to trapping and amplification of seismic waves and generation of localized surface waves within the basin. This phenomenon is known as the “Basin Effect”, and has been attributed to the increased damage in several historic earthquakes, including the 2010-2011 Canterbury earthquakes. In order to quantitatively model the basin response and improve the understanding of regional seismic hazard, geophysical methods will be used to develop shear wave velocity profiles across the Waikato basin. Active surface wave methods involve the deployment of linear arrays of geophones to record the surface waves generated by a sledge hammer. Passive surface wave methods involve the deployment of two-dimensional seismometer arrays to record ambient vibrations. At each site, the planned testing includes one active test and two to four passive arrays. The obtained data are processed to develop dispersion curves, which describe surface wave propagation velocity as a function of frequency (or wavelength). Dispersion curves are then inverted using the Geopsy software package to develop a suite of shear wave velocity profiles. Currently, more than ten sites in Waikato are under consideration for this project. This poster presents the preliminary results from the two sites that have been tested. The shear wave velocity profiles from all sites will be used to produce a 3D velocity model for the Waikato basin, a part of QuakeCoRE flagship programme 1.
Following the 2010-2011 Canterbury (New Zealand) earthquake sequence, lightly reinforced wall structures in the Christchurch central business district were observed to form undesirable crack patterns in the plastic hinge region, while yield penetration either side of cracks and into development zones was less than predicted using empirical expressions. To some extent this structural behaviour was unexpected and has therefore demonstrated that there may be less confidence in the seismic performance of conventionally designed reinforced concrete (RC) structures than previously anticipated. This paper provides an observation-based comparison between the behaviour of RC structural components in laboratory testing and the unexpected structural behaviour of some case study buildings in Christchurch that formed concentrated inelastic deformations. The unexpected behaviour and poor overall seismic performance of ‘real’ buildings (compared to the behaviour of laboratory test specimens) was due to the localization of peak inelastic strains, which in some cases has arguably led to: (i) significantly less ductility capacity; (ii) less hysteretic energy dissipation; and (iii) the fracture of the longitudinal reinforcement. These observations have raised concerns about whether lightly reinforced wall structures can satisfy the performance objective of “Life Safety” at the Ultimate Limit State. The significance of these issues and potential consequences has prompted a review of potential problems with the testing conditions and procedures that are commonly used in seismic experimentations on RC structures. This paper attempts to revisit the principles of RC mechanics, in particular, the influence of loading history, concrete tensile strength, and the quantity of longitudinal reinforcement on the performance of real RC structures. Consideration of these issues in future research on the seismic performance of RC might improve the current confidence levels in newly designed conventional RC structures.
The 2010–2011 Canterbury earthquakes, which involved widespread damage during the February 2011 event and ongoing aftershocks near the Christchurch Central Business District, left this community with more than $NZD 40 billion in losses (~20 % GDP), demolition of approximately 60 % of multi-storey concrete buildings (3 storeys and up), and closure of the core business district for over 2 years. The aftermath of the earthquake sequence has revealed unique issues and complexities for the owners of commercial and multi-storey residential buildings in relation to unexpected technical, legal, and financial challenges when making decisions regarding the future of their buildings impacted by the earthquakes. The paper presents a framework to understand the factors influencing post-earthquake decisions (repair or demolish) on multi-storey concrete buildings in Christchurch. The study, conducted in 2014, includes in-depth investigations on 15 case-study buildings using 27 semi-structured interviews with various property owners, property managers, insurers, engineers, and government authorities in New Zealand. The interviews revealed insights regarding the multitude of factors influencing post-earthquake decisions and losses. As expected, the level of damage and repairability (cost to repair) generally dictated the course of action. There is strong evidence, however, that other variables have significantly influenced the decision on a number of buildings, such as insurance, business strategies, perception of risks, building regulations (and compliance costs), and government decisions. The decision-making process for each building is complex and unique, not solely driven by structural damage. Furthermore, the findings have put the spotlight on insurance policy wordings and the paradoxical effect of insurance on the recovery of Christchurch, leading to other challenges and issues going forward.
This is an interim report from the research study performed within the NHRP Research Project “Impacts of soil liquefaction on land, buildings and buried pipe networks: geotechnical evaluation and design, Project 3: Seismic assessment and design of pipe networks in liquefiable soils”. The work presented herein is a continuation of the comprehensive study on the impacts of Christchurch earthquakes on the buried pipe networks presented in Cubrinovski et al. (2011). This report summarises the performance of Christchurch City’s potable water, waste water and road networks through the 2010-2011 Canterbury Earthquake Sequence (CES), and particularly focuses on the potable water network. It combines evidence based on comprehensive and well-documented data on the damage to the water network, detailed observations and interpretation of liquefaction-induced land damage, records and interpretations of ground motion characteristics induced by the Canterbury earthquakes, for a network analysis and pipeline performance evaluation using a GIS platform. The study addresses a range of issues relevant in the assessment of buried networks in areas affected by strong earthquakes and soil liquefaction. It discusses performance of different pipe materials (modern flexible pipelines and older brittle pipelines) including effects of pipe diameters, fittings and pipeline components/details, trench backfill characteristics, and severity of liquefaction. Detailed breakdown of key factors contributing to the damage to buried pipes is given with reference to the above and other relevant parameters. Particular attention is given to the interpretation, analysis and modelling of liquefaction effects on the damage and performance of the buried pipe networks. Clear link between liquefaction severity and damage rate for the pipeline has been observed with an increasing damage rate seen with increasing liquefaction severity. The approach taken here was to correlate the pipeline damage to LRI (Liquefaction Resistance Index, newly developed parameter in Cubrinovski et al., 2011) which represents a direct measure for the soil resistance to liquefaction while accounting for the seismic demand through PGA. Key quality of the adopted approach is that it provides a general methodology that in conjunction with conventional methods for liquefaction evaluation can be applied elsewhere in New Zealand and internationally. Preliminary correlations between pipeline damage (breaks km-1), liquefaction resistance (LRI) and seismic demand (PGA) have been developed for AC pipes, as an example. Such correlations can be directly used in the design and assessment of pipes in seismic areas both in liquefiable and non-liquefiable areas. Preliminary findings on the key factors for the damage to the potable water pipe network and established empirical correlations are presented including an overview of the damage to the waste water and road networks but with substantially less detail. A comprehensive summary of the damage data on the buried pipelines is given in a series of appendices.
This thesis explores the lived experiences of a group of young Bhutanese former refugees between the ages of 18 to 24 years who were resettled in Christchurch between 2008 and 2010 – prior to the first major earthquake. The main goal of the thesis was to gain an understanding of their ways of coping and a second goal was to explore whether their participation in up to five mindfulness infused counselling sessions had influenced their ways of coping. A qualitative research methodology was used to guide the thesis. Participants were interviewed about the major events in their life and how they coped with them. They were then invited to participate in five sessions of mindfulness infused counselling. Approximately five weeks after their final session had ended they were invited to one final interview to explore the influence of the sessions on their ways of coping. Interviews were recorded and transcribed and research notes were taken of the mindfulness infused counselling sessions. Max van Manen’s method of phenomenology was adopted to interpret the narratives of the youth. Three main themes emerged from the data analysis and these are described as essences of lived coping experiences. The first captures their strong sense of community back in the refugee camp. The second presents the sense of resilience that exists among the Bhutanese former refugees. The third essence indicated the inner strengths of the participants which they said helped them deal with the challenging circumstances that life cast in their direction. This meant that their first experience of an earthquake was not considered the biggest event in their lives. After attending the mindfulness infused counselling sessions’ participants reported positive benefits from giving non-judgemental attention to their thoughts and feelings and they found themselves dealing with their issues proactively. For some participants their ‘accepting’ attitude facilitated better control over their emotions while others reported being able to form deeper connections with nature and other people as a result of being mindful. Other participants reported being able to make peace with the events in their past and even found that they were able to forgive those who tormented their community. However, in the absence of any major event in any of the participants’ lives in the time period following their final counselling session, the research was not able to definitely conclude that using mindful-based counselling facilitates better coping in the face extremely stressful events. There is currently very little research that focuses on the experiences of former refugee youth within New Zealand and how they utilize their capacities to deal with adversities. When this thesis commenced, the Bhutanese were the newest refugee community to be accepted for resettlement in New Zealand. This research partly addresses the limited voice of this community.
The Screw Driving Sounding (SDS) method developed in Japan is a relatively new insitu testing technique to characterise soft shallow sites, typically those required for residential house construction. An SDS machine drills a rod into the ground in several loading steps while the rod is continuously rotated. Several parameters, such as torque, load and speed of penetration, are recorded at every rotation of the rod. The SDS method has been introduced in New Zealand, and the results of its application for characterising local sites are discussed in this study. A total of 164 SDS tests were conducted in Christchurch, Wellington and Auckland to validate/adjust the methodologies originally developed based on the Japanese practice. Most of the tests were conducted at sites where cone penetration tests (CPT), standard penetration tests (SPT) and borehole logs were available; the comparison of SDS results with existing information showed that the SDS method has great potential as an in-situ testing method for classifying the soils. By compiling the SDS data from 3 different cities and comparing them with the borehole logs, a soil classification chart was generated for identifying the soil type based on SDS parameters. Also, a correlation between fines content and SDS parameters was developed and a procedure for estimating angle of internal friction of sand using SDS parameters was investigated. Furthermore, a correlation was made between the tip resistance of the CPT and the SDS data for different percentages of fines content. The relationship between the SPT N value and a SDS parameter was also proposed. This thesis also presents a methodology for identifying the liquefiable layers of soil using SDS data. SDS tests were performed in both liquefied and non-liquefied areas in Christchurch to find a representative parameter and relationship for predicting the liquefaction potential of soil. Plots were drawn of the cyclic shear stress ratios (CSR) induced by the earthquakes and the corresponding energy of penetration during SDS tests. By identifying liquefied or unliquefied layers using three different popular CPT-based methods, boundary lines corresponding to the various probabilities of liquefaction happening were developed for different ranges of fines contents using logistic regression analysis, these could then be used for estimating the liquefaction potential of soil directly from the SDS data. Finally, the drilling process involved in screw driving sounding was simulated using Abaqus software. Analysis results proved that the model successfully captured the drilling process of the SDS machine in sand. In addition, a chart to predict peak friction angles of sandy sites based on measured SDS parameters for various vertical effective stresses was formulated. As a simple, fast and economical test, the SDS method can be a reliable alternative insitu test for soil and site characterisation, especially for residential house construction.
Background: We are in a period of history where natural disasters are increasing in both frequency and severity. They are having widespread impacts on communities, especially on vulnerable communities, those most affected who have the least ability to prepare or respond to a disaster. The ability to assemble and effectively manage Interagency Emergency Response Teams (IERTs) is critical to navigating the complexity and chaos found immediately following disasters. These teams play a crucial role in the multi-sectoral, multi-agency, multi-disciplinary, and inter-organisational response and are vital to ensuring the safety and well-being of vulnerable populations such as the young, aged, and socially and medically disadvantaged in disasters. Communication is key to the smooth operation of these teams. Most studies of the communication in IERTs during a disaster have been focussed at a macro-level of examining larger scale patterns and trends within organisations. Rarely found are micro-level analyses of interpersonal communication at the critical interfaces between collaborating agencies. This study set out to understand the experiences of those working at the interagency interfaces in an IERT set up by the Canterbury District Health Board to respond to the needs of the vulnerable people in the aftermath of the destructive earthquakes that hit Canterbury, New Zealand, in 2010-11. The aim of the study was to gain insights about the complexities of interpersonal communication (micro-level) involved in interagency response coordination and to generate an improved understanding into what stabilises the interagency communication interfaces between those agencies responding to a major disaster. Methods: A qualitative case study research design was employed to investigate how interagency communication interfaces were stabilised at the micro-level (“the case”) in the aftermath of the destructive earthquakes that hit Canterbury in 2010-11 (“the context”). Participant recruitment was undertaken by mapping which agencies were involved within the IERT and approaching representatives from each of these agencies. Data was collected via individual interviews using a semi-structured interview guide and was based on the “Critical Incident Technique”. Subsequently, data was transcribed verbatim and subjected to inductive analysis. This was underpinned theoretically by Weick’s “Interpretive Approach” and supported by Nvivo qualitative data analysis software. Results: 19 participants were interviewed in this study. Out of the inductive analysis emerged two primary themes, each with several sub-factors. The first major theme was destabilising/disruptive factors of interagency communication with five sub-factors, a) conflicting role mandates, b) rigid command structures, c) disruption of established communication structures, d) lack of shared language and understanding, and e) situational awareness disruption. The second major theme stabilising/steadying factors in interagency communication had four sub-factors, a) the establishment of the IERT, b) emergent novel communication strategies, c) establishment of a liaison role and d) pre-existing networks and relationships. Finally, there was a third sub-level identified during inductive analysis, where sub-factors from both primary themes were noted to be uniquely interconnected by emergent “consequences” arising out of the disaster context. Finally, findings were synthesised into a conceptual “Model of Interagency Communication at the Micro-level” based on this case study of the Canterbury earthquake disaster response. Discussion: The three key dimensions of The People, The Connections and The Improvisations served as a framework for the discussion of what stabilises interagency communication interfaces in a major disaster. The People were key to stabilising the interagency interfaces through functioning as a flexible conduit, guiding and navigating communication at the interagency interfaces and improving situational awareness. The Connections provided the collective competence, shared decision-making and prior established relationships that stabilised the micro-level communication at interagency interfaces. And finally, The Improvisations i.e., novel ideas and inventiveness that emerge out of rapidly changing post-disaster environments, also contributed to stabilisation of micro-level communication flows across interagency interfaces in the disaster response. “Command and control” hierarchical structures do provide clear processes and structures for teams working in disasters to follow. However, improvisations and novel solutions are also needed and often emerge from first responders (who are best placed to assess the evolving needs in a disaster where there is a high degree of uncertainty). Conclusion: This study highlights the value of incorporating an interface perspective into any study that seeks to understand the processes of IERTs during disaster responses. It also strengthens the requirement for disaster management frameworks to formally plan for and to allow for the adaptive responsiveness of local teams on the ground, and legitimise and recognise the improvisations of those in the role of emergent boundary spanners in a disaster response. This needs to be in addition to existing formal disaster response mechanisms. This study provides a new conceptual model that can be used to guide future case studies exploring stability at the interfaces of other IERTs and highlights the centrality of communication in the experiences of members of teams in the aftermath of a disaster. Utilising these new perspectives on stabilising communication at the interagency interfaces in disaster responses will have practical implications in the future to better serve the needs of vulnerable people who are at greatest risk of adverse outcomes in a disaster.
In September 2010 and February 2011, the Canterbury region experienced devastating earthquakes with an estimated economic cost of over NZ$40 billion (Parker and Steenkamp, 2012; Timar et al., 2014; Potter et al., 2015). The insurance market played an important role in rebuilding the Canterbury region after the earthquakes. Homeowners, insurance and reinsurance markets and New Zealand government agencies faced a difficult task to manage the rebuild process. From an empirical and theoretic research viewpoint, the Christchurch disaster calls for an assessment of how the insurance market deals with such disasters in the future. Previous studies have investigated market responses to losses in global catastrophes by focusing on the insurance supply-side. This study investigates both demand-side and supply-side insurance market responses to the Christchurch earthquakes. Despite the fact that New Zealand is prone to seismic activities, there are scant previous studies in the area of earthquake insurance. This study does offer a unique opportunity to examine and document the New Zealand insurance market response to catastrophe risk, providing results critical for understanding market responses after major loss events in general. A review of previous studies shows higher premiums suppress demand, but how higher premiums and a higher probability of risk affect demand is still largely unknown. According to previous studies, the supply of disaster coverage is curtailed unless the market is subsidised, however, there is still unsettled discussion on why demand decreases with time from the previous disaster even when the supply of coverage is subsidised by the government. Natural disaster risks pose a set of challenges for insurance market players because of substantial ambiguity associated with the probability of such events occurring and high spatial correlation of catastrophe losses. Private insurance market inefficiencies due to high premiums and spatially concentrated risks calls for government intervention in the provision of natural disaster insurance to avert situations of noninsurance and underinsurance. Political economy considerations make it more likely for government support to be called for if many people are uninsured than if few people are uninsured. However, emergency assistance for property owners after catastrophe events can encourage most property owners to not buy insurance against natural disaster and develop adverse selection behaviour, generating larger future risks for homeowners and governments. On the demand-side, this study has developed an intertemporal model to examine how demand for insurance changes post-catastrophe, and how to model it theoretically. In this intertemporal model, insurance can be sought in two sequential periods of time, and at the second period, it is known whether or not a loss event happened in period one. The results show that period one demand for insurance increases relative to the standard single period model when the second period is taken into consideration, period two insurance demand is higher post-loss, higher than both the period one demand and the period two demand without a period one loss. To investigate policyholders experience from the demand-side perspective, a total of 1600 survey questionnaires were administered, and responses from 254 participants received representing a 16 percent response rate. Survey data was gathered from four institutions in Canterbury and is probably not representative of the entire population. The results of the survey show that the change from full replacement value policy to nominated replacement value policy is a key determinant of the direction of change in the level of insurance coverage after the earthquakes. The earthquakes also highlighted the plight of those who were underinsured, prompting policyholders to update their insurance coverage to reflect the estimated cost of re-building their property. The survey has added further evidence to the existing literature, such as those who have had a recent experience with disaster loss report increased risk perception if a similar event happens in future with females reporting a higher risk perception than males. Of the demographic variables, only gender has a relationship with changes in household cover. On the supply-side, this study has built a risk-based pricing model suitable to generate a competitive premium rate for natural disaster insurance cover. Using illustrative data from the Christchurch Red-zone suburbs, the model generates competitive premium rates for catastrophe risk. When the proposed model incorporates the new RMS high-definition New Zealand Earthquake Model, for example, insurers can find the model useful to identify losses at a granular level so as to calculate the competitive premium. This study observes that the key to the success of the New Zealand dual insurance system despite the high prevalence of catastrophe losses are; firstly the EQC’s flat-rate pricing structure keeps private insurance premiums affordable and very high nationwide homeowner take-up rates of natural disaster insurance. Secondly, private insurers and the EQC have an elaborate reinsurance arrangement in place. By efficiently transferring risk to the reinsurer, the cost of writing primary insurance is considerably reduced ultimately expanding primary insurance capacity and supply of insurance coverage.
The 2010–2011 Canterbury earthquake sequence began with the 4 September 2010, Mw7.1 Darfield earthquake and includes up to ten events that induced liquefaction. Most notably, widespread liquefaction was induced by the Darfield and Mw6.2 Christchurch earthquakes. The combination of well-documented liquefaction response during multiple events, densely recorded ground motions for the events, and detailed subsurface characterization provides an unprecedented opportunity to add well-documented case histories to the liquefaction database. This paper presents and applies 50 high-quality cone penetration test (CPT) liquefaction case histories to evaluate three commonly used, deterministic, CPT-based simplified liquefaction evaluation procedures. While all the procedures predicted the majority of the cases correctly, the procedure proposed by Idriss and Boulanger (2008) results in the lowest error index for the case histories analyzed, thus indicating better predictions of the observed liquefaction response.
Recent field investigations were carried out to define the shear wave velocity (VS) profile and site periods across the Canterbury region, supplementing earlier efforts in urban Christchurch. Active source surface wave testing, ambient wave field (passive) and H/V spectral ratio methods were used to characterise the soil profile in the region. H/V spectral ratio peaks indicate site periods in the range of 5-7 seconds across much of the Canterbury Plains, broadly consistent with those based on a 1D velocity model for the region. Site periods decrease rapidly in the vicinity of the Canterbury foothills and the Banks Peninsula outcrops. In Christchurch, the Riccarton Gravels result in a significant mode of vibration that has a much shorter period than the site period of the entire soil column down to basement rock.
The purpose of this study is to analyse the felt earthquake impacts, resilience and recovery of organizations in Canterbury by comparing three business sectors (accommodation/food services, Education/Training and Manufacturing). A survey of the three sectors in 2013 of Canterbury organizations impacted by the earthquakes revealed significant differences between the three sectors on felt earthquake impacts and resilience. On recovery and mitigation factors, the accommodation/food services sector is not significantly different from the other two sectors. Overall, the survey results presented here indicate that the Accommodation/Food Services sector was the least impacted by the earthquakes in comparison to the Education/Training and Manufacturing sectors. Implications for post-disaster management and recovery of the accommodation sector are suggested.
Following the magnitude 6.3 aftershock in Christchurch, New Zealand, on 22 February 2011, a number of researchers were sent to Christchurch as part of the New Zealand Natural Hazard Research Platform funded “Project Masonry” Recovery Project. Their goal was to document and interpret the damage to the masonry buildings and churches in the region. Approximately 650 unreinforced and retrofitted clay brick masonry buildings in the Christchurch area were surveyed for commonly occurring failure patterns and collapse mechanisms. The entire building stock of Christchurch, and in particular the unreinforced masonry building stock, is similar to that in the rest of New Zealand, Australia, and abroad, so the observations made here are relevant for the entire world.
"The nuclear meltdown at Fukushima ... the Fonterra botulism scare ... the Christchurch earthquakes – in all these recent crises the role played by scientists has been under the spotlight. What is the first duty of scientists in a crisis – to the government, to their employer, or to the wider public desperate for information? And what if these different objectives clash? In this penetrating BWB Text, leading scientist Shaun Hendy finds that in New Zealand, the public obligation of the scientist is often far from clear and that there have been many disturbing instances of scientists being silenced. Experts who have information the public seeks, he finds, have been prevented from speaking out. His own experiences have led him to conclude that New Zealanders have few scientific institutions that feel secure enough to criticise the government of the day." - Publisher information. http://librarysearch.auckland.ac.nz/UOA2_A:Combined_Local:uoa_alma21259423940002091
The Mw 7.1 Darfield earthquake generated a ~30 km long surface rupture on the Greendale Fault and significant surface deformation related to related blind faults on a previously unrecognized fault system beneath the Canterbury Plains. This earthquake provided the opportunity for research into the patterns and mechanisms of co-seismic and post-seismic crustal deformation. In this thesis I use multiple across-fault EDM surveys, logic trees, surface investigations and deformation feature mapping, seismic reflection surveying, and survey mark (cadastral) re-occupation using GPS to quantify surface displacements at a variety of temporal and spatial scales. My field mapping investigations identified shaking and crustal displacement-induced surface deformation features south and southwest of Christchurch and in the vicinity of the projected surface traces of the Hororata Blind and Charing Cross Faults. The data are consistent with the high peak ground accelerations and broad surface warping due to underlying reverse faulting on the Hororata Blind Fault and Charing Cross Fault. I measured varying amounts of post-seismic displacement at four of five locations that crossed the Greendale Fault. None of the data showed evidence for localized dextral creep on the Greendale Fault surface trace, consistent with other studies showing only minimal regional post-seismic deformation. Instead, the post-seismic deformation field suggests an apparent westward translation of northern parts of the across-fault surveys relative to the southern parts of the surveys that I attribute to post-mainshock creep on blind thrusts and/or other unidentified structures. The seismic surveys identified a deformation zone in the gravels that we attribute to the Hororata Blind Fault but the Charing Cross fault was not able to be identified on the survey. Cadastral re-surveys indicate a deformation field consistent with previously published geodetic data. We use this deformation with regional strain rates to estimate earthquake recurrence intervals of ~7000 to > 14,000 yrs on the Hororata Blind and Charing Cross Faults.
This thesis examines the closing of Aranui High School in 2016, a low socio-economic secondary school in eastern Christchurch, New Zealand, and reflects on its history through the major themes of innovation and the impact of central government intervention. The history is explored through the leadership of the school principals, and the necessity for constant adaptation by staff to new ways of teaching and learning, driven by the need to accommodate a more varied student population – academically, behaviourally and culturally – than most other schools in wider Christchurch. Several extreme changes, following a neoliberal approach to education policies at a national government level, impacted severely on the school’s ability to thrive and even survive over the 57 years of its existence, with the final impact of the 2010 and 2011 Canterbury earthquakes leading indirectly to Aranui High’s closure. The earthquakes provided the National government with the impetus to advocate for change to education in Christchurch; changes which impacted negatively on many schools in Christchurch, including Aranui High School. The announcement of the closure of Aranui High shocked many staff and students, who were devastated that the school would no longer exist. Aranui High School, Aranui Primary School, Wainoni Primary School and Avondale Primary School were all closed to make way for Haeata Community Campus, a year 1 to 13 school, which was built on the Aranui High site. Aranui High School served the communities of eastern Christchurch for 57 years from 1960 and deserves acknowledgment and remembrance, and my hope is that this thesis will provide a fair representation of the school’s story, including its successes and challenges, while also explaining the reasons behind the eventual closure. This thesis contributes to New Zealand public history and uses mixed research methods to examine Aranui High School’s role as a secondary school in eastern Christchurch. I argue that the closure of Aranui High School in 2016 was an unjustified act by the Ministry of Education.
A number of reverse and strike-slip faults are distributed throughout mid-Canterbury, South Island, New Zealand, due to oblique continental collision. There is limited knowledge on fault interaction in the region, despite historical multi-fault earthquakes involving both reverse and strike-slip faults. The surface expression and paleoseismicity of these faults can provide insights into fault interaction and seismic hazards in the region. In this thesis, I studied the Lake Heron and Torlesse faults to better understand the key differences between these two adjacent faults located within different ‘tectonic domains’. Recent activity and surface expression of the Lake Heron fault was mapped and analysed using drone survey, Structure-from-Motion (SfM) derived Digital Surface Model (DSM), aerial image, 5 m-Digital Elevation Model (DEM), luminescence dating technique, and fold modelling. The results show a direct relationship between deformation zone width and the thickness of the gravel deposits in the area. Fold modelling using fault dip, net slip and gravel thickness produces a deformation zone comparable to the field, indicating that the fault geometry is sound and corroborating the results. This result Is consistent with global studies that demonstrate deposit (or soil thickness) correlates to fault deformation zone width, and therefore is important to consider for fault displacement hazard. A geomorphological study on the Torlesse fault was conducted using SfM-DSM, DEM and aerial images Ground Penetrating Radar (GPR) survey, trenching, and radiocarbon and luminescence dating. The results indicate that the Torlesse fault is primarily strike-slip with some dip slip component. In many places, the bedding-parallel Torlesse fault offsets post-glacial deposits, with some evidence of flexural slip faulting due to folding. Absolute dating of offset terraces using radiocarbon dating and slip on fault determined from lateral displacement calculating tool demonstrates the fault has a slip rate of around 0.5 mm/year to 1.0 mm/year. The likelihood of multi-fault rupture in the Torlesse Range has been characterised using paleoseismic trenching, a new structural model, and evaluation of existing paleoseismic data on the Porters Pass fault. Identification of overlapping of paleoseismic events in main Torlesse fault, flexural-slip faults and the Porters Pass fault in the Torlesse Range shows the possibility of distinct or multi-fault rupture on the Torlesse fault. The structural connectivity of the faults in the Torlesse zone forming a ‘flower structure’ supports the potential of multi-fault rupture. Multi-fault rupture modelling carried out in the area shows a high probability of rupture in the Porters Pass fault and Esk fault which also supports the co-rupture probability of faults in the region. This study offers a new understanding of the chronology, slip distribution, rupture characteristics and possible structural and kinematic relationship of Lake Heron fault and Torlesse fault in the South Island, New Zealand.
As cities evolve, change and grow, the need and desire for adaptable architecture becomes evident across the nation. Architecture needs to undertake techniques that are flexible in order to adapt and align with the development of future generations in New Zealand. The Education industry is a primary example of a sector which requires flexibility within both classroom architectural form and interior configuration. This is a resultant of the recently updated Ministry of Education requirements; which state that every new classroom built or renovated nationwide, must implement the MoE classroom design standards for Innovative Learning Environments. ILE teaching spaces are configured as an open plan interior, supporting flexibility in classroom arrangement and teaching techniques. ILE classrooms are capable of evolving and adapting as educational practices evolve and change, allowing schools to remain modern and future focused. As part of this movement to ILE, the Ministry of Education has also recently made an attempt to improve the quality of temporary classrooms. This has been done by looking into the initiation of a programme that utilizes relocatable classroom buildings. Relocatable classrooms have been selected for multiple reasons, primarily flexibility. Flexibility is key for a school environment as it allows the school to actively respond to fluctuating school rolls. It is anticipated that the programme will provide a faster delivery process with a standardised design that allows the classrooms to be relocated from one school to another with relative ease. Following the devastating February 2011 earthquake the Greater Christchurch Region, the Education sector is in the midst of the Canterbury Schools Rebuild Programme. As a repercussion of this natural disaster, the majority of Christchurch schools have redevelopment or rebuild projects in progress, with preliminary design phases already in action for a small group of select schools regarded as high priority. The primary funding for these projects are sourced from insurance money, implementing tight budget restrictions, affecting the architectural design, quality and speed of the construction and repair works. The available funding limits the affordable classroom options to basic teaching spaces that have been stripped back to simple architectural forms, dictating not only the re-design, but also how our future generations will learn. Thus causing the development of the new student-led learning ILE concept to become controlled by existing construction techniques and the Rebuild Programmes budget restrictions. This thesis focuses on the future proofing of New Zealand schools by providing an affordable and time efficient alternative option to the current static, traditional construction, an option that has the ability to cater to the unpredictable fluctuating school rolls across the nation. This has been done by developing a prefabricated system for standalone classroom blocks. These blocks have the ability to be relocated between different school sites, dynamically catering to the unpredictable school roll numbers experienced across New Zealand. This site flexibility is reflected with the interior flexibility in the classrooms, enhancing the internal teaching space composition and challenges the existing design standards set by the Ministry of Education for Innovative Learning Environments. This system is called “Flexi-Ed”. Flexibility has been a key driver for this thesis, as the prefabricated structure is have to be flexible in three ways; first in the sense of being easy to assemble and disassemble. Second by offering flexible interior learning environments and thirdly the joints of the structure are designed with the ability to be flexible in order to cope with seismic activity. These three principles will provide schools with long term flexibility, minimal on-site interruption and heighten the standard of ILE across the nation. I strive to provide schools with long term flexibility and minimal site interruption, whilst heightening the standard of Innovative Learning Environments across New Zealand.
On 4 September 2010, a magnitude Mw 7.1 earthquake struck the Canterbury region on the South Island of New Zealand. The epicentre of the earthquake was located in the Darfield area about 40 km west of the city of Christchurch. Extensive damage was inflicted to lifelines and residential houses due to widespread liquefaction and lateral spreading in areas close to major streams, rivers and wetlands throughout Christchurch and Kaiapoi. Unreinforced masonry buildings also suffered extensive damage throughout the region. Despite the severe damage to infrastructure and residential houses, fortunately, no deaths occurred and only two injuries were reported in this earthquake. From an engineering viewpoint, one may argue that the most significant aspects of the 2010 Darfield Earthquake were geotechnical in nature, with liquefaction and lateral spreading being the principal culprits for the inflicted damage. Following the earthquake, an intensive geotechnical reconnaissance was conducted to capture evidence and perishable data from this event. This paper summarizes the observations and preliminary findings from this early reconnaissance work.
A multi-disciplinary geo-structural-environmental engineering project funded by the Ministry of Business Innovation and Employment (MBIE) is being carried out at the University of Canterbury. The project aims at developing an eco-friendly seismic isolation foundation system which will improve the seismic performance of medium-density low-rise buildings. Such system is characterized by two main elements: 1) granulated scrap rubber mixed with gravelly soils to be placed beneath the structure, with the goal damping part of the seismic energy before it reaches the superstructure; and 2) a basement raft made of steel-fibre reinforced rubberised concrete (SFRRuC) to enhance the flexibility and toughness of the foundation, looking at better accommodating the displacement demand. In this paper, the main objectives, scope and methodology of the project will be briefly described. A literature review of the engineering properties of steel-fibre reinforced rubberised concrete (RuC) will be presented. Then, preliminary results on concrete mixes with different rubber and steel fibres content will be exhibited.
The Canterbury earthquakes, which involved widespread damage in the February 2011 event and ongoing aftershocks near the Christchurch central business district (CBD), presented decision-makers with many recovery challenges. This paper identifies major government decisions, challenges, and lessons in the early recovery of Christchurch based on 23 key-informant interviews conducted 15 months after the February 2011 earthquake. It then focuses on one of the most important decisions – maintaining the cordon around the heavily damaged CBD – and investigates its impacts. The cordon displaced 50,000 central city jobs, raised questions about (and provided new opportunities for) the long-term viability of downtown, influenced the number and practice of building demolitions, and affected debris management; despite being associated with substantial losses, the cordon was commonly viewed as necessary, and provided some benefits in facilitating recovery. Management of the cordon poses important lessons for planning for catastrophic urban earthquakes around the world.
A major lesson from the 2011 Christchurch earthquake was the apparent lack of ductility of some lightly reinforced concrete (RC) wall structures. In particular, the structural behaviour of the critical wall in the Gallery Apartments building demonstrated that the inelastic deformation capacity of a structure, as well as potentially brittle failure of the reinforcement, is dependent on the level of bond deterioration between reinforcement and surrounding concrete that occurs under seismic loading. This paper presents the findings of an experimental study on bond behaviour between deformed reinforcing bars and the surrounding concrete. Bond strength and relative bond slip was evaluated using 75 pull-out tests under monotonic and cyclic loading. Variations of the experiments include the loading rate, loading history, concrete strength (25 to 70 MPa), concrete age, cover thickness, bar diameter (16 and 20 mm), embedded length, and the position of the embedded bond region within the specimen (deep within or close to free surface). Select test results are presented with inferred implications for RC structures.
The last seven years have seen southern New Zealand a ected by several large and damaging earthquakes: the moment magnitude (MW) 7.8 Dusky Sound earthquake on 15 July 2009, the MW 7.1 Dar eld (Canterbury) earthquake on 4 September 2010, and most notably the MW 6.2 Christchurch earthquake on 22 February 2011 and the protracted aftershock sequence. In this thesis, we address the postseismic displacement produced by these earthquakes using methods of satellite-based geodetic measurement, known as Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS), and computational modelling. We observe several ground displacement features in the Canterbury and Fiordland regions during three periods: 1) Following the Dusky Sound earthquake; 2) Following the Dar eld earthquake and prior to the Christchurch earthquake; and 3) Following the Christchurch earthquake until February 2015. The ground displacement associated with postseismic motion following the Dusky Sound earthquake has been measured by continuous and campaign GPS data acquired in August 2009, in conjunction with Di erential Interferometric Synthetic Aperture Radar (DInSAR) observations. We use an afterslip model, estimated by temporal inversion of geodetic data, with combined viscoelastic rebound model to account for the observed spatio-temporal patterns of displacement. The two postseismic processes together induce a signi cant displacement corresponding to principal extensional and contractual strain rates of the order of 10⁻⁷ and 10⁻⁸ yr⁻¹ respectively, across most of the southern South Island. We also analyse observed postseismic displacement following the Dusky Sound earthquake using a new inversion approach in order to describe afterslip in an elasticviscoelastic medium. We develop a mathematical framework, namely the "Iterative Decoupling of Afterslip and Viscoelastic rebound (IDAV)" method, with which to invert temporally dense and spatially sparse geodetic observations. We examine the IDAV method using both numerical and analytical simulations of Green's functions. For the post-Dar eld time interval, postseismic signals are measured within approximately one month of the mainshock. The dataset used for the post-Dar eld displacement spans the region surrounding previously unrecognised faults that ruptured during the mainshock. Poroelastic rebound in a multi-layered half-space and dilatancy recovery at shallow depths provide a satisfactory t with the observations. For the post-Christchurch interval, campaign GPS data acquired in February 2012 to February 2015 in four successive epochs and 66 TerraSAR-X (TSX) SAR acquisitions in descending orbits between March 2011 and May 2014 reveal approximately three years of postseismic displacement. We detect movement away from the satellite of ~ 3 mm/yr in Christchurch and a gradient of displacement of ~ 4 mm/yr across a lineament extending from the westernmost end of the Western Christchurch Fault towards the eastern end of the Greendale East Fault. The postseismic signals following the Christchurch earthquake are mainly accounted for by afterslip models on the subsurface lineament and nearby faults.
This study contains an evaluation of the seismic hazard associated with the Springbank Fault, a blind structure discovered in 1998 close to Christchurch. The assessment of the seismic hazard is approached as a deterministic process in which it is necessary to establish: 1) fault characteristics; 2) the maximum earthquake that the fault is capable of producing and 3) ground motions estimations. Due to the blind nature of the fault, conventional techniques used to establish the basic fault characteristics for seismic hazard assessments could not be applied. Alternative methods are used including global positioning system (GPS) surveys, morphometric analyses along rivers, shallow seismic reflection surveys and computer modelling. These were supplemented by using multiple empirical equations relating fault attributes to earthquake magnitude, and attenuation relationships to estimate ground motions in the near-fault zone. The analyses indicated that the Springbank Fault is a reverse structure located approximately 30 km to the northwest of Christchurch, along a strike length of approximately 16 km between the Eyre and Ashley River. The fault does not reach the surface, buy it is associated with a broad anticline whose maximum topographic expression offers close to the mid-length of the fault. Two other reverse faults, the Eyrewell and Sefton Faults, are inferred in the study area. These faults, together with the Springbank and Hororata Faults and interpreted as part of a sys of trust/reverse faults propagating from a decollement located at mid-crustal depths of approximately 14 km beneath the Canterbury Plains Within this fault system, the Springbank Fault is considered to behave in a seismically independent way, with a fault slip rate of ~0.2 mm/yr, and the capacity of producing a reverse-slip earthquake of moment magnitude ~6.4, with an earthquake recurrence of 3,000 years. An earthquake of the above characteristics represents a significant seismic hazard for various urban centres in the near-fault zone including Christchurch, Rangiora, Oxford, Amberley, Kaiapoi, Darfield, Rollestion and Cust. Estimated peak ground accelerations for these towns range between 0.14 g to 0.5 g.
Six months after the 4 September 2010 Mw 7.1 Darfield (Canterbury) earthquake, a Mw 6.2 Christchurch (Lyttelton) aftershock struck Christchurch on the 22 February 2011. This earthquake was centred approximately 10km south-east of the Christchurch CBD at a shallow depth of 5km, resulting in intense seismic shaking within the Christchurch central business district (CBD). Unlike the 4 Sept earthquake when limited-to-moderate damage was observed in engineered reinforced concrete (RC) buildings [35], in the 22 February event a high number of RC Buildings in the Christchurch CBD (16.2 % out of 833) were severely damaged. There were 182 fatalities, 135 of which were the unfortunate consequences of the complete collapse of two mid-rise RC buildings. This paper describes immediate observations of damage to RC buildings in the 22 February 2011 Christchurch earthquake. Some preliminary lessons are highlighted and discussed in light of the observed performance of the RC building stock. Damage statistics and typical damage patterns are presented for various configurations and lateral resisting systems. Data was collated predominantly from first-hand post-earthquake reconnaissance observations by the authors, complemented with detailed assessment of the structural drawings of critical buildings and the observed behaviour. Overall, the 22 February 2011 Mw 6.2 Christchurch earthquake was a particularly severe test for both modern seismically-designed and existing non-ductile RC buildings. The sequence of earthquakes since the 4 Sept 2010, particularly the 22 Feb event has confirmed old lessons and brought to life new critical ones, highlighting some urgent action required to remedy structural deficiencies in both existing and “modern” buildings. Given the major social and economic impact of the earthquakes to a country with strong seismic engineering tradition, no doubt some aspects of the seismic design will be improved based on the lessons from Christchurch. The bar needs to and can be raised, starting with a strong endorsement of new damage-resisting, whilst cost-efficient, technologies as well as the strict enforcement, including financial incentives, of active policies for the seismic retrofit of existing buildings at a national scale.
The connections between walls of unreinforced masonry (URM) buildings and flexible timber diaphragms are critical building components that must perform adequately before desirable earthquake response of URM buildings may be achieved. Field observations made during the initial reconnaissance and the subsequent damage surveys of clay brick URM buildings following the 2010/2011 Canterbury, New Zealand earthquakes revealed numerous cases where anchor connections joining masonry walls or parapets with roof or floor diaphragms appeared to have failed prematurely. These observations were more frequent for the case of adhesive anchor connections than for the case of through-bolt connections (i.e. anchorages having plates on the exterior façade of the masonry walls). Subsequently, an in-field test program was undertaken in an attempt to evaluate the performance of adhesive anchor connections between unreinforced clay brick URM walls and roof or floor diaphragm. The study consisted of a total of almost 400 anchor tests conducted in eleven existing URM buildings located in Christchurch, Whanganui and Auckland. Specific objectives of the study included the identification of failure modes of adhesive anchors in existing URM walls and the influence of the following variables on anchor load-displacement response: adhesive type, strength of the masonry materials (brick and mortar), anchor embedment depth, anchor rod diameter, overburden level, anchor rod type, quality of installation and the use of metal foil sleeve. In addition, the comparative performance of bent anchors (installed at an angle of minimum 22.5o to the perpendicular projection from the wall surface) and anchors positioned horizontally was investigated. Observations on the performance of wall-to-diaphragm connections in the 2010/2011 Canterbury earthquakes and a snapshot of the performed experimental program and the test results are presented herein. http://hdl.handle.net/2292/21050
