The Canterbury earthquakes that happened in 2010 and 2011 have attracted many migrant workers to the region to assist with the rebuilding effort. However, research on the impact of influx of migrants on the labour market outcomes of a local industry post-disaster is limited internationally and locally. The main objective of this study is to examine the impact of the Canterbury earthquakes on the changes in demographic composition and occupational structure for the local and foreign workers in the Greater Christchurch construction industry. Replicating the discrete dependent variable regression methods used in the study by Sisk and Bankston III (2014), this study also aimed to compare their findings on the impact of the influx of migrants on the New Orleans construction industry with outcomes in Greater Christchurch. Customised data from New Zealand Censuses 2006 and 2013 were used to represent the pre- and post-earthquake periods. This study found that the rebuild has provided opportunities for migrant workers to enter the Greater Christchurch construction industry. The increased presence of migrant construction workers did not displace the locals. In fact, the likelihoods for both locals’ and migrants’ participation in the industry improved post-earthquakes. The earthquakes also increased overall workers’ participation at the lowest end of the occupational structure. However, the earthquakes created few significant changes to the distribution of local and migrant workers at the various occupational levels in the industry. Local workers still dominated all occupational levels post-earthquakes. The aggregated education levels of the construction workers were higher post-earthquakes, particularly among the migrant workers. Overall, migrant workers in the Greater Christchurch construction industry were more diverse, more educated and participated in higher occupational levels than migrants assisting in the New Orleans rebuild, due possibly to differences in immigration policies between New Zealand and the United States of America.
Five years on since the first major earthquake struck the Canterbury region, the reconstruction is well advanced. Christchurch is a city in transition. This report considers trends in resourcing and employment practice of Canterbury construction organisations in response to the projected market changes (2015-2016). The report draws on the interviews with 18 personnel from 16 construction organisations and recovery agencies in October 2015. It provides a summary of perceived changes in the construction market in Canterbury, evidence of what steps construction businesses have been taking, how they have prepared for likely changes in the reconstruction sector, as well as the perceived alignment of public policies with the industry response.
This report provides an understanding of the nature of Canterbury subcontracting businesses operating in the space of earthquake reconstruction in Christchurch. It offers an in-depth look at the factors that influence the development of their capacity and capability to withstand the impact of volatile economic cycles, including the 2008 global financial crisis and the subsequent 2010/11 Canterbury earthquakes. There have been significant changes to the business models of the 13 subcontracting businesses studied since the earthquakes. These changes can be seen in the ways the case study subcontractors have adapted to cope with the changing demands that the rebuild posed. Apart from the magnitude of reconstruction works and new developments that directly affect the capacity of subcontracting businesses in Canterbury, case studies found that subcontractors’ capacity and capability to meet the demand varies and is influenced by the: subcontractors’ own unique characteristics, which are often shaped by changing circumstances in a dynamic and uncertain recovery process; and internal factors in relation to the company’s goal and employees’ needs
Predictive modelling provides an efficient means to analyse the coastal environment and generate knowledge for long term urban planning. In this study, the numerical models SWAN and XBeach were incorporated into the ESRI ArcGIS interface by means of the BeachMMtool. This was applied to the Greater Christchurch coastal environment to simulate geomorphological evolution through hydrodynamic forcing. Simulations were performed using the recent sea level rise predictions by the Intergovernmental Panel on Climate Change (2013) to determine whether the statutory requirements outlined in the New Zealand Coastal Policy Statement 2010 are consistent with central, regional and district designations. Our results indicate that current land use zoning in Greater Christchurch is not consistent with these predictions. This is because coastal hazard risk has not been thoroughly quantified during the process of installing the Canterbury Earthquake Recovery Authority residential red zone. However, the Christchurch City Council’s flood management area does provide an extent to which managed coastal retreat is a real option. The results of this research suggest that progradation will continue to occur along the Christchurch foreshore due to the net sediment flux retaining an onshore direction and the current hydrodynamic activity not being strong enough to move sediment offshore. However, inundation during periods of storm surge poses a risk to human habitation on low lying areas around the Avon-Heathcote Estuary and the Brooklands lagoon.
In the aftermath of the 2010-2011 Canterbury earthquakes in New Zealand, the residual capacity and reparability of damaged reinforced concrete (RC) structures was an issue pertinent to building owners, insurers, and structural engineers. Three precast RC moment-resisting frame specimens were extracted during the demolition of the Clarendon Tower in Christchurch after sustaining earthquake damage. These specimens were subjected to quasi-static cyclic testing as part of a research program to determine the reparability of the building. It was concluded that the precast RC frames were able to be repaired and retrofitted to an enhanced strength capacity with no observed reduction in displacement capacity, although the frames with “shear-ductile” detailing exhibited less displacement ductility capacity and energy dissipation capacity than the more conventionally detailed RC frames. Furthermore, the cyclic test results from the earthquake-damaged RC frames were used to verify the predicted inelastic demands applied to the specimens during the 2010-2011 Canterbury earthquakes. https://www.concrete.org/publications/acistructuraljournal.aspx
The author followed five primary (elementary) schools over three years as they responded to and began to recover from the 2010–2011 earthquakes in and around the city of Christchurch in the Canterbury region of New Zealand. The purpose was to capture the stories for the schools themselves, their communities, and for New Zealand’s historical records. From the wider study, data from the qualitative interviews highlighted themes such as children’s responses or the changing roles of principals and teachers. The theme discussed in this article, however, is the role that schools played in the provision of facilities and services to meet (a) physical needs (food, water, shelter, and safety); and (b) emotional, social, and psychological needs (communication, emotional support, psychological counseling, and social cohesion)—both for themselves and their wider communities. The role schools played is examined across the immediate, short-, medium-, and long-term response periods before being discussed through a social bonding theoretical lens. The article concludes by recommending stronger engagement with schools when considering disaster policy, planning, and preparation http://www.schoolcommunitynetwork.org/SCJ.aspx
Following the 2010/2011 Canterbury earthquakes the seismic design of buildings with precast concrete panels has received significant attention. Although this form of construction generally performed adequately in Christchurch, there were a considerable number of precast concrete panel connection failures. This observation prompted a review of more than 4700 panel details from 108 buildings to establish representative details used in both existing and new multi-storey and low rise industrial precast concrete buildings in three major New Zealand cities of Auckland, Wellington and Christchurch. Details were collected from precast manufacturers and city councils and were categorised according to type. The detailing and quantity of each reviewed connection type in the sampled data is reported, and advantages and potential deficiencies of each connection type are discussed. The results of this survey provide a better understanding of the relative prevalence of common detailing used in precast concrete panels and guidance for the design of future experimental studies. http://www.nzsee.org.nz/publications/nzsee-quarterly-bulletin/
Unreinforced masonry (URM) cavity-wall construction is a form of masonry where two leaves of clay brick masonry are separated by a continuous air cavity and are interconnected using some form of tie system. A brief historical introduction is followed by details of a survey undertaken to determine the prevalence of URM cavity-wall buildings in New Zealand. Following the 2010/2011 Canterbury earthquakes it was observed that URM cavity-walls generally suffered irreparable damage due to a lack of effective wall restraint and deficient cavity-tie connections, combined with weak mortar strength. It was found that the original cavity-ties were typically corroded due to moisture ingress, resulting in decreased lateral loadbearing capacity of the cavity-walls. Using photographic data pertaining to Christchurch URM buildings that were obtained during post-earthquake reconnaissance, 252 cavity-walls were identified and utilised to study typical construction details and seismic performance. The majority (72%, 182) of the observed damage to URM cavity-wall construction was a result of out-of-plane type wall failures. Three types of out-of-plane wall failure were recognised: (1) overturning response, (2) one-way bending, and (3) two-way bending. In-plane damage was less widely observed (28%) and commonly included diagonal shear cracking through mortar bed joints or bricks. The collected data was used to develop an overview of the most commonly-encountered construction details and to identify typical deficiencies in earthquake response that can be addressed via the selection and implementation of appropriate mitigation interventions. http://www.journals.elsevier.com/structures
In 2013 Becca Wood, Spatial Performance Practitioner, and Molly Mullen, Applied Theatre Practitioner, collaborated to create a short ambulatory performance with audio score for a group of drama educators attending a conference workshop on the possibilities of walking as performance. The performance was created remotely from the intended site: Rangi Ruru Girls’ School, in Christchurch, New Zealand. Following the destruction of the 2012 earthquake, this site was in a state of transformation and recovery. The performance walk attended to the histories, geographies and politics of this place, somatically, architecturally and socially. This paper engages with three critical questions: How might mediated listening and walking activate the coming together of bodies and place? What performative shifts occurred for the participants in the walk and workshop? How might we come to our senses? Through a performative practice of mediated site-based listening and walking, this paper is a reflection on the creative process and performance. We consider the potential for technologically mediated performance to offer new modes for learning and creative practice through interdisciplinary and evolving intermedial practices. http://www.tandfonline.com/toc/crde20/current AM - Accepted Manuscript
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 adhesive anchor connections than for through-bolt connections (i.e., anchorages having plates on the exterior facade 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 mesh sleeves. In addition, the comparative performance of bent anchors (installed at an angle of minimum 22.5° 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, a summary of the performed experimental program and test results, and a proposed pull-out capacity relationship for adhesive anchors installed into multi-leaf clay brick masonry are presented herein. AM - Accepted Manuscript
A dramatic consequence of the Christchurch, New Zealand, earthquakes of 2010 and 2011 was the widespread liquefaction in the city. Part of the central business district (CBD) was badly affected by liquefaction but elsewhere large volumes of ejecta were not evident for those parts of the CBD where the upper layers in the soil profile are sandy gravel and gravelly sand. The purpose of the paper is to investigate the effect of the gravel permeability on the rise and dissipation of excess pore water pressure during cyclic loading of a soil profile idealised from Christchurch data. The Cyclic1D software, which performs one-dimensional non-linear effective stress site response analysis, was used. Permeability values associated with gravel were found to suppress the cyclic accumulation of excess pore water pressure in gravel layers. Given that there has not been any systematic measurement of the in situ permeability of the gravels in Christchurch, the modelling in the paper suggests that likely values for the bulk permeability of the gravel layers are within the range suggested in the geotechnical literature. However, the work reported is of wider application than Christchurch and emphasises the controlling influence of permeability on the accumulation and dissipation of cyclic pore pressures. VoR - Version of Record
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/
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Five years after the devastating series of earthquakes in Christchurch, New Zealand, the structural engineering community is now focussing on low damage design by either proactively reducing the possibility of significant damage to primary steel members (i.e. developing seismic resisting systems that will deliver a high damage threshold in severe earthquakes) or by improved detailing of the primary steel members for rapid replacement. This paper presents a development of Eccentrically Braced Frames (EBFs) with replaceable active links. It uses the bolted flange- and web splicing concept to connect the active link to the collector beam or column. Finite element analyses have been performed to investigate the behaviour and reliability of EBFs with this new type replaceable active link. The results show a stable hysteretic behaviour and more significantly easier replacement of the damaged active link in comparison with conventional EBFs.
Many large-scale earthquakes all over the world have highlighted the impact of soil liquefaction to the built environment, but the scale of liquefaction-induced damage experienced in Christchurch and surrounding areas following the 2010-2011 Canterbury earthquake sequence (CES) was unparalleled, especially in terms of impact to an urban area. The short time interval between the large earthquakes presented a very rare occasion to examine liquefaction mechanism in natural deposits. The re-liquefaction experienced by the city highlighted the high liquefaction susceptibility of soil deposits in Christchurch, and presented a very challenging problem not only to the local residents but to the geotechnical engineering profession. This paper summarises the lessons learned from CES, and the impacts of the observations made to the current practice of liquefaction assessment and mitigation.
A number of field testing techniques, such as standard penetration test (SPT), cone penetration test (CPT), and Swedish weight sounding (SWS), are popularly used for in-situ characterisation. The screw driving sounding (SDS) method, which has been recently developed in Japan, is an improved version of the SWS technique and measures more parameters, including the required torque, load, speed of penetration and rod friction; these provide more robust way of characterising soil stratigraphy. It is a cost-efficient technique which uses a machine-driven and portable device, making it ideal for testing in small-scale and confined areas. Moreover, with a testing depth of up to 10-15m, it is suitable for liquefaction assessment. Thus, the SDS method has great potential as an in-situ testing method for geotechnical site characterisation, especially for residential house construction. In this paper, the results of SDS tests performed at a variety of sites in New Zealand are presented. The soil database was employed to develop a soil classification chart based on SDS-derived parameters. Moreover, using the data obtained following the 2010-2011 Christchurch Earthquake Se-quence, a methodology was established for liquefaction potential evaluation using SDS data. http://www.isc5.com.au/wp-content/uploads/2016/09/1345-2-ORENSE.pdf
In September 2010 and February 2011 the Canterbury region of New Zealand was struck by two powerful earthquakes, registering magnitude 7.1 and 6.3 respectively on the Richter scale. The second earthquake was centred 10 kilometres south-east of the centre of Christchurch (the region’s capital and New Zealand’s third most populous urban area, with approximately 360,000 residents) at a depth of five kilometres. 185 people were killed, making it the second deadliest natural disaster in New Zealand’s history. (66 people were killed in the collapse of one building alone, the six-storey Canterbury Television building.) The earthquake occurred during the lunch hour, increasing the number of people killed on footpaths and in buses and cars by falling debris. In addition to the loss of life, the earthquake caused catastrophic damage to both land and buildings in Christchurch, particularly in the central business district. Many commercial and residential buildings collapsed in the tremors; others were damaged through soil liquefaction and surface flooding. Over 1,000 buildings in the central business district were eventually demolished because of safety concerns, and an estimated 70,000 people had to leave the city after the earthquakes because their homes were uninhabitable. The New Zealand Government declared a state of national emergency, which stayed in force for ten weeks. In 2014 the Government estimated that the rebuild process would cost NZ$40 billion (approximately US$27.3 billion, a cost equivalent to 17% of New Zealand’s annual GDP). Economists now estimate it could take the New Zealand economy between 50 and 100 years to recover. The earthquakes generated tens of thousands of insurance claims, both against private home insurance companies and against the New Zealand Earthquake Commission, a government-owned statutory body which provides primary natural disaster insurance to residential property owners in New Zealand. These ranged from claims for hundreds of millions of dollars concerning the local port and university to much smaller claims in respect of the thousands of residential homes damaged. Many of these insurance claims resulted in civil proceedings, caused by disputes about policy cover, the extent of the damage and the cost and/or methodology of repairs, as well as failures in communication and delays caused by the overwhelming number of claims. Disputes were complicated by the fact that the Earthquake Commission provides primary insurance cover up to a monetary cap, with any additional costs to be met by the property owner’s private insurer. Litigation funders and non-lawyer claims advocates who took a percentage of any insurance proceeds also soon became involved. These two factors increased the number of parties involved in any given claim and introduced further obstacles to resolution. Resolving these disputes both efficiently and fairly was (and remains) central to the rebuild process. This created an unprecedented challenge for the justice system in Christchurch (and New Zealand), exacerbated by the fact that the Christchurch High Court building was itself damaged in the earthquakes, with the Court having to relocate to temporary premises. (The High Court hears civil claims exceeding NZ$200,000 in value (approximately US$140,000) or those involving particularly complex issues. Most of the claims fell into this category.) This paper will examine the response of the Christchurch High Court to this extraordinary situation as a case study in innovative judging practices and from a jurisprudential perspective. In 2011, following the earthquakes, the High Court made a commitment that earthquake-related civil claims would be dealt with as swiftly as the Court's resources permitted. In May 2012, it commenced a special “Earthquake List” to manage these cases. The list (which is ongoing) seeks to streamline the trial process, resolve quickly claims with precedent value or involving acute personal hardship or large numbers of people, facilitate settlement and generally work proactively and innovatively with local lawyers, technical experts and other stakeholders. For example, the Court maintains a public list (in spreadsheet format, available online) with details of all active cases before the Court, listing the parties and their lawyers, summarising the facts and identifying the legal issues raised. It identifies cases in which issues of general importance have been or will be decided, with the expressed purpose being to assist earthquake litigants and those contemplating litigation and to facilitate communication among parties and lawyers. This paper will posit the Earthquake List as an attempt to implement innovative judging techniques to provide efficient yet just legal processes, and which can be examined from a variety of jurisprudential perspectives. One of these is as a case study in the well-established debate about the dialogic relationship between public decisions and private settlement in the rule of law. Drawing on the work of scholars such as Hazel Genn, Owen Fiss, David Luban, Carrie Menkel-Meadow and Judith Resnik, it will explore the tension between the need to develop the law through the doctrine of precedent and the need to resolve civil disputes fairly, affordably and expeditiously. It will also be informed by the presenter’s personal experience of the interplay between reported decisions and private settlement in post-earthquake Christchurch through her work mediating insurance disputes. From a methodological perspective, this research project itself gives rise to issues suitable for discussion at the Law and Society Annual Meeting. These include the challenges in empirical study of judges, working with data collected by the courts and statistical analysis of the legal process in reference to settlement. September 2015 marked the five-year anniversary of the first Christchurch earthquake. There remains widespread dissatisfaction amongst Christchurch residents with the ongoing delays in resolving claims, particularly insurers, and the rebuild process. There will continue to be challenges in Christchurch for years to come, both from as-yet unresolved claims but also because of the possibility of a new wave of claims arising from poor quality repairs. Thus, a final purpose of presenting this paper at the 2016 Meeting is to gain the benefit of other scholarly perspectives and experiences of innovative judging best practice, with a view to strengthening and improving the judicial processes in Christchurch. This Annual Meeting of the Law and Society Association in New Orleans is a particularly appropriate forum for this paper, given the recent ten year anniversary of Hurricane Katrina and the plenary session theme of “Natural and Unnatural Disasters – human crises and law’s response.” The presenter has a personal connection with this theme, as she was a Fulbright scholar from New Zealand at New York University in 2005/2006 and participated in the student volunteer cleanup effort in New Orleans following Katrina. http://www.lawandsociety.org/NewOrleans2016/docs/2016_Program.pdf
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.
Eccentrically Braced Frames (EBFs) are a widely used seismic resisting structural steel system. Since their inception in the late 1970s, they have been a viable option with an available stiffness that is between simple braced systems and moment resisting systems. A similar concept, the linked column frame (LCF), uses shear links between two closely spaced columns. In both cases, the key component is the active link or the shear link, and this component is the objective of this study. The performance of high rise EBF buildings in the 2010 and 2011 Christchurch earthquakes was beyond that which was expected, especially considering the very high accelerations recorded. As the concrete high-rises were torn down, two EBF buildings remained standing and only required some structural repair. These events prompted a renewed interest in bolted shear links, as well as their performance. While some research into replaceable shear links had already been done (Mansour, 2011), the objectives of this study were to improve on the shear link itself, with the consideration that links built in the future are likely to be bolted. The main components of this study were to: 1. Reduce or eliminate the requirements for intermediate web stiffeners, as they were suspected of being detrimental to performance. Furthermore, any reduction in stiffening requirements is a direct fabrication cost saving. Links with low web aspect ratios were found to achieve exceptional ductilities when no stiffeners were included, prompting new design equations. 2. Ensure that the stresses in the ends of links are adequately transferred into the endplates without causing fractures. Although most of the experimental links had web doubler plates included, four had varied lengths of such doubler plates from 0.0 in. to 8.0 in. The link without any doubler plates performed to a similar level to its peers, and thus it is likely that links with quality end details may not need web doubler plates at all. 3. Evaluate the performance of a link with double sided stiffeners without the use of web welds, as opposed to conventional single sided, welded stiffeners. This link performed well, and web-weld-less double sided stiffeners may be an economical alternative to conventional stiffeners for deeper sections of links. 4. Evaluate the performance of a link with thin endplates that are made efficient with the use of gusset plates. This link performed to an acceptable level and provides evidence for a cost effective alternative to thick endplates, especially considering the high overstrength end moments in links, typically requiring 16-bolt connections. 5. Examine the potential use of an alternative EBF arrangement where the collector beam is over sized, and the link section is formed by cutting out parts of the beam's web. After running a series of finite element models each with a unique variation, a number of approximate design rules were derived such that future research could develop this idea further experimentally. 6. Ensure that during testing, the secondary elements (members that are not the shear link), do not yield and are not close to yielding. None of the instrumented elements experienced any unexpected yielding, however the concerns for high stresses in the collector beam panel zone during design were warranted. The use of an existing New Zealand design equation is recommended as an extra check for design codes worldwide. The above objectives were mainly conducted experimentally, except: the data set for item 1 was greatly expanded through the use of a calibrated numerical model which was then used in an extensive parametric study; item 5 was purely finite element based; and, a small parametric study was included for item 3 in an attempt to expand on the trends found there.
Advocates for Compact City, Smart Growth and New Urbanism claim intensification of land use as a means to achieve sustainability imperatives, manage urbanisation and curb peripheral sprawl. It appears policy makers and planners have taken this perspective into consideration over the last two decades as intensification appears more prevalent in policy and planning. Literature points to residential infill as a method of providing for housing development within city limits. While residential infill is recognised in literature, little is known about what it consists of and the different stakeholders involved. This study will document different types of infill, identify various stakeholders associated with the different types and how their roles align and conflict.
The Canterbury region of New Zealand was shaken by major earthquakes on the 4th September 2010 and 22nd February 2011. The quakes caused 185 fatalities and extensive land, infrastructure and building damage, particularly in the Eastern suburbs of Christchurch city. Almost 450 ha of residential and public land was designated as a ‘Red Zone’ unsuitable for residential redevelopment because land damage was so significant, engineering solutions were uncertain, and repairs would be protracted. Subsequent demolition of all housing and infrastructure in the area has left a blank canvas of land stretching along the Avon River corridor from the CBD to the sea. Initially the Government’s official – but enormously controversial – position was that this land would be cleared and lie fallow until engineering solutions could be found that enabled residential redevelopment. This paper presents an application of a choice experiment (CE) that identified and assessed Christchurch residents’ preferences for different land use options of this Red Zone. Results demonstrated strong public support for the development of a recreational reserve comprising a unique natural environment with native fauna and flora, healthy wetlands and rivers, and recreational opportunities that align with this vision. By highlighting the value of a range of alternatives, the CE provided a platform for public participation and expanded the conversational terrain upon which redevelopment policy took place. We conclude the method has value for land use decision-making beyond the disaster recovery context.
This paper identifies and analyses the networks of support for tangata whaiora (mental health clients) utilising a kaupapa Mäori health service following the Ötautahi/Christchurch earthquakes in Aotearoa New Zealand from 2010 to 2012. Semi- structured interviews were undertaken with 39 participants, comprising clients (Mäori and Päkehä), staff, managers and board members of a kaupapa Mäori provider in the city. Selected quotes are presented alongside a social network analysis of the support accessed by all participants. Results show the signifi cant isolation of both Mäori and Päkehä mental health clients post- disaster and the complexity of individuals and collectives dealing with temporally and spatially overlapping hazards and disasters at personal, whänau and community level.
Liquefaction features and the geologic environment in which they formed were carefully studied at two sites near Lincoln in southwest Christchurch. We undertook geomorphic mapping, excavated trenches, and obtained hand cores in areas with surficial evidence for liquefaction and areas where no surficial evidence for liquefaction was present at two sites (Hardwick and Marchand). The liquefaction features identified include (1) sand blows (singular and aligned along linear fissures), (2) blisters or injections of subhorizontal dikes into the topsoil, (3) dikes related to the blows and blisters, and (4) a collapse structure. The spatial distribution of these surface liquefaction features correlates strongly with the ridges of scroll bars in meander settings. In addition, we discovered paleoliquefaction features, including several dikes and a sand blow, in excavations at the sites of modern liquefaction. The paleoliquefaction event at the Hardwick site is dated at A.D. 908-1336, and the one at the Marchand site is dated at A.D. 1017-1840 (95% confidence intervals of probability density functions obtained by Bayesian analysis). If both events are the same, given proximity of the sites, the time of the event is A.D. 1019-1337. If they are not, the one at the Marchand site could have been much younger. Taking into account a preliminary liquefaction-triggering threshold of equivalent peak ground acceleration for an Mw 7.5 event (PGA7:5) of 0:07g, existing magnitude-bounded relations for paleoliquefaction, and the timing of the paleoearthquakes and the potential PGA7:5 estimated for regional faults, we propose that the Porters Pass fault, Alpine fault, or the subduction zone faults are the most likely sources that could have triggered liquefaction at the study sites. There are other nearby regional faults that may have been the source, but there is no paleoseismic data with which to make the temporal link.
Creative temporary or transitional use of vacant urban open spaces is seldom foreseen in traditional urban planning and has historically been linked to economic or political disturbances. Christchurch, like most cities, has had a relatively small stock of vacant spaces throughout much of its history. This changed dramatically after an earthquake and several damaging aftershocks hit the city in 2010 and 2011; temporary uses emerged on post-earthquake sites that ran parallel to the “official” rebuild discourse and programmes of action. The paper examines a post-earthquake transitional community-initiated open space (CIOS) in central Christchurch. CIOS have been established by local community groups as bottom-up initiatives relying on financial sponsorship, agreements with local landowners who leave their land for temporary projects until they are ready to redevelop, and volunteers who build and maintain the spaces. The paper discusses bottom-up governance approaches in depth in a single temporary post-earthquake community garden project using the concepts of community resilience and social capital. The study analyses and highlights the evolution and actions of the facilitating community organisation (Greening the Rubble) and the impact of this on the project. It discusses key actors’ motivations and values, perceived benefits and challenges, and their current involvement with the garden. The paper concludes with observations and recommendations about the initiation of such projects and the challenges for those wishing to study ephemeral social recovery phenomena.
Purpose - The purpose of this paper is to identify through the application of Actor Network Theory (ANT) the issues and impediments to the implementation of mandatory seismic retrofitting policies proposed by the New Zealand Government. In particular the tension between the heritage protection objectives contained in the Resource Management Act 1991 and the earthquake mitigation measures contained in the Building Act 2004 are examined. Design/methodology/approach - The paper uses a case study approach based on the Harcourts Building in Wellington New Zealand and the case law relating to attempts to demolish this particular building. Use is made of ANT as a 'lens' to identify and study the controversies around mandatory seismic retrofitting of heritage buildings. The concept of translation is used to draw network diagrams.
The majority of current procedures used to deduce liquefaction potential of soils rely on empirical methods. These methods have been proven to work in the past, but these methods are known to overestimate the liquefaction potential in certain regions of Christchurch due to a whole range of factors, and the theoretical basis behind these methods cannot be explained scientifically. Critical state soil mechanics theory was chosen to provide an explanation for the soil's behaviour during the undrained shearing. Soils from two sites in Christchurch were characterised at regular intervals for the critical layers and tested for the critical state lines (CSL). Various models and relationships were then used to predict the CSL and compared with the actual CSL. However none of the methods used managed to predict the CSL accurately, and a separate Christchurch exclusive relationship was proposed. The resultant state parameter values could be obtained from shear-wave velocity plots and were then developed into cyclic resistance ratios (CRR). These were subsequently compared with cyclic stress ratios (CSR) from recent Christchurch earthquakes to obtain the factor of safety. This CSL-based approach was compared with other empirical methods and was shown to yield a favourable relationship with visual observations at the sites' locations following the earthquake.
"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
This project looks at how destroyed architecture, although physically lost, fundamentally continues to exist within human memories as a non-physical entity. The site chosen is Avonside Girls’ High School in Christchurch, New Zealand, a school heavily damaged during the February 22nd earthquake in 2011. The project focuses on the Main Block, a 1930s masonry building which had always been a symbol for the school and its alumni. The key theories relevant to this are studies on non-material architecture and memory as these subjects investigate the relationship between conceptual idea and the triggering of it. This research aims to study how to fortify a thought-based architecture against neglect, similar to the retrofitting of physical structures. In doing so, the importance of the emotive realm of architecture and the idea behind a building (as opposed to the built component itself) is further validated, promoting more broadminded stances regarding the significance of the idea over the object. A new method for disaster recovery and addressing trauma from lost architecture is also acquired. Factors regarding advanced structural systems and programmes are not covered within the scope of this research because the project instead explores issues regarding the boundaries between the immaterial and material. The project methodology involves communicating a narrative derived from the memories alumni and staff members have of the old school block. The approach for portraying the narrative is based on a list of strategies obtained from case studies. The final product of the research is a new design for the high school, conveyed through a set of atmospheric drawings that cross-examines the boundaries between the physical and non-physical realms by representing the version of the school that exists solely within memories.
Liquefaction-induced lateral spreading in large seismic events often results in pervasive and costly damage to engineering structures and lifelines, making it a critical component of engineering design. However, the complex nature of this phenomenon leads to designing for such a hazard extremely challenging and there is a clear for an improved understanding and predicting liquefaction-induced lateral spreading. The 2010-2011 Canterbury (New Zealand) Earthquakes triggered severe liquefaction-induced lateral spreading along the streams and rivers of the Christchurch region, causing extensive damage to roads, bridges, lifelines, and structures in the vicinity. The unfortunate devastation induced from lateral spreading in these events also rendered the rare opportunity to gain an improved understanding of lateral spreading displacements specific to the Christchurch region. As part of this thesis, the method of ground surveying was employed following the 4 September 2010 Darfield (Mw 7.1) and 22 February 2011 Christchurch (Mw 6.2) earthquakes at 126 locations (19 repeated) throughout Christchurch and surrounding suburbs. The method involved measurements and then summation of crack widths along a specific alignment (transect) running approximately perpendicular to the waterway to indicate typically a maximum lateral displacement at the bank and reduction of the magnitude of displacements with distance from the river. Rigorous data processing and comparisons with alternative measurements of lateral spreading were performed to verify results from field observations and validate the method of ground surveying employed, as well as highlight the complex nature of lateral spreading displacements. The welldocumented field data was scrutinized to gain an understanding of typical magnitudes and distribution patterns (distribution of displacement with distance) of lateral spreading observed in the Christchurch area. Maximum displacements ranging from less than 10 cm to over 3.5 m were encountered at the sites surveyed and the area affected by spreading ranged from less than 20 m to over 200 m from the river. Despite the highly non-uniform displacements, four characteristic distribution patterns including large, distributed ground displacements, block-type movements, large and localized ground displacements, and areas of little to no displacements were identified. Available geotechnical, seismic, and topographic data were collated at the ground surveying sites for subsequent analysis of field measurements. Two widely-used empirical models (Zhang et al. (2004), Youd et al. (2002)) were scrutinized and applied to locations in the vicinity of field measurements for comparison with model predictions. The results indicated generally poor correlation (outside a factor of two) with empirical predictions at most locations and further validated the need for an improved, analysis- based method of predicting lateral displacements that considers the many factors involved on a site-specific basis. In addition, the development of appropriate model input parameters for the Youd et al. (2002) model led to a site-specific correlation of soil behavior type index, Ic, and fines content, FC, for sites along the Avon River in Christchurch that matched up well with existing Ic – FC relationships commonly used in current practice. Lastly, a rigorous analysis was performed for 25 selected locations of ground surveying measurements along the Avon River where ground slope conditions are mild (-1 to 2%) and channel heights range from about 2 – 4.5 m. The field data was divided into categories based on the observed distribution pattern of ground displacements including: large and distributed, moderate and distributed, small to negligible, and large and localized. A systematic approach was applied to determine potential critical layers contributing to the observed displacement patterns which led to the development of characteristic profiles for each category considered. The results of these analyses outline an alternative approach to the evaluation of lateral spreading in which a detailed geotechnical analysis is used to identify the potential for large spreading displacements and likely spatial distribution patterns of spreading. Key factors affecting the observed magnitude and distribution of spreading included the thickness of the critical layer, relative density, soil type and layer continuity. It was found that the large and distributed ground displacements were associated with a thick (1.5 – 2.5 m) deposit of loose, fine to silty sand (qc1 ~4-7 MPa, Ic 1.9-2.1, qc1n_cs ~50-70) that was continuous along the bank and with distance from the river. In contrast, small to negligible displacements were characterized by an absence of or relatively thin (< 1 m), discontinuous critical layer. Characteristic features of the moderate and distributed displacements were found to be somewhere between these two extremes. The localized and large displacements showed a characteristic critical layer similar to that observed in the large and distributed sites but that was not continuous and hence leading to the localized zone of displacement. The findings presented in this thesis illustrate the highly complex nature of lateral displacements that cannot be captured in simplified models but require a robust geotechnical analysis similar to that performed for this research.
This thesis studies the behaviour of diaphragms in multi-storey timber buildings by providing methods for the estimation of the diaphragm force demand, developing an Equivalent Truss Method for the analysis of timber diaphragms, and experimentally investigating the effects of displacement incompatibilities between the diaphragm and the lateral load resisting system and developing methods for their mitigation. The need to better understand the behaviour of diaphragms in timber buildings was highlighted by the recent 2010-2011 Canterbury Earthquake series, where a number of diaphragms in traditional concrete buildings performed poorly, compromising the lateral load resistance of the structure. Although shortcomings in the estimation of force demand, and in the analysis and design of concrete floor diaphragms have already been partially addressed by other researchers, the behaviour of diaphragms in modern multi-storey timber buildings in general, and in low damage Pres-Lam buildings (consisting of post-tensioned timber members) in particular is still unknown. The recent demand of mid-rise commercial timber buildings of ten storeys and beyond has further highlighted the lack of appropriate methods to analyse timber diaphragms with irregular floor geometries and large spans made of both light timber framing and massive timber panels. Due to the lower stiffness of timber lateral load resisting systems, compared with traditional construction materials, and the addition of in-plane flexible diaphragms, the effect of higher modes on the global dynamic behaviour of a structure becomes more critical. The results from a parametric non-linear time-history analysis on a series of timber frame and wall structures showed increased storey shear and moment demands even for four storey structures when compared to simplistic equivalent static analysis. This effect could successfully be predicted with methods available in literature. The presence of diaphragm flexibility increased diaphragm inter-storey drifts and the peak diaphragm demand in stiff wall structures, but had less influence on the storey shears and moments. Diaphragm force demands proved to be significantly higher than the forces derived from equivalent static analysis, leading to potentially unsafe designs. It is suggested to design all diaphragms for the same peak demand; a simplified approach to estimate these diaphragm forces is proposed for both frame and wall structures. Modern architecture often requires complex floor geometries with long spans leading to stress concentrations, high force demands and potentially large deformations in the diaphragms. There is a lack of guidance and regulation regarding the analysis and design of timber diaphragms and a practical alternative to the simplistic equivalent deep beam analysis or costly finite element modelling is required. An Equivalent Truss Method for the analysis of both light timber framed and massive timber diaphragms is proposed, based on analytical formulations and verified against finite element models. With this method the panel unit shear forces (shear flow) and therefore the fastener demand, chord forces and reaction forces can be evaluated. Because the panel stiffness and fastener stiffness are accounted for, diaphragm deflection, torsional effects and transfer forces can also be assessed. The proposed analysis method is intuitive and can be used with basic analysis software. If required, it can easily be adapted for the use with diaphragms working in the non-linear range. Damage to floor diaphragms resulting from displacement incompatibilities due to frame elongation or out-of plane deformation of walls can compromise the transfer of inertial forces to the lateral load resisting system as well as the stability of other structural elements. Two post-tensioned timber frame structures under quasi-static cyclic and dynamic load, respectively, were tested with different diaphragm panel layouts and connections investigating their ability to accommodate frame elongations. Additionally, a post-tensioned timber wall was loaded under horizontal cyclic loads through two pairs of collector beams. Several different connection details between the wall and the beams were tested, and no damage to the collector beams or connections was observed in any of the tests. To evaluate the increased strength and stiffness due to the wall-beam interaction an analytical procedure is presented. Finally, a timber staircase core was tested under bi-directional loading. Different connection details were used to study the effect of displacement incompatibilities between the orthogonal collector beams. These experiments showed that floor damage due to displacement incompatibilities can be prevented, even with high levels of lateral drift, by the flexibility of well-designed connections and the flexibility of the timber elements. It can be concluded that the flexibility of timber members and the flexibility of their connections play a major role in the behaviour of timber buildings in general and of diaphragms specifically under seismic loads. The increased flexibility enhances higher mode effects and alters the diaphragm force demand. Simple methods are provided to account for this effect on the storey shear, moment and drift demands as well as the diaphragm force demands. The analysis of light timber framing and massive timber diaphragms can be successfully analysed with an Equivalent Truss Method, which is calibrated by accounting for the panel shear and fastener stiffnesses. Finally, displacement incompatibilities in frame and wall structures can be accommodated by the flexibilities of the diaphragm panels and relative connections. A design recommendations chapter summarizes all findings and allows a designer to estimate diaphragm forces, to analyse the force path in timber diaphragms and to detail the connections to allow for displacement incompatibilities in multi-storey timber buildings.