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Research papers, University of Canterbury Library

- The Avon-Ōtākaro Redzone is an 11 kilometer stretch of land along the Avon-Ōtākaro River in Christchurch. - This project focused on the creation of a publicly available biodiversity map of the AvonŌtākaro River Corridor, a project undertaken as part of the ecological restoration of the Christchurch redzone. - This project originated from the Christchurch 2010-2011 earthquake sequence which saw liquefaction damage along 11km of the Avon River. Under guidance from The Nature Lab & Ōtākaro Living Laboratory, and various other experts, the primary research objective was to map historical biodiversity, identify hotspots, and assess areas for potential revegetation. - The data collected came from historical black maps, current iNaturalist data, and soil classification information. - The findings show that, pre-colonialism, the area was composed of herbaceous areas, wetlands, native shrubland, and tussock land, with key plants such as river, fern, tutu, and cabbage trees. - The post-earthquake analysis shows a transition from a residential area to patchy grasslands and swampy areas. - The findings also showed a strong relationship between historic sites and soil classifications, providing knowledge for past and future vegetation patterns and spread. - This map will be a valuable resource for conservation efforts and public engagement as the area transitions into a blue-green corridor.

Research papers, University of Canterbury Library

An extensive research program is on-going at the University of Canterbury, New Zealand to develop new technologies to permit the construction of multi-storey timber buildings in earthquake prone areas. The system combines engineered timber beams, columns and walls with ductile moment resisting connections using post-tensioned tendons and eventually energy dissipaters. The extensive experimental testing on post-tensioned timber building systems has proved a remarkable lateral response of the proposed solutions. A wide number of post-tensioned timber subassemblies, including beam-column connections, single or coupled walls and column-foundation connections, have been analysed in static or quasi-static tests. This contribution presents the results of the first dynamic tests carried out with a shake-table. Model frame buildings (3-storey and 5-storey) on one-quarter scale were tested on the shake-table to quantify the response of post-tensioned timber frames during real-time earthquake loading. Equivalent viscous damping values were computed for post-tensioned timber frames in order to properly predict their response using numerical models. The dynamic tests were then complemented with quasi-static push and pull tests performed to a 3-storey post-tensioned timber frame. Numerical models were included to compare empirical estimations versus dynamic and quasi-static experimental results. Different techniques to model the dynamic behaviour of post-tensioned timber frames were explored. A sensitivity analysis of alternative damping models and an examination of the influence of designer choices for the post-tensioning force and utilization of column armouring were made. The design procedure for post-tensioned timber frames was summarized and it was applied to two examples. Inter-storey drift, base shear and overturning moments were compared between numerical modelling and predicted/targeted design values.

Research papers, University of Canterbury Library

A linear and non-linear model are developed to analyze the structural impact and response of two single degree of freedom structures, representing adjacent buildings or bridge sections. Different impact coefficients of restitution, normalized distances between structures and a range of different structural periods are considered. The probability of impact and the displacement changes that can result from these collisions are computed. The likelihood of an increase in displacement is quantified in a probabilistic sense. A full matrix of response simulations are performed to individually investigate and delineate the effects of inter-structure gap-ratio, period ratios, structural non-linearity and impact elasticity. Column inelasticity is incorporated through the use of a Ramberg-Osgood type hysteresis rule. The minimum normalized distance, or gap-ratio, required between two structures to ensure that the likelihood of increased displacement of more than 10% for either structure for 90% of the given earthquake ground motions is assessed as one of many possible design risk bounds. Increased gap ratio, defined as a percentage of spectral displacement, is shown to reduce the likelihood of impact, as well as close structural periods. Larger differences in the relative periods of the two structures were seen to significantly increase the likelihood of impact. Inclusion of column inelasticity and higher plasticity of impact reduce displacement increases from impact and thus possible further damage to the structures. Such information can be used as a guideline to manage undesirable effects of impact in design - a factor that has been observed to be very important during the recent Canterbury, New Zealand Earthquakes.

Research papers, University of Canterbury Library

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.

Research Papers, Lincoln University

The earthquakes that struck Ōtautahi/Christchurch began September 2010 and continued throughout2012 with the worse shock being February 22, 2011. The extended ‘seismic event’ radically altered thegeophysical and socio-cultural environments of the city. This working paper presents a broad array of datadescribing the impacts of the disaster on Māori. These data frame the results of small email surveyconducted 18 months after the most destructive February 22, 2011. This survey followed two projectsinvestigating the resilience of Māori to the disaster (Lambert & Mark-Shadbolt, 2011; Lambert & Mark-Shadbolt, 2012; Lambert, Mark-Shadbolt, Ataria, & Black, 2012). Results show that while the termresilience has become common to the point of cliché, the Māori experience thus far is best described asendurance.

Research papers, University of Canterbury Library

Cities need places that contribute to quality of life, places that support social interaction. Wellbeing, specifically, community wellbeing, is influenced by where people live, the quality of place is important and who they connect with socially. Social interaction and connection can come from the routine involvement with others, the behavioural acts of seeing and being with others. This research consisted of 38 interviews of residents of Christchurch, New Zealand, in the years following the 2010-12 earthquakes. Residents were asked about the place they lived and their interactions within their community. The aim was to examine the role of neighbourhood in contributing to local social connections and networks that contribute to living well. Specifically, it focused on the role and importance of social infrastructure in facilitating less formal social interactions in local neighbourhoods. It found that neighbourhood gathering places and bumping spaces can provide benefit for living well. Social infrastructure, like libraries, parks, primary schools, and pubs are some of the places of neighbourhood that contributed to how well people can encounter others for social interaction. In addition, unplanned interactions were facilitated by the existence of bumping places, such as street furniture. The wellbeing value of such spaces needs to be acknowledged and factored into planning decisions, and local rules and regulations need to allow the development of such spaces.

Research papers, University of Canterbury Library

Previous earthquakes demonstrated destructive effects of soil-structure interaction on structural response. For example, in the 1970 Gediz earthquake in Turkey, part of a factory was demolished in a town 135 km from the epicentre, while no other buildings in the town were damaged. Subsequent investigations revealed that the fundamental period of vibration of the factory was approximately equal to that of the underlying soil. This alignment provided a resonance effect and led to collapse of the structure. Another dramatic example took place in Adapazari, during the 1999 Kocaeli earthquake where several foundations failed due to either bearing capacity exceedance or foundation uplifting, consequently, damaging the structure. Finally, the Christchurch 2012 earthquakes have shown that significant nonlinear action in the soil and soil-foundation interface can be expected due to high levels of seismic excitation and spectral acceleration. This nonlinearity, in turn, significantly influenced the response of the structure interacting with the soil-foundation underneath. Extensive research over more than 35 years has focused on the subject of seismic soil-structure interaction. However, since the response of soil-structure systems to seismic forces is extremely complex, burdened by uncertainties in system parameters and variability in ground motions, the role of soil-structure interaction on the structural response is still controversial. Conventional design procedures suggest that soil-structure interaction effects on the structural response can be conservatively ignored. However, more recent studies show that soil-structure interaction can be either beneficial or detrimental, depending on the soil-structure-earthquake scenarios considered. In view of the above mentioned issues, this research aims to utilise a comprehensive and systematic probabilistic methodology, as the most rational way, to quantify the effects of soil-structure interaction on the structural response considering both aleatory and epistemic uncertainties. The goal is achieved by examining the response of established rheological single-degree-of-freedom systems located on shallow-foundation and excited by ground motions with different spectral characteristics. In this regard, four main phases are followed. First, the effects of seismic soil-structure interaction on the response of structures with linear behaviour are investigated using a robust stochastic approach. Herein, the soil-foundation interface is modelled by an equivalent linear cone model. This phase is mainly considered to examine the influence of soil-structure interaction on the approach that has been adopted in the building codes for developing design spectrum and defining the seismic forces acting on the structure. Second, the effects of structural nonlinearity on the role of soil-structure interaction in modifying seismic structural response are studied. The same stochastic approach as phase 1 is followed, while three different types of structural force-deflection behaviour are examined. Third, a systematic fashion is carried out to look for any possible correlation between soil, structural, and system parameters and the degree of soil-structure interaction effects on the structural response. An attempt is made to identify the key parameters whose variation significantly affects the structural response. In addition, it is tried to define the critical range of variation of parameters of consequent. Finally, the impact of soil-foundation interface nonlinearity on the soil-structure interaction analysis is examined. In this regard, a newly developed macro-element covering both material and geometrical soil-foundation interface nonlinearity is implemented in a finite-element program Raumoko 3D. This model is then used in an extensive probabilistic simulation to compare the effects of linear and nonlinear soil-structure interaction on the structural response. This research is concluded by reviewing the current design guidelines incorporating soil-structure interaction effects in their design procedures. A discussion is then followed on the inadequacies of current procedures based on the outcomes of this study.

Research Papers, Lincoln University

This research investigates creativity in a post-disaster setting. The data explore creativity at the intersection of the affected community of Christchurch, New Zealand and the social processes that followed the earthquakes of 2010 - 2012. Personal and contextual influences on creative ideas implemented for community or commercial benefit are also examined. Viewed as creative, unique approaches to post-disaster problem solving were celebrated locally, nationally and internationally (Bergman, 2014; Wesener, 2015; Cloke & Conradson, 2018). Much has been written about creativity, particularly creativity in organisations and in business. However, little is known with regards to who creates after a disaster, why individuals choose to do so and what impact the post-disaster context has on their creative activity. This exploratory study draws on the literature from the fields of creativity, disasters, psychology, sociology and entrepreneurship to interpret first-hand accounts of people who acted on creative ideas in a physically and socially altered environment. A mixed method - albeit predominantly qualitative - approach to data gathering was adopted that included interviews (n=45) with participants who had been the primary drivers of creative ideas implemented in Christchurch after September 2010 – the first major (7.1 magnitude) earthquake in a prolonged sequence of thousands of aftershocks. Key findings include that a specific type of creativity results from the ‘collision’ between individuals and social processes activated by a disaster situation. This type of creativity could be best categorised as ‘little c’ or socially adaptive and emerges through a prosocial filter. There is wide consensus amongst creativity researchers - principally social psychologists - that for output to be considered creative it must be both novel and useful (Runco & Jaegar, 2012). There is greater tolerance for the novelty component after a disaster as novelty itself has greater utility, either as a distraction or because alternatives are few. Existing creativity models show context as input – an additional component of the creative process – but after a disaster the event itself becomes the catalyst for social processes that result in the creativity seen. Most participants demonstrated characteristics commonly associated with creativity and could be categorised as either a ‘free thinker’ and/or an ‘opportunist’. Some appear preadapted to create and thrive in unstable circumstances. Findings from participants’ completion of a Ten Item Personality Inventory (TIPI) showed an apparent reduced need for extraversion in relation to implementing creative ventures in society. This factor, along with higher levels of agreeableness may indicate a potentially detrimental effect on the success of creative ideas established after a disaster, despite earnest intentions. Three new models are presented to illustrate the key findings of this study. The models imply that disasters enhance both the perceived value of creativity and the desire to act creatively for prosocial ends. The models also indicate that these disaster influenced changes are likely to be temporary.

Images, Alexander Turnbull Library

Four cartoons in the same frame commenting on news and happenings in the week ending 15 December 2011. The cartoons refer to the expulsion of the controversial Member of Parliament, Brendan Horan, from the New Zealand First Party by its leader, Winston Peters; the stereotyping of New Zealand as being 'Middle Earth' following the filming of 'The Hobbit', punned as 'The Habbit'; the lax attitude to building design and standards, which led to the CTV Building disaster in the Christchurch earthquake; the news about the New Zealand SPCA teaching dogs to drive. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

The text 'Rugby World Cup' runs across the top of the cartoon. Below is a poster depicting the shape of a rugby ball with a double koru design and the year '2011'. It is accompanied by the words 'Rugby New Zealand (well not quite all New Zealand)' Someone off screen kicks a rugby ball that represents 'Christrch' across the frame. Context - Christchurch has been told that they will not be able to host any Rugby World Cup games because of the damage to the city after the earthquakes 4 September 2010 and 22 February 2011. Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

“much of what we know about leadership is today redundant because it is literally designed for a different operating model, a different context, a different time” (Pascale, Sternin, & Sternin, p. 4). This thesis describes a project that was designed with a focus on exploring ways to enhance leadership capacity in non-government organisations operating in Christchurch, New Zealand. It included 20 CEOs, directors and managers from organisations that cover a range of settings, including education, recreation, and residential and community therapeutic support; all working with adolescents. The project involved the creation of a peer-supported professional learning community that operated for 14 months; the design and facilitation of which was informed by the Appreciative Inquiry principles of positive focus and collaboration. At the completion of the research project in February 2010, the leaders decided to continue their collective processes as a self-managing and sustaining professional network that has grown and in 2014 is still flourishing under the title LYNGO (Leaders of Youth focussed NGOs). Two compelling findings emerged from this research project. The first of these relates to efficacy of a complexity thinking framework to inform the actions of these leaders. The leaders in this project described the complexity thinking framework as the most relevant, resonant and dynamic approach that they encountered throughout the research project. As such this thesis explores this complexity thinking informed leadership in detail as the leaders participating in this project believed it offers an opportune alternative to more traditional forms of positional leadership and organisational approaches. This exploration is more than simply a rationale for complexity thinking but an iterative in-depth exploration of ‘complexity leadership in action’ which in Chapter 6 elaborates on detailed leadership tools and frameworks for creating the conditions for self-organisation and emergence. The second compelling finding relates to efficacy of Appreciative Inquiry as an emergent research and development process for leadership learning. In particular the adoption of two key principles; positive focus and inclusivity were beneficial in guiding the responsive leadership learning process that resulted in a professional learning community that exhibited high engagement and sustainability. Additionally, the findings suggest that complexity thinking not only acts as a contemporary framework for adaptive leadership of organisations as stated above; but that complexity thinking has much to offer as a framework for understanding leadership development processes through the application of Appreciative Inquiry (AI)-based principles. A consideration of the components associated with complexity thinking has promise for innovation and creativity in the development of leaders and also in the creation of networks of learning. This thesis concludes by suggesting that leaders focus on creating hybrid organisations, ones which leverage the strengths (and minimise the limitations) of self-organising complexity-informed organisational processes, while at the same time retaining many of the strengths of more traditional organisational management structures. This approach is applied anecdotally to the place where this study was situated: the post-earthquake recovery of Christchurch, New Zealand.

Research papers, University of Canterbury Library

Probabilistic Structural Fire Engineering (PSFE) has been introduced to overcome the limitations of current conventional approaches used for the design of fire-exposed structures. Current structural fire design investigates worst-case fire scenarios and include multiple thermal and structural analyses. PSFE permits buildings to be designed to a level of life safety or economic loss that may occur in future fire events with the help of a probabilistic approach. This thesis presents modifications to the adoption of a Performance-Based Earthquake Engineering (PBEE) framework in Probabilistic Structural Fire Engineering (PSFE). The probabilistic approach runs through a series of interrelationships between different variables, and successive convolution integrals of these interrelationships result in probabilities of different measures. The process starts with the definition of a fire severity measure (FSM), which best relates fire hazard intensity with structural response. It is identified by satisfying efficiency and sufficiency criteria as described by the PBEE framework. The relationship between a fire hazard and corresponding structural response is established by analysis methods. One method that has been used to quantify this relationship in PSFE is Incremental Fire Analysis (IFA). The existing IFA approach produces unrealistic fire scenarios, as fire profiles may be scaled to wide ranges of fire severity levels, which may not physically represent any real fires. Two new techniques are introduced in this thesis to limit extensive scaling. In order to obtain an annual rate of exceedance of fire hazard and structural response for an office building, an occurrence model and an attenuation model for office fires are generated for both Christchurch city and New Zealand. The results show that Christchurch city is 15% less likely to experience fires that have the potential to cause structural failures in comparison to all of New Zealand. In establishing better predictive relationships between fires and structural response, cumulative incident radiation (a fire hazard property) is found to be the most appropriate fire severity measure. This research brings together existing research on various sources of uncertainty in probabilistic structural fire engineering, such as elements affecting post-flashover fire development factors (fuel load, ventilation, surface lining and compartment geometry), fire models, analysis methods and structural reliability. Epistemic uncertainty and aleatory uncertainty are investigated in the thesis by examining the uncertainty associated with modelling and the factors that influence post-flashover development of fires. A survey of 12 buildings in Christchurch in combination with recent surveys in New Zealand produced new statistical data on post-flashover development factors in office buildings in New Zealand. The effects of these parameters on temperature-time profiles are evaluated. The effects of epistemic uncertainty due to fire models in the estimation of structural response is also calculated. Parametric fires are found to have large uncertainty in the prediction of post-flashover fires, while the BFD curves have large uncertainties in prediction of structural response. These uncertainties need to be incorporated into failure probability calculations. Uncertainty in structural modelling shows that the choices that are made during modelling have a large influence on realistic predictions of structural response.

Research papers, University of Canterbury Library

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.

Images, Alexander Turnbull Library

Shows John Key phoning Canterbury Earthquake Recovery Minister Gerry Brownlee during his recent visit to China. Key tells Gerry he has found an architect friend in China who can design the new Christchurch Cathedral. Wider context refers to the debate over the 3 plans recently released for the Cathedral, but also refers to media debate concerning Key's involvement in instances of preferential appointments - in particular, his claim to have forgotten a phone call to his friend Ian Fletcher in which Key suggested Fletcher should apply to become director of the Government Communications Security Bureau. See Stuff, 3 April 2013. Colour and black and white versions available Quantity: 2 digital cartoon(s).

Research papers, Victoria University of Wellington

Heritage buildings are an important element of our urban environments, representing the hope and aspirations of a generation gone, reminding us of our achievements and our identity.  When heritage buildings suffer damage, or fall into disrepair they are either met by one of two extremes; a bulldozer or painstaking repair. If the decision to conserve defeats the bulldozer, current heritage practice favours restoration into a mausoleum-type monument to yesteryear. But what if, rather than becoming a museum, these heritage buildings could live on and become a palimpsest of history? What if the damage was embraced and embodied in the repair?  The Cathedral of the Blessed Sacrament on Barbadoes Street, Christchurch is the case study building for this thesis. Suffering damage in the Canterbury earthquakes of 2010 and 2011, the Cathedral sits in ruin waiting for decisions to be made around how it can be retained for future generations.  This thesis will propose a reconstruction for the Cathedral through the analysis of precedent examples of reconstructing damaged heritage buildings and guided by a heritage framework proposed in this thesis. The employed process will be documented as an alternative method for reconstructing other damaged heritage buildings.

Research papers, University of Canterbury Library

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.

Research papers, University of Canterbury Library

Structural pounding may be defined as the collisions occurring between adjacent dynamically excited structures which lack a sufficient separation gap between them. Extensive theoretical and experimental studies have been conducted to investigate this phenomenon. However, the majority, if not all, of these studies fail to consider the flexibility of the soil upon which these structures are constructed. This study aims to investigate the degree of approximation inherent in previous pounding studies which neglected this important feature. In this study, two aspects of soil flexibility effects on dynamic structural response were investigated: the influence of the supporting soil properties on the individual structures (soil-structure interaction) and the through-soil interaction between the foundations of the adjacent structures. Two structural configurations of reinforced concrete moment-resistant frames were considered: the case of two adjacent twelve-storey frames and the pounding of a twelve- and six-storey frames. Four cases of external excitation were investigated: two actual earthquake records applied from two directions each. A nonlinear inelastic dynamic analysis software package developed at the University of Canterbury has been utilized in this study. Suitable numerical models were developed for the through-soil interaction phenomenon and for the structures, which were designed in accordance to the relevant New Zealand design codes. Soilstructure interaction was represented by means of existing models available in the literature. Various separation gaps were provided and the results were compared with the no pounding case. Storey-level impacts only were considered. The pounding response in which soil flexibility was accounted for was compared to the fixed base response for each of the separation gaps incorporated in this study. A high variation in the results was witnessed, indicating the significance of consideration of soil flexibility effects. In addition, the importance of excitation direction was highlighted in this study. The relative storey accelerations were more dependent on the characteristics of the excitation rather than on the magnitudes of the impact forces. Recommendations were proposed which aim towards the generalization of the results of this study.

Research papers, University of Canterbury Library

In major seismic events, a number of plan-asymmetric buildings which experienced element failure or structural collapse had twisted significantly about their vertical axis during the earthquake shaking. This twist, known as “building torsion”, results in greater demands on one side of a structure than on the other side. The Canterbury Earthquakes Royal Commission’s reports describe the response of a number of buildings in the February 2011 Christchurch earthquakes. As a result of the catastrophic collapse of one multi-storey building with significant torsional irregularity, and significant torsional effects also in other buildings, the Royal Commission recommended that further studies be undertaken to develop improved simple and effective guides to consider torsional effects in buildings which respond inelastically during earthquake shaking. Separately from this, as building owners, the government, and other stakeholders, are planning for possible earthquake scenarios, they need good estimates of the likely performance of both new and existing buildings. These estimates, often made using performance based earthquake engineering considerations and loss estimation techniques, inform decision making. Since all buildings may experience torsion to some extent, and torsional effects can influence demands on building structural and non-structural elements, it is crucial that demand estimates consider torsion. Building seismic response considering torsion can be evaluated with nonlinear time history analysis. However, such analysis involves significant computational effort, expertise and cost. Therefore, from an engineers’ point of view, simpler analysis methods, with reasonable accuracy, are beneficial. The consideration of torsion in simple analysis methods has been investigated by many researchers. However, many studies are theoretical without direct relevance to structural design/assessment. Some existing methods also have limited applicability, or they are difficult to use in routine design office practice. In addition, there has been no consensus about which method is best. As a result, there is a notable lack of recommendations in current building design codes for torsion of buildings that respond inelastically. There is a need for building torsion to be considered in yielding structures, and for simple guidance to be developed and adopted into building design standards. This study aims to undertaken to address this need for plan-asymmetric structures which are regular over their height. Time history analyses are first conducted to quantify the effects of building plan irregularity, that lead to torsional response, on the seismic response of building structures. Effects of some key structural and ground motion characteristics (e.g. hysteretic model, ground motion duration, etc.) are considered. Mass eccentricity is found to result in rather smaller torsional response compared to stiffness/strength eccentricity. Mass rotational inertia generally decreases the torsional response; however, the trend is not clearly defined for torsionally restrained systems (i.e. large λty). Systems with EPP and bilinear models have close displacements and systems with Takeda, SINA, and flag-shaped models yield almost the same displacements. Damping has no specific effect on the torsional response for the single-storey systems with the unidirectional eccentricity and excitation. Displacements of the single-storey systems subject to long duration ground motion records are smaller than those for short duration records. A method to consider torsional response of ductile building structures under earthquake shaking is then developed based on structural dynamics for a wide range of structural systems and configurations, including those with low and high torsional restraint. The method is then simplified for use in engineering practice. A novel method is also proposed to simply account for the effects of strength eccentricity on response of highly inelastic systems. A comparison of the accuracy of some existing methods (including code-base equivalent static method and model response spectrum analysis method), and the proposed method, is conducted for single-storey structures. It is shown that the proposed method generally provides better accuracy over a wide range of parameters. In general, the equivalent static method is not adequate in capturing the torsional effects and the elastic modal response spectrum analysis method is generally adequate for some common parameters. Record-to-record variation in maximum displacement demand on the structures with different degrees of torsional response is considered in a simple way. Bidirectional torsional response is then considered. Bidirectional eccentricity and excitation has varying effects on the torsional response; however, it generally increases the weak and strong edges displacements. The proposed method is then generalized to consider the bidirectional torsion due to bidirectional stiffness/strength eccentricity and bidirectional seismic excitation. The method is shown to predict displacements conservatively; however, the conservatism decreases slightly for cases with bidirectional excitation compared to those subject to unidirectional excitation. In is shown that the roof displacement of multi-storey structures with torsional response can be predicted by considering the first mode of vibration. The method is then further generalized to estimate torsional effects on multi-storey structure displacement demands. The proposed procedure is tested multi-storey structures and shown to predict the displacements with a good accuracy and conservatively. For buildings which twist in plan during earthquake shaking, the effect of P-Δλ action is evaluated and recommendations for design are made. P-Δλ has more significant effects on systems with small post- yield stiffness. Therefore, system stability coefficient is shown not to be the best indicator of the importance of P-Δλ and it is recommended to use post-yield stiffness of system computed with allowance for P-Δλ effects. For systems with torsional response, the global system stability coefficient and post- yield stiffness ration do not reflect the significance of P-Δλ effects properly. Therefore, for torsional systems individual seismic force resisting systems should be considered. Accuracy of MRSA is investigated and it is found that the MRSA is not always conservative for estimating the centre of mass and strong edge displacements as well as displacements of ductile systems with strength eccentricity larger than stiffness eccentricity. Some modifications are proposed to get the MRSA yields a conservative estimation of displacement demands for all cases.

Research papers, University of Canterbury Library

Natural hazard reviews reveal increases in disaster impacts nowhere more pronounced than in coastal settlements. Despite efforts to enhance hazard resilience, the common trend remains to keep producing disaster prone places. This paper explicitly explores hazard versus multi-hazard concepts to illustrate how different conceptualizations can enhance or reduce settlement resilience. Understandings gained were combined with onthe-ground lessons from earthquake and flooding experiences to develop of a novel ‘first cut’ approach for analyzing key multi-hazard interconnections, and to evaluate resilience enhancing opportunities. Traditional disaster resilience efforts often consider different hazard types discretely. However, recent events in Christchurch, a New Zealand city that is part of the 100 Resilient Cities network, highlight the need to analyze the interrelated nature of different hazards, especially for enhancing lifelines system resilience. Our overview of the Christchurch case study demonstrates that seismic, hydrological, shallow-earth, and coastal hazards can be fundamentally interconnected, with catastrophic results where such interconnections go unrecognized. In response, we have begun to develop a simple approach for use by different stakeholders to support resilience planning, pre and post disaster, by: drawing attention to natural and built environment multi-hazard links in general; illustrating a ‘first cut’ tool for uncovering earthquake-flooding multi-hazard links in particular; and providing a basis for reviewing resilience strategy effectiveness in multi-hazard prone environments. This framework has particular application to tectonically active areas exposed to climate-change issues.

Research Papers, Lincoln University

The major earthquakes of 2010 and 2011 brought to an abrupt end a process of adaptive reuse, revitalisation and gentrification that was underway in the early 20th century laneways and buildings located in the south eastern corner of the Christchurch Central Business District. Up until then, this location was seen as an exemplar of how mixed use could contribute to making the central city an attractive and viable alternative to the suburban living experience predominant in New Zealand. This thesis is the result of a comprehensive case study of this “Lichfield Lanes” area, which involved in depth interviews with business owners, observation of public meetings and examination of documents and the revitalisation research literature. Findings were that many of the factors seen to make this location successful pre-earthquakes mirror the results of similar research in other cities. These factors include: the importance of building upon historic architecture and the eclectic spaces this creates; a wide variety of uses generating street life; affordable rental levels; plus the dangers of uniformity of use brought about by focussing on business types that pay the most rent. Also critical is co-operation between businesses to create and effectively market and manage an identifiable precinct that has a coherent style and ambience that differentiates the location from competing suburban malls. In relation to the latter, a significant finding of this project was that the hospitality and retail businesses key to the success of Lichfield Lanes were not typical and could be described as quirky, bohemian, chaotic, relatively low rent, owner operated and appealing to the economically important “Creative Class” identified by Richard Florida (2002) and others. In turn, success for many of these businesses can be characterised as including psychological and social returns rather than simply conventional economic benefits. This has important implications for inner city revitalisation, as it contrasts with the traditional focus of local authorities and property developers on physical aspects and tenant profitability as measures of success. This leads on to an important conclusion from this research, which is that an almost completely inverted strategy from that applied to suburban mall development, may be most appropriate for successful inner city revitalisation. It also highlights a disconnection between the focus and processes of regulatory authorities and the outcomes and processes most acceptable to the people likely to frequent the central city. Developers are often caught in the middle of this conflicted situation. Another finding was early commitment by businesses to rebuild the case study area in the same style, but over time this waned as delay, demolition, insurance problems, political and planning uncertainty plus other issues made participation by the original owners and tenants impossible or uneconomic. In conclusion, the focus of inner city revitalisation is too often on buildings rather than the people that use them and what they now desire from the central city.

Research papers, University of Canterbury Library

High-Force-to-Volume lead dampers (HF2V) have been recently developed through an experimental research program at University of Canterbury – New Zealand. Testing of the device and applications on beam column joints have demonstrated stable hysteretic behaviour with almost no damage. This paper reports testing of HF2V devices with straight, bulged and constricted shaft configurations subjected to velocities of 0.15 - 5.0mm/s. The effect of the shaft configuration on the hysteresis loop shape, design relationships and the effect of the velocity on the resistive force of the device are described. Results show that hysteresis loop shape of the device is almost square regardless of the shaft configuration, and that devices are characterized by noticeable velocity dependence in the range of 0.15-1.0mm/s.

Research papers, University of Canterbury Library

A preliminary case study assessing the seismic sustainability of two reinforced concrete structures, a frame structure and a wall structure, was conducted to determine which structural system is more seismically sustainable. The two structures were designed to the same standards and were assumed to be located in Christchurch, New Zealand. A component-based probabilistic seismic loss assessment, considering direct losses only, was conducted for two ground motion records, regarded to approximately represent a 1 in 500 year earthquake event and a 1 in 2500 year earthquake event, respectively. It is shown that the wall structure results in lower direct losses than the frame structure in the less severe ground motion scenario. However, in the more severe ground motion scenario, the frame structure results in lower direct losses. Hence, this study demonstrates that which structural system has the lower direct losses depends on the ground motion intensity level.

Research papers, University of Canterbury Library

New Zealand has a long tradition of using light timber frame for construction of its domestic dwellings. After the most recent earthquakes (e.g. Canterbury earthquakes sequence), wooden residential houses showed satisfactory life safety performance which aligns with New Zealand design codes requirements. However, poor performance was reported in terms of their seismic resilience that can be generally associated with community demands. Future expectations of the seismic performance of wooden-framed houses by homeowners were assessed in this research. Homeowners in the Wellington region were asked in a survey about the levels of safety and expected possible damage in their houses after a seismic event. Findings bring questions about whether New Zealand code requirements are good enough to satisfy community demands. Also, questions whether available information of strengthening techniques to structurally prepare wooden-framed houses to face future major earthquakes can help to make homeowners feel safer at home during major seismic events.

Research papers, University of Canterbury Library

Following the 2010/2011 Canterbury earthquakes, approximately 60% of multi-story buildings with reinforced concrete walls required demolition. Both practitioners and researchers have increasingly realized that low-damage structural systems could be an alternative to improve the seismic behaviour of concrete buildings and to reduce the economic and social impact of structural damage in future earthquakes. To verify the seismic response of a low-damage concrete wall building representing state-of-art design practice, a shake table test on a two-story concrete building was recently conducted as part of an ILEE-QuakeCoRE collaborative research program. The building utilized flexible wall-to-floor connections in the long span direction and isolating wall-to-floor devices in the short span direction to provide a comparison of their respective behaviour. Additionally, the wall-to-floor interaction such as effects of wall uplift on the link slab, and force transfer mechanism from floor to the wall will be discussed in this paper.

Images, Alexander Turnbull Library

The title is 'Cardboard cathedral proposed...' The cartoon shows the Christchurch Cathedral completed with cardboard boxes and a spire made of used toilet rolls. A puppy is in the process of unwinding toilet paper from the last roll. On an earlier part of the roof stand cardboard cutouts of the Christchurch wizard and maybe the mayor, Bob Parker. Context: A design for a temporary cathedral has been outlined by renowned Japanese architect Shigeru Ban. The proposed $4 million temporary replacement for Christchurch's destroyed cathedral made of shipping containers and cardboard has been met with scepticism from residents of the quake-hit city who wonder whether another church is really what the city needs right now. (3 News 1 August 2011) Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

A rescue worker carries the dead body of a woman out of the crumbled remains of a building. Nearby is a copy of the 'Building Code'. Context - there are questions being asked about whether some of the buildings that collapsed too readily in the Christchurch earthquake of 22 February 2011 had been subject to stringent enough building code regulations. The Department of Building and Housing said the vertical shaking in the central business district was both extreme and unusual and early indications suggest it was much more violent than designed for in the building code standards which are based on the kind of shaking expected to happen every 500 years. Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

Christchurch City Council (Council) is undertaking the Land Drainage Recovery Programme in order to assess the effects of the earthquakes on flood risk to Christchurch. In the course of these investigations it has become better understood that floodplain management should be considered in a multi natural hazards context. Council have therefore engaged the Jacobs, Beca, University of Canterbury, and HR Wallingford project team to investigate the multihazards in eastern areas of Christchurch and develop flood management options which also consider other natural hazards in that context (i.e. how other hazards contribute to flooding both through temporal and spatial coincidence). The study has three stages:  Stage 1 Gap Analysis – assessment of information known, identification of gaps and studies required to fill the gaps.  Stage 2 Hazard Studies – a gap filling stage with the studies identified in Stage 1.  Stage 3 Collating, Optioneering and Reporting – development of options to manage flood risk. This present report is to document findings of Stage 1 and recommends the studies that should be completed for Stage 2. It has also been important to consider how Stage 3 would be delivered and the gaps are prioritised to provide for this. The level of information available and hazards to consider is extensive; requiring this report to be made up of five parts each identifying individual gaps. A process of identifying information for individual hazards in Christchurch has been undertaken and documented (Part 1) followed by assessing the spatial co-location (Part 2) and probabilistic presence of multi hazards using available information. Part 3 considers multi hazard presence both as a temporal coincidence (e.g. an earthquake and flood occurring at one time) and as a cascade sequence (e.g. earthquake followed by a flood at some point in the future). Council have already undertaken a number of options studies for managing flood risk and these are documented in Part 4. Finally Part 5 provides the Gap Analysis Summary and Recommendations to Council. The key findings of Stage 1 gap analysis are: - The spatial analysis showed eastern Christchurch has a large number of hazards present with only 20% of the study area not being affected by any of the hazards mapped. Over 20% of the study area is exposed to four or more hazards at the frequencies and data available. - The majority of the Residential Red Zone is strongly exposed to multiple hazards, with 86% of the area being exposed to 4 or more hazards, and 24% being exposed to 6 or more hazards. - A wide number of gaps are present; however, prioritisation needs to consider the level of benefit and risks associated with not undertaking the studies. In light of this 10 studies ranging in scale are recommended to be done for the project team to complete the present scope of Stage 3. - Stage 3 will need to consider a number of engineering options to address hazards and compare with policy options; however, Council have not established a consistent policy on managed retreat that can be applied for equal comparison; without which substantial assumptions are required. We recommend Council undertake a study to define a managed retreat framework as an option for the city. - In undertaking Stage 1 with floodplain management as the focal point in a multi hazards context we have identified that Stage 3 requires consideration of options in the context of economics, implementation and residual risk. Presently the scope of work will provide a level of definition for floodplain options; however, this will not be at equal levels of detail for other hazard management options. Therefore, we recommend Council considers undertaking other studies with those key hazards (e.g. Coastal Hazards) as a focal point and identifies the engineering options to address such hazards. Doing so will provide equal levels of information for Council to make an informed and defendable decision on which options are progressed following Stage 3.

Research papers, The University of Auckland Library

The Canterbury earthquakes of 2010 and 2011 generated hundreds of thousands of insurance claims, many of which were disputed. The New Zealand justice system faced the same challenge encountered by other jurisdictions following a natural disaster: how to resolve these disputes quickly and at minimal cost but also fairly, to avoid compounding the disaster with injustice? The thesis is of this article is that although the earthquakes were catastrophic for New Zealand, they also created a unique opportunity to design an innovative civil justice process—the Christchurch High Court Earthquake List—and to test, over a relatively short timeframe, how well that process works. This article describes the Christchurch High Court Earthquake List and analyses it by reference to civil justice theory about the relative normative values of public adjudication and private settlement and the dialogic relationship between them. It then evaluates the List, using statistics available five years on from the earthquakes and by reference to the author’s own experience mediating earthquake disputes.

Research papers, The University of Auckland Library

Unreinforced masonry (URM) buildings have repeatedly been shown to perform poorly in large magnitude earthquakes, with both New Zealand and Australia having a history of past earthquakes that have resulted in fatalities due to collapsed URM buildings. A comparison is presented here of the URM building stock and the seismic vulnerability of Christchurch and Adelaide in order to demonstrate the relevance to Australian cities of observations in Christchurch resulting from the 2010/2011 Canterbury earthquake swarm. It is shown that the materials, architecture and hence earthquake strength of URM buildings in both countries is comparable and that Adelaide and other cities of Australia have seismic vulnerability sufficient to cause major damage to their URM buildings should a design level earthquake occur. Such an earthquake is expected to cause major building damage, and fatalities should be expected.

Research papers, University of Canterbury Library

Over 6.3 million waste tyres are produced annually in New Zealand (Tyrewise, 2021), leading to socioeconomic and environmental concerns. The 2010-11 Canterbury Earthquake Sequence inflicted extensive damage to ~6,000 residential buildings, highlighting the need to improve the seismic resilience of the residential housing sector. A cost-effective and sustainable eco-rubber geotechnical seismic isolation (ERGSI) foundation system for new low-rise buildings was developed by the authors. The ERGSI system integrates a horizontal geotechnical seismic isolation (GSI) layer i.e., a deformable seismic energy dissipative filter made of granulated tyre rubber (GTR) and gravel (G) – and a flexible rubberised concrete raft footing. Geotechnical experimental and numerical investigations demonstrated the effectiveness of the ERGSI system in reducing the seismic demand at the foundation level (i.e., reduced peak ground acceleration) (Hernandez et al., 2019; Tasalloti et al., 2021). However, it is essential to ensure that the ERGSI system has minimal leaching attributes and does not result in long-term negative impacts on the environment.