This paper discusses the seismic performance of the standard RC office building in Christchurch that is given as a structural design example in NZS3101, the concrete structures seismic standard in New Zealand. Firstly the push-over analysis was carried out to evaluate the lateral load carrying capacity of the RC building and then to compare that carrying capacity with the Japanese standard law. The estimated figures showed that the carrying capacity of the New Zealand standard RC office building of NZS3101:2006 was about one third of Japanese demanded carrying capacity. Secondly, time history analysis of the multi-mass system was performed to estimate the maximum response story drift angle using recorded ground motions. Finally, a three-dimensional analysis was carried out to estimate the response of the building to the 22nd February, 2011 Canterbury earthquake. The following outcomes were obtained. 1) The fundamental period of the example RC building is more than twice that of Japanese simplified calculation, 2) The example building’s maximum storey drift angle reached 2.5% under the recorded ground motions. The main purpose of this work is to provide background information of seismic design practice for the reconstruction of Christchurch.
Validating dynamic responses of engineered systems subjected to simulated ground motions is essential in scrutinising the applicability of simulated ground motions for engineering demand analyses. This paper compares the responses of two 3D building models subjected to recorded and simulated ground motions scaled to the NZS1170.5 design response spectrum, in order to evaluate the applicability of simulated ground motions for use in conventional engineering practice in New Zealand. The buildings were designed according to the NZS1170.5 and physically constructed in Christchurch prior to the 2010-2011 Canterbury earthquakes. 40 recorded ground motions from the 22 February 2011 Christchurch earthquake, along with the simulated ground motions for this event from Razafindrakoto et al. (2018) are considered. The seismic responses of the structures are principally quantified via the peak floor acceleration and maximum inter-storey drift ratio. Overall, the results indicate a general agreement in seismic demands obtained using the recorded and simulated ensembles of ground motions and provide further evidence that simulated ground motions using state-of-the-art methods can be used in code-based structural performance assessments inplace of, or in combination with, ensembles of recorded ground motions.
The 2010-2011 Christchurch earthquakes generated damage in several Reinforced Concrete (RC) buildings, which had RC walls as the principal resistant element against earthquake demand. Despite the agreement between structural engineers and researchers in an overall successfully performance there was a lack of knowledge about the behaviour of the damaged structures, and even deeper about a repaired structure, which triggers arguments between different parties that remains up to these days. Then, it is necessary to understand the capacity of the buildings after the earthquake and see how simple repairs techniques improve the building performance. This study will assess the residual capacity of ductile slender RC walls according to current standards in New Zealand, NZS 3101.1 2006 A3. First, a Repaired RC walls Database is created trying to gather previous studies and to evaluate them with existing international guidelines. Then, an archetype building is designed, and the wall is extracted and scaled. Four half-scale walls were designed and will be constructed and tested at the Structures Testing Laboratory at The University of Auckland. The overall dimensions are 3 [m] height, 2 [m] length and 0.175 [m] thick. All four walls will be identical, with differences in the loading protocol and the presence or absence of a repair technique. Results are going to be useful to assess the residual capacity of a damaged wall compare to the original behaviour and also the repaired capacity of walls with simpler repair techniques. The expected behaviour is focussed on big changes in stiffness, more evident than in previously tested RC beams found in the literature.
One of the failure modes that got the attention of researchers in the 2011 February New Zealand earthquake was the collapse of a key supporting structural wall of Grand Chancellor Hotel in Christchurch which failed in a brittle manner. However, until now this failure mode has been still a bit of a mystery for the researchers in the field of structural engineering. Moreover, there is no method to identify, assess and design the walls prone to such failure mode. Following the recent break through regarding the mechanism of this failure mode based on experimental observations (out-of-plane shear failure), a numerical model that can capture this failure was developed using the FE software DIANA. A comprehensive numerical parametric study was conducted to identify the key parameters contributing to the development of out-of-plane shear failure in reinforced concrete (RC) walls. Based on the earthquake observations, experimental and numerical studies conducted by the authors of this paper, an analytical method to identify walls prone to out-of-plane shear failure that can be used in practice by engineers is proposed. The method is developed based on the key parameters affecting the seismic performance of RC walls prone to out-of-plane shear failure and can be used for both design and assessment purposes
This paper presents preliminary results of an experimental campaign on three beam-column joint subassemblies extracted from a 22-storey reinforced concrete frame building constructed in late 1980s at the Christchurch’s Central Business District (CBD) area, damaged and demolished after the 2010-2011 Canterbury earthquakes sequence (CES). The building was designed following capacity design principles. Column sway (i.e., soft storey) mechanisms were avoided, and the beams were provided with plastic hinge relocation details at both beam-ends, aiming at developing plastic hinges away from the column faces. The specimens were tested under quasi-static cyclic displacement controlled lateral loading. One of the specimens, showing no visible residual cracks was cyclically tested in its as-is condition. The other two specimens which showed residual cracks varying between hairline and 1.0mm in width, were subjected to cyclic loading to simulate cracking patterns consistent with what can be considered moderate damage. The cracked specimens were then repaired with an epoxy injection technique and subsequently retested until reaching failure. The epoxy injection techniques demonstrated to be quite efficient in partly, although not fully, restoring the energy dissipation capacities of the damaged specimens at all beam rotation levels. The stiffness was partly restored within the elastic range and almost fully restored after the onset of nonlinear behaviour.
Paper 31 Structural members made of laminated veneer lumber (LVL) in combination with unbonded post-tensioning have recently been proposed, which makes it possible to design moment-resisting frames with longer spans for multi-storey timber buildings. It has been shown that prefabricated and prestressed timber structures can be designed to have excellent seismic resistance, with enhanced re-centring and energy dissipation characteristics. The post-tensioning provides re-centring capacity while energy is dissipated through yielding of mild steel dissipating devices. This paper summarizes an experimental investigation into the seismic response of LVL columns to bi-directional seismic loading, performed as part of a research programme on timber structures at the University of Canterbury. The experimental investigation includes testing under both quasi-static cyclic and pseudo-dynamic protocols. The results show excellent seismic performance, characterized by negligible damage of the structural members and small residual deformations, even under the combined effect of loading in two directions. Energy is dissipated mostly through yielding of external dissipators connecting the column and the foundation, which can be easily removed and replaced after an earthquake. Since post-tensioning can be economically performed on site, the system can be easily implemented in multi-storey timber buildings
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.
Welcome to the Recover newsletter Issue 5 from the Marine Ecology Research Group (MERG) of the University of Canterbury. Recover is designed to keep you updated on our MBIE-funded earthquake recovery project called RECOVER (Reef Ecology, Coastal Values & Earthquake Recovery). This 5th instalment covers the question of how much of the coast was uplifted and by how much, recent lab work on seaweed responses to stressors, and more on our drone survey work to quantify earthquake impacts and recovery along 130 km of coastline in the intertidal zone!
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.
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.
The capability of self-compacting concrete (SCC) in flowing through and filling in even the most congested areas makes it ideal for being used in congested reinforced concrete (RC) structural members such as beam-column joints (BCJ). However, members of tall multi-storey structures impose high capacity requirements where implementing normal-strength self-compacting concrete is not preferable. In the present study, a commercially reproducible high-strength self-compacting concrete (HSSCC), a conventionally vibrated high-strength concrete (CVHSC) and a normal strength conventionally vibrated concrete (CVC) were designed using locally available materials in Christchurch, New Zealand. Following the guidelines of the New Zealand concrete standards NZS3101, seven beam-column joints (BCJ) were designed. Factors such as the concrete type, grade of reinforcement, amount of joint shear stirrups, axial load, and direction of casting were considered variables. All BCJs were tested under a displacement-controlled quasi-static reversed cyclic regime. The cracking pattern at different load levels and the mode of failure were also recorded. In addition, the load, displacement, drift, ductility, joint shear deformations, and elongation of the plastic hinge zone were also measured during the experiment. It was found that not only none of the seismically important features were compromised by using HSSCC, but also the quality of material and ease of construction boosted the performance of the BCJs.
In this paper we introduce CityViewAR, a mobile outdoor Augmented Reality (AR) application for providing AR information visualization on a city scale. The CityViewAR application was developed to provide geographical information about the city of Christchurch, which was hit by several major earthquakes in 2010 and 2011. The application provides information about destroyed buildings and historical sites that were affected by the earthquakes. The geo-located content is provided in a number of formats including 2D map views, AR visualization of 3D models of buildings on-site, immersive panorama photographs, and list views. The paper describes the iterative design and implementation details of the application, and gives one of the first examples of a study comparing user response to AR and non-AR viewing in a mobile tourism application. Results show that making such information easily accessible to the public in a number of formats could help people to have richer experience about cities. We provide guidelines that will be useful for people developing mobile AR applications for city-scale tourism or outdoor guiding, and discuss how the underlying technology could be used for applications in other areas.
Rapid, accurate structural health monitoring (SHM) assesses damage to optimise decision-making. Many SHM methods are designed to track nonlinear stiffness changes as damage. However, highly nonlinear pinched hysteretic systems are problematic in SHM. Model-based SHM often fails as any mismatch between model and measured response dynamics leads to significant error. Thus, modelfree methods of hysteresis loop tracking methods have emerged. This study compares the robustness and accuracy in the presence of significant measurement noise of the proven hysteresis loop analysis (HLA) SHM method with 3 emerging model-free methods and 2 further novel adaptations of these methods using a highly nonlinear, 6-story numerical structure to provide a known ground-truth. Mean absolute errors in identifying a known nonlinear stiffness trajectory assessed at four points over two successive ground motion inputs from September 2010 and February 2011 in Christchurch range from 1.71-10.52%. However, the variability is far wider with maximum errors ranging from 3.90-49.72%, where the second largest maximum absolute error was still 19.74%. The lowest mean and maximum absolute errors were for the HLA method. The next best method had mean absolute error of 2.92% and a maximum of 10.51%. These results show the clear superiority of the HLA method over all current emerging model-free methods designed to manage the highly nonlinear pinching responses common in reinforced concrete structures. These results, combined with high robustness and accuracy in scaled and fullscale experimental studies, provide further validation for using HLA for practical implementation.
Prior to the devastating 2010 and 2011 earthquakes, parts of the CBD of Christchurch, New Zealand were undergoing revitalisation incorporating aspects of adaptive reuse and gentrification. Such areas were often characterised by a variety of bars, restaurants, and retail outlets of an “alternative” or “bohemian” style. These early 20th century buildings also exhibited relatively low rents and a somewhat chaotic and loosely planned property development approach by small scale developers. Almost all of these buildings were demolished following the earthquakes and a cordon placed around the CBD for several years. A paper presented at the ERES conference in 2013 presented preliminary results, from observation of post-earthquake public meetings and interviews with displaced CBD retailers. This paper highlighted a strongly held fear that the rebuild of the central city, then about to begin, would result in a very different style and cost structure from that which previously existed. As a result, permanent exclusion from the CBD of the types of businesses that previously characterised the successfully revitalised areas would occur. Five years further on, new CBD retail and office buildings have been constructed, but large areas of land between them remain vacant and the new buildings completed are often having difficulty attracting tenants. This paper reports on the further development of this long-term Christchurch case study and examines if the earlier predictions of the displaced retailers are coming true, in that a new CBD that largely mimics a suburban mall in style and tenancy mix, inherently loses some of its competitive advantage?
- 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.
The characteristics of the local environment such as access to community amenity and facilities and their impact on health and wellbeing have been well researched. The question is can local amenity confer similar benefits to help facilitate community resilience? Research following the Christchurch, New Zealand February 22nd 2011 earthquake has shown that socially connected communities were able to respond and adapt with collective action. The informal community response was important in supporting residents until infrastructure and more formal structures could be put in place. This research provides support to the importance of social connectedness prior to a disaster to help foster community resilience. It discusses the role of local infrastructure such as shops, local pubs and community amenity in providing gathering places for people to meet and interact and share information. It shows that geographically defined communities with central meeting places were able to use social connections and from this collective action as support. Resilience is a by-product of having good social connections and community amenity helps to facilitate those connections.
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.
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.
In 2010/11 Christchurch, New Zealand suffered a series of major earthquakes that resulted in significant damage to the physical and social environment. The majority of buildings suffered some type of damage, with an estimated 11% of homes requiring demolition. The total cost of rebuilding the city has been estimated at $31bn; equivalent to 17% of NZ’s annual GDP. The social impacts of the disaster are ongoing and difficult to estimate, with continuing social displacement throughout the city and metropolitan area. These impacts will continue to have a significant impact on community recovery and resilience for some time to come. This paper introduces the Greening the Greyfields research project, which aims to develop and implement of a number of tools to aid urban planning decision-making with an overt focus on community and stakeholder engagement in the post-disaster reconstruction of Christchurch. The research was initially developed in two Australian metropolitan areas (Perth and Melbourne) and has been extended to New Zealand, to help facilitate the reconstruction process in Christchurch. The project has developed a geospatial toolkit designed to help produce best reconstruction options, by identifying potential redevelopment precincts, and simulating different scenarios in a 3D visualisation environment. The implementation of the project in Christchurch includes direct feedback from different stakeholders, in order to get buy-in and make the reconstruction process more sustainable and community-inclusive. This paper will briefly outline the methodology comprising the tools, and how it encourages community and stakeholder involvement in the post-disaster reconstruction of Christchurch.
An overview of the 22 February 2011 Christchurch earthquake is presented in the context of characterization of extreme/rare events. Focus is given to the earthquake source, observed near-source strong ground motions, and effects of site response, while structural response and consequences are mentioned for completeness. For each of the above topics comparisons and discussions are made with predictive models for each of phenomena considered. In light of the observations and predictive model comparisons, the author’s opinion on improving the characterization of such extreme/rare events, and their appropriate consideration in seismic design is presented
This paper provides a brief discussion of observed strong ground motions from the 14 November 2016 Mw7.8 Kaikoura earthquake. Specific attention is given to examining observations in the near-source region where several ground motions exceeding 1.0g horizontal are recorded, as well as up to 2.7g in the vertical direction at one location. Ground motion response spectra in the near-source, North Canterbury, Marlborough and Wellington regions are also examined and compared with design levels. Observed spectral amplitudes are also compared with predictions from empirical and physics-based ground motion modelling.
Impact between structures of bridge sections can play a major, unexpected role in seismic structural damage. Linear and non-linear models are developed to analyze structural impact and response of two single-degree-of-freedom structures, representing adjacent buildings or bridge sections. The analyses presented assess probability of impact, displacement change due to impact, and the probability of increased displacement due to impact. These are assessed over a matrix of structural periods for each degree-of-freedom, different impact coefficients of restitution, and a probabilistically scaled suite of earthquake events. Linear versus non-linear effects are assessed using a Ramberg-Osgood non-linear model for column inelasticity. The normalized distance, or gap-ratio (GR), defined as a percentage of the summed spectral displacements, is used to create probabilistic design requirements. Increasing GR and structural periods that are similar (T2/T1~0.8-1.25) significantly decrease the likelihood of impact, and vice-versa. Including column inelasticity and decreasing coefficient of restitution decrease displacement increases due to impact and thus reduce potential damage. A minimum GR~0.5-0.9 ensures that any displacement increases will be less than 10% for 90% of ground motions over all structural period combinations (0.2-5.0sec). These results enable probabilistic design guidelines to manage undesirable effects of impact– an important factor during the recent Canterbury, New Zealand Earthquakes.
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.
Live monitoring data and simple dynamic reduced-order models of the Christchurch Women’s Hospital (CWH) help explain the performance of the base isolation (BI) system of the hospital during the series of Canterbury earthquakes in 2011-2012. A Park-Wen-Ang hysteresis model is employed to simulate the performance of the BI system and results are compared to measured data recorded above the isolation layer and on the 6th story. Simplified single, two and three degree of freedom models (SDOF, 2DOF and 3DOF) show that the CWH structure did not behave as an isolated but as a fixed-base structure. Comparisons of accelerations and deflections between simulated and monitored data show a good match for isolation stiffness values of approximately two times of the value documented in the design specification and test protocol. Furthermore, an analysis of purely measured data revealed very little to no relative motion across the isolators for large events of moment magnitude scale (Mw) 5.8 and 6.0 that occurred within 3 hours of each other on December 23, 2011. One of the major findings is that the BI system during the seismic events on December 23, 2011 did not yield and that the superstructure performed as a fixed-base building, indicating a need to reevaluate the analysis, design and implementation of these structures.
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.
This is an interim report from the research study performed within the NHRP Research Project “Impacts of soil liquefaction on land, buildings and buried pipe networks: geotechnical evaluation and design, Project 3: Seismic assessment and design of pipe networks in liquefiable soils”. The work presented herein is a continuation of the comprehensive study on the impacts of Christchurch earthquakes on the buried pipe networks presented in Cubrinovski et al. (2011). This report summarises the performance of Christchurch City’s potable water, waste water and road networks through the 2010-2011 Canterbury Earthquake Sequence (CES), and particularly focuses on the potable water network. It combines evidence based on comprehensive and well-documented data on the damage to the water network, detailed observations and interpretation of liquefaction-induced land damage, records and interpretations of ground motion characteristics induced by the Canterbury earthquakes, for a network analysis and pipeline performance evaluation using a GIS platform. The study addresses a range of issues relevant in the assessment of buried networks in areas affected by strong earthquakes and soil liquefaction. It discusses performance of different pipe materials (modern flexible pipelines and older brittle pipelines) including effects of pipe diameters, fittings and pipeline components/details, trench backfill characteristics, and severity of liquefaction. Detailed breakdown of key factors contributing to the damage to buried pipes is given with reference to the above and other relevant parameters. Particular attention is given to the interpretation, analysis and modelling of liquefaction effects on the damage and performance of the buried pipe networks. Clear link between liquefaction severity and damage rate for the pipeline has been observed with an increasing damage rate seen with increasing liquefaction severity. The approach taken here was to correlate the pipeline damage to LRI (Liquefaction Resistance Index, newly developed parameter in Cubrinovski et al., 2011) which represents a direct measure for the soil resistance to liquefaction while accounting for the seismic demand through PGA. Key quality of the adopted approach is that it provides a general methodology that in conjunction with conventional methods for liquefaction evaluation can be applied elsewhere in New Zealand and internationally. Preliminary correlations between pipeline damage (breaks km-1), liquefaction resistance (LRI) and seismic demand (PGA) have been developed for AC pipes, as an example. Such correlations can be directly used in the design and assessment of pipes in seismic areas both in liquefiable and non-liquefiable areas. Preliminary findings on the key factors for the damage to the potable water pipe network and established empirical correlations are presented including an overview of the damage to the waste water and road networks but with substantially less detail. A comprehensive summary of the damage data on the buried pipelines is given in a series of appendices.
“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.
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.
Background Up to 6 years after the 2011 Christchurch earthquakes, approximately one-third of parents in the Christchurch region reported difficulties managing the continuously high levels of distress their children were experiencing. In response, an app named Kākano was co-designed with parents to help them better support their children's mental health.Objective The objective of this study was to evaluate the acceptability, feasibility, and effectiveness of Kākano, a mobile parenting app to increase parental confidence in supporting children struggling with their mental health.Methods A cluster-randomized delayed access controlled trial was carried out in the Christchurch region between July 2019 and January 2020. Parents were recruited through schools and block randomized to receive immediate or delayed access to Kākano. Participants were given access to the Kākano app for 4 weeks and encouraged to use it weekly. Web-based pre- and postintervention measurements were undertaken.Results A total of 231 participants enrolled in the Kākano trial, with 205 (88.7%) participants completing baseline measures and being randomized (101 in the intervention group and 104 in the delayed access control group). Of these, 41 (20%) provided full outcome data, of which 19 (18.2%) were for delayed access and 21 (20.8%) were for the immediate Kākano intervention. Among those retained in the trial, there was a significant difference in the mean change between groups favoring Kākano in the brief parenting assessment (F<sub>1,39</sub>=7, P=.012) but not in the Short Warwick-Edinburgh Mental Well-being Scale (F<sub>1,39</sub>=2.9, P=.099), parenting self-efficacy (F<sub>1,39</sub>=0.1, P=.805), family cohesion (F<sub>1,39</sub>=0.4, P=.538), or parenting sense of confidence (F<sub>1,40</sub>=0.6, P=.457). Waitlisted participants who completed the app after the waitlist period showed similar trends for the outcome measures with significant changes in the brief assessment of parenting and the Short Warwick-Edinburgh Mental Well-being Scale. No relationship between the level of app usage and outcome was found. Although the app was designed with parents, the low rate of completion of the trial was disappointing.Conclusions Kākano is an app co-designed with parents to help manage their children's mental health. There was a high rate of attrition, as is often seen in digital health interventions. However, for those who did complete the intervention, there was some indication of improved parental well-being and self-assessed parenting. Preliminary indications from this trial show that Kākano has promising acceptability, feasibility, and effectiveness, but further investigation is warranted.Trial registration Australia New Zealand Clinical Trials Registry ACTRN12619001040156; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377824&isReview=true
Recent seismic events, such as the 2010-2011 Canterbury earthquakes and the 2016 Kaikōura earthquakes, have shed light on issues with the seismic performance of glazing systems. This is attributed to the limited amount of research and consideration of glazing systems in design and assessments. Previous research and evidence from post-earthquake reconnaissance have shown that glazing systems pose a hazard due to falling glass. As such, it is vital to ensure that glazing systems are designed with the necessary levels of seismic performance. Furthermore, the post-earthquake repair of glass facades can be costly and time-consuming. Some previous research has been conducted to highlight the seismic performance and fragility of glazing systems. However, most prior research only focussed on life-safety issues of glazing systems and rarely on the serviceability of glazing systems. The serviceability of glazing systems, such as water-tightness, is a vital aspect of glazing systems as a low serviceability capacity will increase the likelihood of further damage which will increase economic losses. This is the aim of this research, to provide insight towards the seismic performance of glazing systems considering both the serviceability and ultimate limit state by generating insight into the behaviour of glazing systems and developing tools for the consideration of glazing systems in design and assessment. This will allow a value proposition for seismic detailing of glazing to be evaluated. In order to provide insight into the behaviour of glazing systems and a means for evaluating their seismic performance, this research firstly develops an applicable experimental testing procedure that allows for serviceability limit state tests on glazing units. This experimental testing procedure is used to obtain data on the vulnerability of general New Zealand glazing systems’ performance, specifically unitised glazing systems that are commonly used as commercial shopfront glazing system types. These glazing systems typically realised using aluminium framing with gaskets connecting the frame to the glass. After the experimental testing, numerical analyses calibrated to the experimental testing results are conducted to enable robust analyses of glazing systems’ fragility. Finally, a value proposition for glazing systems with seismic detailing is made by comparing the performance of glazing systems with seismic detailing and conventional glazing systems. This comparison is done using the PEER-PBEE method and the economic implications of each glazing system is shown. Suggestions for designers and stakeholders aimed at reducing costs related to the seismic performance of glazing systems is also shown. Using the novel experimental method developed in this research, three different full-scale glazing systems were tested. A total of 10 unitised glazing specimens were tested; three with standard detailing, three with seismic detailing and four that were structurally glazed. These tests evaluated three damage states (DS): loss of water-tightness (DS1), gasket damage (DS2), and glass or framing failure (DS3). The experimental method that was adopted is considered to be more desirable than the optional procedures set out in New Zealand glazing standards. The method does not require high-speed testing equipment and is easy to replicate by the industry. The test results show that water-tightness was lost at low drift levels, with the first leakage occurring at just 0.15% drift for one specimen, while a standard glazing system had a median drift capacity of 0.35%. In contrast, seismic glazing systems detailed to better accommodate in-plane movements, demonstrated a significantly higher median drift capacity of 1.88%. The numerical approach proposed in this research has shown that it is possible to numerically model the glazing-gasket interaction to conservatively predict the water-leakage drift (damage state 1). The modelling approach still needs further development if it were to be used for damage states DS2 and DS3. The last part of the research considered the value proposition for seismic glazing systems. This was achieved by applying the FEMA P-58 performance assessment framework to a number of case study buldings that are typical of New Zealand design. The results suggest that it may not be economically worthwhile to use well-detailed seismic glazing systems despite the considerably larger drift capacity they possess relative to standard systems. However, as the cost of seismic glazing systems reduces, and more information on repair costs for different damage states is obtained, the value proposition may change.
