This thesis seeks to examine how the integration of play, small toys specifically, and the use of solution-focused brief therapy techniques can affect the outcomes for primary school aged children undergoing counselling. The setting is a counselling agency in Christchurch, New Zealand. A qualitative research approach is used and the data analysed using a narrative inquiry approach. The context of this study is the counselling service of an agency where young children, adolescents and their families are helped and supported through a variety of life issues. The counselling the participants are offered uses a combination of a solution-focused and play therapy where the purpose is to encourage clients to find exceptions to their presenting problems and identify their preferred future. The aim of this study is to help the children navigate their problem through a better understanding of and the gaining of personal skills and strengths. Participants were invited to be part of this study through the agency waiting list. The four included presented with a variety of reasons for coming to counselling yet these proved similar to that which the agency has been routinely presented with in the aftermath of the Canterbury earthquakes from 2011 to present day. Each participant had the consent of their parents or caregivers to engage in this project. The participants themselves separately agreed to engage in a solution- focused counselling process where the counsellor also integrated the use of small toys as part of the course. Counselling sessions were audiotaped, aspects photographed and analysed with a specific focus on client engagement. Four key themes emerged as the participants explored their personal narrative. Firstly, the “I’m OK” theme depicted in their first scaling activity, secondly a recognition that things could indeed be better and they needed help. Thirdly, a realisation of their own strengths and skills and finally that the future was an optimistic place to look forward to. These themes are described and explained through descriptions of the participant’s stories as well as self-reflection by the researcher. Transcriptions of sessions are included as are excerpts from the research journal and photographs of the use of the small toys by the children.
Voluntary turnover has been the subject of scholarly inquiry for more than 100 years and much is understood about the drivers of turnover, and the decision-making processes involved. To date most models of voluntary turnover have assumed a rational and sequential decision process, initiated primarily by dissatisfaction with the job and the perceived availability of alternatives. Operating within a strong predictive research agenda, countless studies have sought to validate, extend and refine these traditional models through the addition of distal antecedents, mediators, moderators, and proximal antecedents of turnover. The net result of this research is a large body of empirical support for a somewhat modest relationship between job dissatisfaction, perceived alternatives, turnover intentions, job search behaviour and actual turnover. Far less scholarly attention has been directed at understanding shock-induced turnover that is not necessarily derived from dissatisfaction. Moreover, almost no consideration has been given to understanding how a significant and commonly experienced extra-organisational shock, such as natural disaster, might impact turnover decision making. Additionally, the dynamic and cumulative impacts of multiple shocks on turnover decision making have to date not been examined by turnover researchers. In addressing these gaps this thesis presents a leaver-centric theory of employee turnover decision making that is grounded in the post-disaster context. Data for the study were collected from in-depth interviews with 31 leavers in four large organisations in Christchurch, New Zealand; an area that experienced a major natural disaster in the form of the Canterbury earthquake sequence. This context provided a unique setting in which to study turnover as the primary shock was followed by a series of smaller shocks, resulting in a period of sustained disruption to the pre-shock status quo. Grounded theory methods are used to develop a typology of leaving which describes four distinct patterns of turnover decision making that follow a significant extra-organisational shock. The proposed typology not only addresses the heterogeneous and complex nature of turnover decision making, but also provides a more nuanced explanation of the turnover process explicating how the choice of decision path followed is influenced by four contextual factors which emerged from the data: (1) pre-shock motivational state; (2) decision difficulty; (3) experienced shock magnitude; and (4) the availability of resources. The research findings address several shortcomings in the extant literature on employee turnover, and offer practical recommendations for managers seeking to retain employees in a post-disaster setting.
From 2010, Canterbury, a province of Aotearoa New Zealand, experienced three major disaster events. This study considers the socio-ecological impacts on cross-sectoral suicide prevention agencies and their service users of the 2010 – 2016 Canterbury earthquake sequence, the 2019 Christchurch mosque attacks and the COVID-19 pandemic in Canterbury. This study found the prolonged stress caused by these events contributed to a rise in suicide risk factors including anxiety, fear, trauma, distress, alcohol misuse, relationship breakdown, childhood adversity, economic loss and deprivation. The prolonged negative comment by the media on wellbeing in Canterbury was also unhelpful and affected morale. The legacy of these impacts was a rise in referrals to mental health services that has not diminished. This adversity in the socio-ecological system also produced post-traumatic growth, allowing Cantabrians to acquire resilience and help-seeking abilities to support them psychologically through the COVID-19 pandemic. Supporting parental and teacher responses, intergenerational support and targeted public health campaigns, as well as Māori family-centred programmes, strengthened wellbeing. The rise in suicide risk led to the question of what services were required and being delivered in Canterbury and how to enable effective cross-sectoral suicide prevention in Canterbury, deemed essential in all international and national suicide prevention strategies. Components from both the World Health Organisation Suicide Prevention Framework (WHO, 2012; WHO 2021) and the Collective Impact model (Hanleybrown et al., 2012) were considered by participants. The effectiveness of dynamic leadership and the essential conditions of resourcing a supporting agency were found as were the importance of processes that supported equity, lived experience and the partnership of Māori and non-Māori stakeholders. Cross-sectoral suicide prevention was found to enhance the wellbeing of participants, hastening learning, supporting innovation and raising awareness across sectors which might lower stigma. Effective communication was essential in all areas of cross-sectoral suicide prevention and clear action plans enabled measurement of progress. Identified components were combined to create a Collective Impact Suicide Prevention framework that strengthens suicide prevention implementation and can be applied at a local, regional and national level. This study contributes to cross-sectoral suicide prevention planning by considering the socio- ecological, policy and practice mitigations required to lower suicide risk and to increase wellbeing and post-traumatic growth, post-disaster. This study also adds to the growing awareness of the contribution that social work can provide to suicide prevention and conceptualises an alternative governance framework and practice and policy suggestions to support effective cross-sectoral suicide prevention.
<strong>Sea level rise is one consequence of Earth’s changing climate. Century-long tide gauge records show that global-mean sea-level rise reached 11-16 cm during the twentieth century at a mean rate of 1.2 mm/y. Today, the average rate of global-mean sea-level rise is higher at 3-4 mm/y and is expected to increase in the future. This represents a hazard to low elevation coastal zones worldwide. Yet, before global sea level projections can be used to characterise future coastal flood hazard at a local scale, the effects of tectonics (and other processes) that drive vertical land motion (VLM) must be considered. VLM is defined as the vertical velocity (uplift or subsidence) of the solid surface with respect to the centre of Earth. In this study, new VLM maps are generated over coastal strips in New Zealand, using Sentinel-1 InSAR and GNSS data.</strong>In New Zealand, measuring VLM using InSAR on naturally vegetated or agricultural land is difficult due to signal decorrelation. Along the rural Bay of Plenty coastal strip, I use a persistent-scatterer approach to generate a VLM map from both east-looking ascending and west-looking descending Sentinel-1 data between 2015-2021. Using time-series data over the same time period from a dense network of 20 GNSS sensors, I tie InSAR-derived line-of-sight velocity to the 2014 ITRF reference frame. I test two different methods for measuring VLM and compare the results against GNSS vertical velocity along the Bay of Plenty coast. Best results are achieved by first removing the interpolated horizontal GNSS velocity field from each of the InSAR datasets, before averaging the two VLM estimates. Measured VLM is between -3 and 3 mm/y, with negative values (subsidence) occurring within the low-lying Rangitāiki Plain and Ōpōtiki valley, and uplift across the elevated region west of Matatā.This thesis integrates geomorphological, geological, and historical levelling VLM records with modern satellite datasets to assess VLM across timescales ranging from 10 to 100,000 years at Matatā. Uplift rate has been variable through time, with average uplift over the last 300,000 years of 1 mm/y, 4.5 mm/y since 1720 years, 2 mm/y between 1950-1978, and 10 mm/y between 2004-2011. Previous modelling has shown that the best fit to the 2004-2011 rapid uplift rates is an inflating magmatic source at ~10 km depth beneath Matatā. To reconcile all data, I present a VLM model that consists of short-lived periods (7 years) of rapid uplift (10 mm/y), separated by longer periods (30 years) of lower background uplift (3 mm/y). The episodic nature of VLM at Matatā likely reflects short-lived periods of magmatic intrusion. Episodic VLM characterised by large rates of uplift (10 mm/y) has been seen at Taupō volcano, and other volcanic centers globally. It has been 12 years since the end of the last intrusion episode; this modelling suggest one may expect to observe increased uplift rates at Matatā in the coming decades. Densely populated urban coastal strips are most at risk from the effects of relative sea-level rise. At the same time, anthropogenic activities associated with urbanization, such as groundwater withdrawal, and land reclamation can lead to local land subsidence (LLS), further exacerbating the risk to urban infrastructure. LLS refers to subsidence relative to nearby land area assumed to be stable. In this thesis, I create the first high-resolution (10 m) maps of LLS at six urban coastal strips in New Zealand, with a combined length of 285 km, using Sentinel-1 InSAR data between 2018-2021. This analysis reveals 89% of urban coastal strips are subsiding at rates of -0.5 mm/y or greater, and 11% is subsiding at higher rates of -3.0 mm/y or greater. On average, subsidence is -0.6 to -2.9 mm/y higher at the coastal strip, compared to inland areas occupied by GNSS stations. This analysis also documents highly-localised hotspots of LLS, with subsidence rates of up to -15 mm/y. In Christchurch, rapid and localised subsidence (-8 mm/y) is observed within coastal suburbs New Brighton and Southshore. In most cities, the highest subsidence rates occur on land reclaimed in the early-late twentieth century, and in areas built on Holocene sediment. Time-series analysis of LLS at sites of reclaimed land shows both linear and non-linear rates of deformation over time periods of up to 6-8 years. This thesis highlights the variable exposure to relative sea-level rise of New Zealand coastal strips, and demonstrates that in many cases current rates of VLM should be expected to continue for the next few decades.
This dissertation addresses several fundamental and applied aspects of ground motion selection for seismic response analyses. In particular, the following topics are addressed: the theory and application of ground motion selection for scenario earthquake ruptures; the consideration of causal parameter bounds in ground motion selection; ground motion selection in the near-fault region where directivity effect is significant; and methodologies for epistemic uncertainty consideration and propagation in the context of ground motion selection and seismic performance assessment. The paragraphs below outline each contribution in more detail. A scenario-based ground motion selection method is presented which considers the joint distribution of multiple intensity measure (IM) types based on the generalised conditional intensity measure (GCIM) methodology (Bradley, 2010b, 2012c). The ground motion selection algorithm is based on generating realisations of the considered IM distributions for a specific rupture scenario and then finding the prospective ground motions which best fit the realisations using an optimal amplitude scaling factor. In addition, using different rupture scenarios and site conditions, two important aspects of the GCIM methodology are scrutinised: (i) different weight vectors for the various IMs considered; and (ii) quantifying the importance of replicate selections for ensembles with different numbers of desired ground motions. As an application of the developed scenario-based ground motion selection method, ground motion ensembles are selected to represent several major earthquake scenarios in New Zealand that pose a significant seismic hazard, namely, Alpine, Hope and Porters Pass ruptures for Christchurch city; and Wellington, Ohariu, and Wairarapa ruptures for Wellington city. A rigorous basis is developed, and sensitivity analyses performed, for the consideration of bounds on causal parameters (e.g., magnitude, source-to-site distance, and site condition) for ground motion selection. The effect of causal parameter bound selection on both the number of available prospective ground motions from an initial empirical as-recorded database, and the statistical properties of IMs of selected ground motions are examined. It is also demonstrated that using causal parameter bounds is not a reliable approach to implicitly account for ground motion duration and cumulative effects when selection is based on only spectral acceleration (SA) ordinates. Specific causal parameter bounding criteria are recommended for general use as a ‘default’ bounding criterion with possible adjustments from the analyst based on problem-specific preferences. An approach is presented to consider the forward directivity effects in seismic hazard analysis, which does not separate the hazard calculations for pulse-like and non-pulse-like ground motions. Also, the ability of ground motion selection methods to appropriately select records containing forward directivity pulse motions in the near-fault region is examined. Particular attention is given to ground motion selection which is explicitly based on ground motion IMs, including SA, duration, and cumulative measures; rather than a focus on implicit parameters (i.e., distance, and pulse or non-pulse classifications) that are conventionally used to heuristically distinguish between the near-fault and far-field records. No ad hoc criteria, in terms of the number of directivity ground motions and their pulse periods, are enforced for selecting pulse-like records. Example applications are presented with different rupture characteristics, source-to-site geometry, and site conditions. It is advocated that the selection of ground motions in the near-fault region based on IM properties alone is preferred to that in which the proportion of pulse-like motions and their pulse periods are specified a priori as strict criteria for ground motion selection. Three methods are presented to propagate the effect of seismic hazard and ground motion selection epistemic uncertainties to seismic performance metrics. These methods differ in their level of rigor considered to propagate the epistemic uncertainty in the conditional distribution of IMs utilised in ground motion selection, selected ground motion ensembles, and the number of nonlinear response history analyses performed to obtain the distribution of engineering demand parameters. These methods are compared for an example site where it is observed that, for seismic demand levels below the collapse limit, epistemic uncertainty in ground motion selection is a smaller uncertainty contributor relative to the uncertainty in the seismic hazard itself. In contrast, uncertainty in ground motion selection process increases the uncertainty in the seismic demand hazard for near-collapse demand levels.
Following the Canterbury earthquake sequence of 2010-11, a large and contiguous tract of vacated ‘red zoned’ land lies alongside the lower Ōtākaro / Avon River and is known as the Avon-Ōtākaro Red Zone (AORZ). This is the second report in the Ecological Regeneration Options (ERO) project that addresses future land uses in the AORZ. The purpose of this report is to present results from an assessment of restoration opportunities conducted in April 2017. The objectives of the assessment were to identify potential benefits of ecological restoration activities across both land and water systems in the AORZ and characterise the key options for their implementation. The focus of this report is not to provide specific advice on the methods for achieving specific restoration endpoints per se. This will vary at different sites and scales with a large number of combinations possible. Rather, the emphasis is on providing an overview of the many restoration and regeneration options in their totality across the AORZ. An additional objective is to support their adequate assessment in the identification of optimum land uses and adaptive management practices for the AORZ. Participatory processes may play a useful role in assessment and stakeholder engagement by providing opportunities for social learning and the co-creation of new knowledge. We used a facilitated local knowledge based approach that generated a large quantity of reliable and site specific data in a short period of time. By inviting participation from a wide knowledge-holder network inclusivity is improved in comparison to small-group expert panel approaches. Similar approaches could be applied to other information gathering and assessment needs in the regeneration planning process. Findings from this study represent the most comprehensive set of concepts available to date to address the potential benefits of ecological regeneration in the AORZ. This is a core topic for planning to avoid missed opportunities and opportunity costs. The results identify a wide range of activities that may be applied to generate benefits for Christchurch and beyond, all involving aspects of a potential new ecology in the AORZ. These may be combined at a range of scales to create scenarios, quantify benefits, and explore the potential for synergies between different land use options. A particular challenge is acquiring the information needed within relatively short time frames. Early attention to gathering baseline data, addressing technical knowledge gaps, and developing conceptual frameworks to account for the many spatio-temporal aspects are all key activities that will assist in delivering the best outcomes. Methodologies by which these many facets can be pulled together in quantitative and comparative assessments are the focus of the final report in the ERO series.
Museums around the world are often affected by major catastrophes, and yet planning for these disasters is an often neglected aspect of museum practice. New Zealand is not immune from these events, as can be seen in the recent series of serious earthquakes in Christchurch in 2010 and 2011. This dissertation considers how prepared the New Zealand museum sector is to handle unexpected events that negatively affect its buildings, staff, operations and treasured collections. The central research question was: What is the overall state of emergency planning in the New Zealand museum sector? There was a significant gap in the literature, especially in the local context, as there has been only one other comparable study conducted in Britain, and nothing locally. This dissertation makes a valuable contribution to the field of museum studies by drawing on theory from relevant areas such as crises management literature and by conducting original empirical research on a topic which has received little attention hitherto. The research employed a number of methods, including a review of background secondary sources, a survey and interviews. After contextualising the study with a number of local examples, Ian online survey was then developed an which enabled precise understanding of the nature of current museum practices and policies around emergency planning. Following this I conducted several interviews with museum professionals from a variety of institutional backgrounds which explored their thoughts and feelings behind the existing practices within the industry. The findings of the research were significant and somewhat alarming: almost 40% of the museum and galleries in New Zealand do not have any emergency plan at all, and only 11% have what they considered ‘complete’ plans. The research revealed a clear picture of the current width and depth of planning, as well as practices around updating the plans and training related to them. Within the industry there is awareness that planning for emergencies is important, but museum staff typically lack the knowledge and guidance needed to conduct effective emergency planning. As a result of the analysis, several practical suggestions are presented aimed at improving emergency planning practices in New Zealand museums. However this study has implications for museum studies and for current museum practice everywhere, as many of the recommendations for resolving the current obstacles and problems are applicable anywhere in the world, suggesting that New Zealand museums could become leaders in this important area.
As cities evolve, change and grow, the need and desire for adaptable architecture becomes evident across the nation. Architecture needs to undertake techniques that are flexible in order to adapt and align with the development of future generations in New Zealand. The Education industry is a primary example of a sector which requires flexibility within both classroom architectural form and interior configuration. This is a resultant of the recently updated Ministry of Education requirements; which state that every new classroom built or renovated nationwide, must implement the MoE classroom design standards for Innovative Learning Environments. ILE teaching spaces are configured as an open plan interior, supporting flexibility in classroom arrangement and teaching techniques. ILE classrooms are capable of evolving and adapting as educational practices evolve and change, allowing schools to remain modern and future focused. As part of this movement to ILE, the Ministry of Education has also recently made an attempt to improve the quality of temporary classrooms. This has been done by looking into the initiation of a programme that utilizes relocatable classroom buildings. Relocatable classrooms have been selected for multiple reasons, primarily flexibility. Flexibility is key for a school environment as it allows the school to actively respond to fluctuating school rolls. It is anticipated that the programme will provide a faster delivery process with a standardised design that allows the classrooms to be relocated from one school to another with relative ease. Following the devastating February 2011 earthquake the Greater Christchurch Region, the Education sector is in the midst of the Canterbury Schools Rebuild Programme. As a repercussion of this natural disaster, the majority of Christchurch schools have redevelopment or rebuild projects in progress, with preliminary design phases already in action for a small group of select schools regarded as high priority. The primary funding for these projects are sourced from insurance money, implementing tight budget restrictions, affecting the architectural design, quality and speed of the construction and repair works. The available funding limits the affordable classroom options to basic teaching spaces that have been stripped back to simple architectural forms, dictating not only the re-design, but also how our future generations will learn. Thus causing the development of the new student-led learning ILE concept to become controlled by existing construction techniques and the Rebuild Programmes budget restrictions. This thesis focuses on the future proofing of New Zealand schools by providing an affordable and time efficient alternative option to the current static, traditional construction, an option that has the ability to cater to the unpredictable fluctuating school rolls across the nation. This has been done by developing a prefabricated system for standalone classroom blocks. These blocks have the ability to be relocated between different school sites, dynamically catering to the unpredictable school roll numbers experienced across New Zealand. This site flexibility is reflected with the interior flexibility in the classrooms, enhancing the internal teaching space composition and challenges the existing design standards set by the Ministry of Education for Innovative Learning Environments. This system is called “Flexi-Ed”. Flexibility has been a key driver for this thesis, as the prefabricated structure is have to be flexible in three ways; first in the sense of being easy to assemble and disassemble. Second by offering flexible interior learning environments and thirdly the joints of the structure are designed with the ability to be flexible in order to cope with seismic activity. These three principles will provide schools with long term flexibility, minimal on-site interruption and heighten the standard of ILE across the nation. I strive to provide schools with long term flexibility and minimal site interruption, whilst heightening the standard of Innovative Learning Environments across New Zealand.
Field surveys and experimental studies have shown that light steel or timber framed plasterboard partition walls are particularly vulnerable to earthquake damage prompting the overarching objective of this research, which is to further the development of low damage seismic systems for non-structural partition walls in order to facilitate their adoption by industry to assist with reducing the losses associated with the maintenance and repair cost of buildings across their design life. In particular, this study focused on the behaviour of steel-framed partition walls systems with novel detailing that aim to be “low-damage” designed according to common practice for walls used in commercial and institutional buildings in New Zealand. This objective was investigated by (1) investigating the performance of a flexible track system proposed by researchers and industry by experimental testing of full-scale specimens; (2) investigating the performance of the seismic gap partition wall systems proposed in a number of studies, further developed in this study with input from industry, by experimental testing of full-scale specimens; and (3) investigating the potential implications of using these systems compared with traditionally detailed partition wall systems within multi-storey buildings using the Performance Based Earthquake Engineering loss assessment methodology. Three full-scale testing frames were designed in order to replicate, under controlled laboratory conditions, the effects of seismic shaking on partition walls within multi-storey buildings by the application of quasi-static uni-directional cyclic loading imposing an inter-storey drift. The typical configuration for test specimens was selected to be a unique “y-shape”, including one angled return wall, with typical dimensions of approximately 2400 mm along the main wall and 600 mm along (approximately) the returns walls with a height of 2405 mm from floor to ceiling. The specimens were aligned within test frames at an oblique angle to the direction of loading in order to investigate bi- directional effects. Three wall specimens with flexible track detailing, two identical plane specimens and the third including a doorway, were tested. The detailing involved removing top track anchors within the proximity of wall intersections, thus allowing the tracks to ‘bow’ out at these locations. Although the top track anchors were specified to be removed the proximity of wall intersections, a construction error was made whereby a single top track slab to concrete anchor was left in at the three-way wall junction. Despite this error, the experimental testing was deemed worthwhile since such errors will also occur in practice and because the behaviour of the wall can be examined with this fixing in mind. The specimens also included an acoustic/fire sealant at the top lining to floor boundary. In addition to providing drift capacities, the force-displacement behaviour is also reported, the dissipated energy was computed, and the parameters of the Wayne-Stewart hysteretic model were fitted to the results. The specimen with the door opening behaved significantly different to the plane specimens: damage to the doorway specimen began as cracking of the wallboard propagating from the corners of the doorway following which the L- and Y- shaped junctions behaved independently, whereas damage to the plane specimens began as cracking of the wallboard at the top of the L-junction and wall system deformed as a single unit. The results suggest that bi-directional behaviour is important even if its impact cannot be directly quantified by the experiments conducted. Damage to sealant implies that the bond between plasterboard and sealant is important for its seismic performance. Careful quality control is advised as defects in the bond may significantly impact its ability to withstand seismic movement. Two specimens with seismic gap detailing were tested: a steel stud specimen and a timber stud specimen. Observed drift capacities were significantly greater than traditional plasterboard partition systems. Equations were used to predict the drift at which damage state 1 (DS1) and damage state 2 (DS2) would initiate. The equation used to estimate the drift at the onset of DS1 accurately predicted the onset of plaster cracking but overestimated the drift at which the gap filling material was damaged. The equation used to predict the onset of DS2 provided a lower bound for both specimens and also when used to predict results of previous experimental tests on seismic gap systems. The gap-filling material reduced the drift at the onset of DS1, however, it had a beneficial effect on the re-centring behaviour of the linings. Out-of-plane displacements and return wall configuration did not appear to significantly impact the onset of plaster cracking in the specimens. A loss assessment according to the PBEE methodology was conducted on four steel MRF case study buildings: (1) a 4-storey building designed for the Christchurch region, (2) a 4-storey building designed for the Wellington region, (3) a 12-storey building designed for the Christchurch region, and (4) a 12- storey building designed for the Wellington region. The fragility parameters for a traditional partition system, the flexible track partition system, and the seismic gap steel stud and timber stud partition systems were included within the loss assessment. The order (lowest to highest) of each system in terms of the expected annual losses of each building when incorporating the system was, (1) the seismic gap timber stud system, (2) the seismic gap steel stud system, (3) the traditional/baseline system, and (4) the flexible track system. For the seismic gap timber stud system, which incurred the greatest reduction in expected annual losses for each case study building, the reduction in expected annual losses in comparison to the losses found when using the traditional system ranged from a 5% to a 30% reduction. This reinforces the fact that while there is a benefit to the using low damage partition systems in each building the extent of reduction in expected annual losses is significantly dependent on the particular building design and its location. The flexible track specimens had larger repair costs at small hazard levels compared to the traditional system but smaller repair costs at larger hazard levels. However, the resulting expected annual losses for the flexible track system was higher than the traditional system which reinforces findings from past studies which observed that the greatest contribution to expected annual losses arises from low to moderate intensity shaking seismic events (low hazard levels).
The research is funded by Callaghan Innovation (grant number MAIN1901/PROP-69059-FELLOW-MAIN) and the Ministry of Transport New Zealand in partnership with Mainfreight Limited. Need – The freight industry is facing challenges related to climate change, including natural hazards and carbon emissions. These challenges impact the efficiency of freight networks, increase costs, and negatively affect delivery times. To address these challenges, freight logistics modelling should consider multiple variables, such as natural hazards, sustainability, and emission reduction strategies. Freight operations are complex, involving various factors that contribute to randomness, such as the volume of freight being transported, the location of customers, and truck routes. Conventional methods have limitations in simulating a large number of variables. Hence, there is a need to develop a method that can incorporate multiple variables and support freight sustainable development. Method - A minimal viable model (MVM) method was proposed to elicit tacit information from industrial clients for building a minimally sufficient simulation model at the early modelling stages. The discrete-event simulation (DES) method was applied using Arena® software to create simulation models for the Auckland and Christchurch corridor, including regional pick-up and delivery (PUD) models, Christchurch city delivery models, and linehaul models. Stochastic variables in freight operations such as consignment attributes, customer locations, and truck routes were incorporated in the simulation. The geographic information system (GIS) software ArcGIS Pro® was used to identify and analyse industrial data. The results obtained from the GIS software were applied to create DES models. Life cycle assessment (LCA) models were developed for both diesel and battery electric (BE) trucks to compare their life cycle greenhouse gas (GHG) emissions and total cost of ownership (TCO) and support GHG emissions reduction. The line-haul model also included natural hazards in several scenarios, and the simulation was used to forecast the stock level of Auckland and Christchurch depots in response to each corresponding scenario. Results – DES is a powerful technique that can be employed to simulate and evaluate freight operations that exhibit high levels of variability, such as regional pickup and delivery (PUD) and linehaul. Through DES, it becomes possible to analyse multiple factors within freight operations, including transportation modes, routes, scheduling, and processing times, thereby offering valuable insights into the performance, efficiency, and reliability of the system. In addition, GIS is a useful tool for analysing and visualizing spatial data in freight operations. This is exemplified by their ability to simulate the travelling salesman problem (TSP) and conduct cluster analysis. Consequently, the integration of GIS into DES modelling is essential for improving the accuracy and reliability of freight operations analysis. The outcomes of the simulation were utilised to evaluate the ecological impact of freight transport by performing emission calculations and generating low-carbon scenarios to identify approaches for reducing the carbon footprint. LCA models were developed based on simulation results. Results showed that battery-electric trucks (BE) produced more greenhouse gas (GHG) emissions in the cradle phase due to battery manufacturing but substantially less GHG emissions in the use phase because of New Zealand's mostly renewable energy sources. While the transition to BE could significantly reduce emissions, the financial aspect is not compelling, as the total cost of ownership (TCO) for the BE truck was about the same for ten years, despite a higher capital investment for the BE. Moreover, external incentives are necessary to justify a shift to BE trucks. By using simulation methods, the effectiveness of response plans for natural hazards can be evaluated, and the system's vulnerabilities can be identified and mitigated to minimize the risk of disruption. Simulation models can also be utilized to simulate adaptation plans to enhance the system's resilience to natural disasters. Novel contributions – The study employed a combination of DES and GIS methods to incorporate a large number of stochastic variables and driver’s decisions into freight logistics modelling. Various realistic operational scenarios were simulated, including customer clustering and PUD truck allocation. This showed that complex pickup and delivery routes with high daily variability can be represented using a model of roads and intersections. Geographic regions of high customer density, along with high daily variability could be represented by a two-tier architecture. The method could also identify delivery runs for a whole city, which has potential usefulness in market expansion to new territories. In addition, a model was developed to address carbon emissions and total cost of ownership of battery electric trucks. This showed that the transition was not straightforward because the economics were not compelling, and that policy interventions – a variety were suggested - could be necessary to encourage the transition to decarbonised freight transport. A model was developed to represent the effect of natural disasters – such as earthquake and climate change – on road travel and detour times in the line haul freight context for New Zealand. From this it was possible to predict the effects on stock levels for a variety of disruption scenarios (ferry interruption, road detours). Results indicated that some centres rather than others may face higher pressure and longer-term disturbance after the disaster subsided. Remedies including coastal shipping were modelled and shown to have the potential to limit the adverse effects. A philosophical contribution was the development of a methodology to adapt the agile method into the modelling process. This has the potential to improve the clarification of client objectives and the validity of the resulting model.
Eccentrically Braced Frames (EBFs) are a widely used seismic resisting structural steel system. Since their inception in the late 1970s, they have been a viable option with an available stiffness that is between simple braced systems and moment resisting systems. A similar concept, the linked column frame (LCF), uses shear links between two closely spaced columns. In both cases, the key component is the active link or the shear link, and this component is the objective of this study. The performance of high rise EBF buildings in the 2010 and 2011 Christchurch earthquakes was beyond that which was expected, especially considering the very high accelerations recorded. As the concrete high-rises were torn down, two EBF buildings remained standing and only required some structural repair. These events prompted a renewed interest in bolted shear links, as well as their performance. While some research into replaceable shear links had already been done (Mansour, 2011), the objectives of this study were to improve on the shear link itself, with the consideration that links built in the future are likely to be bolted. The main components of this study were to: 1. Reduce or eliminate the requirements for intermediate web stiffeners, as they were suspected of being detrimental to performance. Furthermore, any reduction in stiffening requirements is a direct fabrication cost saving. Links with low web aspect ratios were found to achieve exceptional ductilities when no stiffeners were included, prompting new design equations. 2. Ensure that the stresses in the ends of links are adequately transferred into the endplates without causing fractures. Although most of the experimental links had web doubler plates included, four had varied lengths of such doubler plates from 0.0 in. to 8.0 in. The link without any doubler plates performed to a similar level to its peers, and thus it is likely that links with quality end details may not need web doubler plates at all. 3. Evaluate the performance of a link with double sided stiffeners without the use of web welds, as opposed to conventional single sided, welded stiffeners. This link performed well, and web-weld-less double sided stiffeners may be an economical alternative to conventional stiffeners for deeper sections of links. 4. Evaluate the performance of a link with thin endplates that are made efficient with the use of gusset plates. This link performed to an acceptable level and provides evidence for a cost effective alternative to thick endplates, especially considering the high overstrength end moments in links, typically requiring 16-bolt connections. 5. Examine the potential use of an alternative EBF arrangement where the collector beam is over sized, and the link section is formed by cutting out parts of the beam's web. After running a series of finite element models each with a unique variation, a number of approximate design rules were derived such that future research could develop this idea further experimentally. 6. Ensure that during testing, the secondary elements (members that are not the shear link), do not yield and are not close to yielding. None of the instrumented elements experienced any unexpected yielding, however the concerns for high stresses in the collector beam panel zone during design were warranted. The use of an existing New Zealand design equation is recommended as an extra check for design codes worldwide. The above objectives were mainly conducted experimentally, except: the data set for item 1 was greatly expanded through the use of a calibrated numerical model which was then used in an extensive parametric study; item 5 was purely finite element based; and, a small parametric study was included for item 3 in an attempt to expand on the trends found there.
This thesis describes the management process of innovation through construction infrastructure projects. This research focuses on the innovation management process at the project level from four views. These are categorised into the separate yet related areas of: “innovation definition”, “Project time”, “project team motivation” and “Project temporary organisation”. A practical knowledge is developed for each of these research areas that enables project practitioners to make the best decision for the right type of innovation at the right phase of projects, through a capable project organisation. The research developed a holistic view on both innovation and the construction infrastructure project as two complex phenomena. An infrastructure project is a long-term capital investment, highly risky and an uncertain. Infrastructure projects can play a key role in innovation and performance improvement throughout the construction industry. The delivery of an infrastructure project is affected in most cases by critical issues of budget constraint, programme delays and safety Where the business climate is characterized by uncertainty, risk and a high level of technological change, construction infrastructure projects are unable to cope with the requirement to develop innovation. Innovation in infrastructure projects, as one of the key performance indicators (KPI) has been identified as a critical capability for performance improvement through the industry. However, in spite of the importance of infrastructure projects in improving innovation, there are a few research efforts that have developed a comprehensive view on the project context and its drivers and inhibitors for innovation in the construction industry. Two main reasons are given as the inhibitors through the process of comprehensive research on innovation management in construction. The first reason is the absence of an understanding of innovation itself. The second is a bias towards research at a firm and individual level, so a comprehensive assessment of project-related factors and their effects on innovation in infrastructure projects has not been undertaken. This study overcomes these issues by adopting as a case study approach of a successful infrastructure project. This research examines more than 500 construction innovations generated by a unique infrastructure alliance. SCIRT (Stronger Christchurch Infrastructure Rebuild Team) is a temporary alliancing organisation that was created to rebuild and recover the damaged infrastructure after the Christchurch 2011 earthquake. Researchers were given full access to the innovation project information and innovation systems under a contract with SCIRT Learning Legacy, provided the research with material which is critical for understanding innovations in large, complex alliancing infrastructure organisation. In this research, an innovation classification model was first constructed. Clear definitions have been developed for six types of construction innovation with a variety of level of novelties and benefits. The innovation classification model was applied on the SCIRT innovation database and the resultant trends and behaviours of different types of innovation are presented. The trends and behaviours through different types of SCIRT innovations developed a unique opportunity to research the projectrelated factors and their effect on the behaviour of different classified types of innovation throughout the project’s lifecycle. The result was the identification of specific characteristics of an infrastructure project that affect the innovation management process at the project level. These were categorised in four separate chapters. The first study presents the relationship between six classified types of innovation, the level of novelty and the benefit they come up with, by applying the innovation classification model on SCIRT innovation database. The second study focused on the innovation potential and limitations in different project lifecycle phases by using a logic relationship between the six classified types of innovation and the three classified phases of the SCIRT project. The third study result develops a holistic view of different elements of the SCIRT motivation system and results in a relationship between the maturity level of definition developed for innovation as one of the KPIs and a desire though the SCIRT innovation incentive system to motivate more important innovations throughout the project. The fourth study is about the role of the project’s temporary organisation that finally results in a multiple-view innovation model being developed for project organisation capability assessment in the construction industry. The result of this thesis provides practical and instrumental knowledge to be used by a project practitioner. Benefits of the current thesis could be categorized in four groups. The first group is the innovation classification model that provides a clear definition for six classified types of innovation with four levels of novelty and specifically defined outcomes and the relationship between the innovation types, novelty and benefit. The second is the ability that is provided for the project practitioner to make the best decision for the right type of innovation at the right phases of a project’s lifecycle. The third is an optimisation that is applied on the SCIRT innovation motivation system that enables the project practitioner to incentivize the right type of innovation with the right level of financial gain. This drives the project teams to develop a more important innovation instead of a simple problemsolving one. Finally, the last and probably more important benefit is the recommended multiple-view innovation model. This is a tool that could be used by a project practitioner in order to empower the project team to support innovation throughout the project.
This project was initiated by ENGEO Limited and KiwiRail Holdings Limited to assess the stability of Slovens Creek Viaduct (specifically its western abutment) and a 3km section of rail corridor between Slovens Creek Viaduct and Avoca on the Midland Line (MDL). Commonly known as the scenic TranzAlpine rail journey (through Arthurs Pass National Park) the MDL connects Greymouth to Christchurch via Rolleston, where the MDL meets the Main South Line into Christchurch. The project area is approximately 40km southeast of Arthurs Pass Township, in the eastern extension of the Castle Hill Basin which is part of the Waimakariri Catchment and Canterbury Foothills. The field area is underlain by Rakaia Terrane, which is part of the Torlesse Composite Terrane forming the basement rock unit for the field area. Cretaceous-Tertiary rocks of the Castle Hill Basin overlie the basement strata and record a transgression-regression sequence, as well as mid-Oligocene submarine volcanism. The stratigraphic sequence in the Castle Hill Basin, and its eastern extension to Avoca, comprises two formations of the Eyre group, the older Broken River Formation and the younger Iron Creek Formation. Deep marine Porter Group limestones, marls, and tuffs of Oligocene age succeed the Iron Creek Formation of the Eyre Group, and probably records the maximum of the transgression. The Enys Formation lies disconformably on the Porter Group and is overlain unconformably by Late Pleistocene glacifluvial and glacial deposits. The Tertiary strata in the Slovens-Avoca rail corridor are weak, and the clay-rich tuff derived from mid-Oligocene volcanism is particularly prone to slaking. Extensive mapping carried out for this project has identified that some 90 percent of the surface along the length of the Slovens-Avoca corridor has been subject to mass movement. The landslides of the Slovens-Avoca rail corridor are clearly younger than the Last Glaciation, and Slovens Creek has been downcutting, with associated faulting and uplift, to form the present day geomorphology of the rail corridor. Deep-seated landslides in the rail corridor extend to Slovens Creek, locally deflecting the stream course, and a generic ground failure model for the rail corridor has been developed. Exploratory geotechnical investigations, including core drilling, installation of an inclinometer and a piezometer, enabled the construction of a simple ground model and cross section for the Slovens Creek Viaduct western abutment. Limit-equilibrium and pseudo-static slope stability analyses using both circular and block critical slip surface search methods were applied to the ground model for the western abutment of Slovens Creek Viaduct. Piezometric and strength data obtained during laboratory testing of core material have been used to constrain the western abutment stability assessment for one representative section line (C-C’). Prior to pseudo-static sensitivity analyses peak ground acceleration (PGA) for various Ultimate Limit State (ULS) design return periods, defined by an equation given in NZS1170.5:2004, were calculated and have been used as a calibration technique to find and compare specific PGA values for pseudo-static analyses in the Slovens Creek Viaduct area. The main purpose has been to provide an indication of how railway infrastructure could be affected by seismic events of various return periods defined by ULS design standards for the area. Limit equilibrium circular slip surface search methods, both grid search and auto refine search, indicated the slope is stable with a FoS greater than 1.0 returned from each, although one particular surface returned the lowest FoS in each. This surface is in the lower portion of the slope, adjacent to Slovens Stream and northeast of the MDL. As expected, pseudo-static analyses returned a lower FoS overall when compared to limit equilibrium analyses. The PGA analyses suggest that partial ground failure at the Slovens Creek Viaduct western abutment could occur in a 1 in 25-year return period event within materials on the slower slope beyond the immediate rail corridor. A ULS (1 in 500-year) event in the Slovens Creek Viaduct area would likely produce a PGA of ~0.9g, and the effects on the western abutment and rail infrastructure would most likely be catastrophic. Observed ground conditions for the western abutment of the Slovens Creek Viaduct suggest there is no movement within the landslide at depth within the monitoring timeframe of this project (22 May 2015 – 4 August 2015). Slope stability monitoring is recommended to be continued in two parts: (1) the inclinometer in BH1 is to be monitored on a six monthly basis for one year following completion of this thesis, and then annually unless ground movements become evident; and (2) surface movement monitoring should be installed using a fixed datum on the stable eastern abutment. Long-term stability management strategies for the Slovens Creek Viaduct western abutment are dependent upon future observed changes and ongoing monitoring. Hazard and risk assessment using the KiwiRail Qualitative Risk Assessment Framework (QRA) is recommended, and if slope stability becomes problematic for operation of the Midland Line consideration should be given to deep slope drainage. In the event of a large magnitude or high PGA earthquake all monitoring should be reviewed.
In most design codes, infill walls are considered as non-structural elements and thus are typically neglected in the design process. The observations made after major earthquakes (Duzce 1999, L’Aquila 2009, Christchurch 2011) have shown that even though infill walls are considered to be non-structural elements, they interact with the structural system during seismic actions. In the case of heavy infill walls (i.e. clay brick infill walls), the whole behaviour of the structure may be affected by this interaction (i.e. local or global structural failures such as soft storey mechanism). In the case of light infill walls (i.e. non-structural drywalls), this may cause significant economical losses. To consider the interaction of the structural system with the ‘non-structural ’infill walls at design stage may not be a practical approach due to the complexity of the infill wall behaviour. Therefore, the purpose of the reported research is to develop innovative technological solutions and design recommendations for low damage non-structural wall systems for seismic actions by making use of alternative approaches. Light (steel/timber framed drywalls) and heavy (unreinforced clay brick) non-structural infill wall systems were studied by following an experimental/numerical research programme. Quasi-static reverse cyclic tests were carried out by utilizing a specially designed full scale reinforced concrete frame, which can be used as a re-usable bare frame. In this frame, two RC beams and two RC columns were connected by two un-bonded post tensioning bars, emulating a jointed ductile frame system (PRESSS technology). Due to the rocking behaviour at the beam-column joint interfaces, this frame was typically a low damage structural solution, with the post-tensioning guaranteeing a linear elastic behaviour. Therefore, this frame could be repeatedly used in all of the tests carried out by changing only the infill walls within this frame. Due to the linear elastic behaviour of this structural bare frame, it was possible to extract the exact behaviour of the infill walls from the global results. In other words, the only parameter that affected the global results was given by the infill walls. For the test specimens, the existing practice of construction (as built) for both light and heavy non-structural walls was implemented. In the light of the observations taken during these tests, modified low damage construction practices were proposed and tested. In total, seven tests were carried out: 1) Bare frame , in order to confirm its linear elastic behaviour. 2) As built steel framed drywall specimen FIF1-STFD (Light) 3) As built timber framed drywall specimen FIF2-TBFD (Light) 4) As built unreinforced clay brick infill wall specimen FIF3-UCBI (Heavy) 5) Low damage steel framed drywall specimen MIF1-STFD (Light) 6) Low damage timber framed drywall specimen MIF2-TBFD (Light) 7) Low damage unreinforced clay brick infill wall specimen MIF5-UCBI (Heavy) The tests of the as built practices showed that both drywalls and unreinforced clay brick infill walls have a low serviceability inter-storey drift limit (0.2-0.3%). Based on the observations, simple modifications and details were proposed for the low damage specimens. The details proved to be working effectively in lowering the damage and increasing the serviceability drift limits. For drywalls, the proposed low damage solutions do not introduce additional cost, material or labour and they are easily applicable in real buildings. For unreinforced clay brick infill walls, a light steel sub-frame system was suggested that divides the infill panel zone into smaller individual panels, which requires additional labour and some cost. However, both systems can be engineered for seismic actions and their behaviour can be controlled by implementing the proposed details. The performance of the developed details were also confirmed by the numerical case study analyses carried out using Ruaumoko 2D on a reinforced concrete building model designed according to the NZ codes/standards. The results have confirmed that the implementation of the proposed low damage solutions is expected to significantly reduce the non-structural infill wall damage throughout a building.
This paper reports on a service-learning public journalism project in which postgraduate journalism students explore ways to engage with and report on diverse communities. Media scholars have argued that news media, and local newspapers in particular, must re-engage with their communities. Likewise, journalism studies scholars have urged educators to give journalism students greater opportunities to reflect on their work by getting out among journalism’s critics, often consumers or citizens concerned about content and the preparation of future journalists. The challenge for journalism educators is to prepare students for working in partnership with communities while also developing their ability to operate reflectively and critically within the expectations of the news media industry and wider society. The aim of this project has been to help students find ways to both listen and lead in a community, and also reflect on the challenges and critiques of community journalism practices. The project began in 2013 with stories about residents’ recovery following the devastating 2011 Canterbury earthquakes, and aimed to create stories that could contribute to community connection and engagement, and thereby resilience and recovery. The idea was inspired by research about post-disaster renewal that indicated that communities with strong social capital and social networks were more resilient and recovered more quickly and strongly. The project’s longer-term aim has been to explore community journalism practices that give greater power to citizens and communities by prioritising listening and processes of engagement. Over several months, students network with a community group to identify subjects with whom they will co-create a story, and then complete a story on which they must seek the feedback of their subject. Community leaders have described the project as a key example of how to do things “with people not to people”, and an outstanding contribution to the community-led component of Canterbury’s recovery. Analysis of student reflections, which are a key part of each year’s project, reveals the process of engaging with communities has helped students to map community dynamics, think more critically about source relationships, editorial choices and objectivity norms, and to develop a perspective on the diverse ways they can go about their journalism in the future. Each year, students partner with different groups and organisations, addressing different themes each time the project runs. For 2016, the programme proposes to develop the project in a new way, by not just exploring a community’s stories but also exploring its media needs and it aims to work with Christchurch’s new migrant Filipino community to develop the groundwork for a community media and/or communication platform, which Filipino community leaders say is a pressing need. For this iteration, journalism students will be set further research tasks aimed at deepening their ‘public listening’: they will conduct a survey of community members’ media use and needs as well as qualitative research interviews. It is hoped that the data collected will strengthen students’ understanding of their own journalism practice, as well as form the basis for work on developing media tools for minority groups who are generally poorly represented in mainstream media. In 2015, the journalism programme surveyed its community partners and held follow-up interviews with 13 of 18 story subjects to elicit further feedback on its news content and thereby deepen understanding of different community viewpoints. The survey and interview data revealed the project affected story subjects in a number of positive and interesting ways. Subjects said they appreciated the way student reporters took their time to build relationships and understand the context of the community groups with which they were involved, and contrasted this with their experience of professional journalists who had held pre-conceived assumptions about stories and/or rushed into interviews. As a direct consequence of the students’ approach, participants said they better trusted the student journalists to portray them accurately and fairly. Most were also encouraged by the positive recognition stories brought and several said the engagement process had helped their personal development, all of which had spin-offs for their community efforts. The presentation night that wraps up each year’s project, where community groups, story subjects and students come together to network and share the final stories, was cited as a significant positive aspect of the project and a great opportunity for community partners to connect with others doing similar work. Community feedback will be sought in future projects to inform and improve successive iterations.
Deconstruction, at the end of the useful life of a building, produces a considerable amount of materials which must be disposed of, or be recycled / reused. At present, in New Zealand, most timber construction and demolition (C&D) material, particularly treated timber, is simply waste and is placed in landfills. For both technical and economic reasons (and despite the increasing cost of landfills), this position is unlikely to change in the next 10 – 15 years unless legislation dictates otherwise. Careful deconstruction, as opposed to demolition, can provide some timber materials which can be immediately re-used (eg. doors and windows), or further processed into other components (eg. beams or walls) or recycled (‘cascaded’) into other timber or composite products (e.g. fibre-board). This reusing / recycling of materials is being driven slowly in NZ by legislation, the ‘greening’ of the construction industry and public pressure. However, the recovery of useful material can be expensive and uneconomic (as opposed to land-filling). In NZ, there are few facilities which are able to sort and separate timber materials from other waste, although the soon-to-be commissioned Burwood Resource Recovery Park in Christchurch will attempt to deal with significant quantities of demolition waste from the recent earthquakes. The success (or otherwise) of this operation should provide good information as to how future C&D waste will be managed in NZ. In NZ, there are only a few, small scale facilities which are able to burn waste wood for energy recovery (e.g. timber mills), and none are known to be able to handle large quantities of treated timber. Such facilities, with constantly improving technology, are being commissioned in Europe (often with Government subsidies) and this indicates that similar bio-energy (co)generation will be established in NZ in the future. However, at present, the NZ Government provides little assistance to the bio-energy industry and the emergence worldwide of shale-gas reserves is likely to push the economic viability of bio-energy further into the future. The behaviour of timber materials placed in landfills is complex and poorly understood. Degrading timber in landfills has the potential to generate methane, a potent greenhouse gas, which can escape to the atmosphere and cancel out the significant benefits of carbon sequestration during tree growth. Improving security of landfills and more effective and efficient collection and utilisation of methane from landfills in NZ will significantly reduce the potential for leakage of methane to the atmosphere, acting as an offset to the continuing use of underground fossil fuels. Life cycle assessment (LCA), an increasingly important methodology for quantifying the environmental impacts of building materials (particularly energy, and global warming potential (GWP)), will soon be incorporated into the NZ Green Building Council Greenstar rating tools. Such LCA studies must provide a level playing field for all building materials and consider the whole life cycle. Whilst the end-of-life treatment of timber by LCA may establish a present-day base scenario, any analysis must also present a realistic end-of-life scenario for the future deconstruction of any 6 new building, as any building built today will be deconstructed many years in the future, when very different technologies will be available to deal with construction waste. At present, LCA practitioners in NZ and Australia place much value on a single research document on the degradation of timber in landfills (Ximenes et al., 2008). This leads to an end-of-life base scenario for timber which many in the industry consider to be an overestimation of the potential negative effects of methane generation. In Europe, the base scenario for wood disposal is cascading timber products and then burning for energy recovery, which normally significantly reduces any negative effects of the end-of-life for timber. LCA studies in NZ should always provide a sensitivity analysis for the end-of-life of timber and strongly and confidently argue that alternative future scenarios are realistic disposal options for buildings deconstructed in the future. Data-sets for environmental impacts (such as GWP) of building materials in NZ are limited and based on few research studies. The compilation of comprehensive data-sets with country-specific information for all building materials is considered a priority, preferably accounting for end-of-life options. The NZ timber industry should continue to ‘champion’ the environmental credentials of timber, over and above those of the other major building materials (concrete and steel). End-of-life should not be considered the ‘Achilles heel’ of the timber story.
The Lake Coleridge Rock Avalanche Deposits (LCRADs) are located on Ryton Station in the middle Rakaia Valley, approximately 80 km west of Christchurch. Torlesse Supergroup greywacke is the basement material and has been significantly influenced by both active tectonics and glaciation. Both glacial and post-glacial processes have produced large volumes of material which blanket the bedrock on slopes and in the valley floors. The LCRADs were part of a regional study of rock avalanches by WHITEHOUSE (1981, 1983) and WHITEHOUSE and GRIFFITHS (1983), and a single rock avalanche event was recognised with a weathering rind age of 120 years B.P. that was later modified to 150 ± 40 years B.P. The present study has refined details of both the age and the sequence of events at the site, by identifying three separate rock avalanche deposits (termed the LCRA1, LCRA2 and LCRA3 deposits), which are all sourced from near the summit of Carriage Drive. The LCRA1 deposit is lobate in shape and had an estimated original deposit volume of 12.5 x 10⁶ m³, although erosion by the Ryton River has reduced the present day debris volume to 5.1 x 10⁶ m³. An optically stimulated luminescence date taken from sandy loess immediately beneath the LCRA1 deposit provided a maximum age for the rock avalanche event of 9,720 ± 750 years B.P., which is believed to be realistic given that this is shortly after the retreat of Acheron 3 ice from this part of the valley. Emplacement of rock avalanche material into an ancestral Ryton riverbed created a natural dam with a ~17 M m³ lake upstream. The river is thought to have created a natural spillway over the dam structure at ~557 m (a.s.l), and to have existed for a number of years before any significant downcutting occurred. Although a triggering mechanism for the LCRA1 deposit was poorly constrained, it is thought that stress rebound after glacial ice removal may have initiated failure. Due to the event occurring c.10,000 years ago, there was a lack of definition for a possible earthquake trigger, though the possibility is obvious. The LCRA₂ event had an original deposit volume of 0.66 x 10⁶ m³, and was constrained to the low-lying area adjacent to the Ryton River that had been created by river erosion of the LCRA1 deposit. Further erosion by the Ryton River has reduced the deposit volume to 0.4 x 10⁶ m³. A radiocarbon date from a piece of mānuka found within the LCRA2 deposit provided an age of 668 ± 36 years B.P., and this is thought to reliably date the event. The LCRA2 event also dammed the Ryton River, and the preservation of dam-break outwash terraces downstream from the deposit provides clear evidence of rapid dam erosion and flooding after overtopping, and breaching by the Ryton River. Based on the mean annual flow of the Ryton River, the LCRA2 lake would have taken approximately two weeks to fill assuming that there were no preferred breach paths and the material was relatively impermeable. The LCRA2 event is thought to have been coseismic with a fault rupture along the western segment of the PPAFZ, which has been dated at 600 ± 100 years B.P. by SMITH (2003). The small LCRA3 event was not able to be dated, but it is believed to have failed shortly after the LCRA2 event and it may in fact be a lag deposit of the second rock avalanche event possibly triggered by an aftershock. The deposit is only visible at one locality within the cliffs that line the Ryton River, and its lack of geomorphic expression is attributed to it occurring closely after the LCRA2 event, while the Ryton River was still dammed from the second rock avalanche event. A wedge-block of some 35,000 m³ of source material for a future rock avalanche was identified at the summit of Carriage Drive. The dilation of the rock mass, combined with unfavourably oriented sub-vertical bedding in the Torlesse Supergroup bedrock, has allowed toppling-style failure on both of the main ridge lines around the source area for the LCRADs. In the event of a future rock avalanche occurring within the Ryton riverbed an emergency response plan has been developed to provide a staged response, especially in relation to the camping ground located at the mouth of the Ryton River. A long-term management plan has also been developed for mitigation measures for the Ryton riverbed and adjacent floodplain areas downstream of a future rock avalanche at the LCRAD site.
Deformational properties of soil, in terms of modulus and damping, exert a great influence on seismic response of soil sites. However, these properties for sands containing some portion of fines particles have not been systematically addressed. In addition, simultaneous modelling of the modulus and damping behaviour of soils during cyclic loading is desirable. This study presents an experimental and computational investigation into the deformational properties of sands containing fines content in the context of site response analysis. The experimental investigation is carried on sandy soils sourced from Christchurch, New Zealand using a dynamic triaxial apparatus while the computational aspect is based on the framework of total-stress one-dimensional (1D) cyclic behaviour of soil. The experimental investigation focused on a systematic study on the deformational behaviour of sand with different amounts of fines content (particle diameter ≤ 75µm) under drained conditions. The silty sands were prepared by mixing clean sand with three different percentages of fines content. A series of bender element tests at small-strain range and stress-controlled dynamic triaxial tests at medium to high-strain ranges were conducted on samples of clean sand and silty sand. This allowed measurements of linear and nonlinear deformational properties of the same specimen for a wide strain range. The testing program was designed to quantify the effects of void ratio and fines content on the low-strain stiffness of the silty sand as well as on the nonlinear stress-strain relationship and corresponding shear modulus and damping properties as a function of cyclic shear strains. Shear wave velocity, Vs, and maximum shear modulus, Gmax, of silty sand was shown to be significantly smaller than the respective values for clean sands measured at the same void ratio, e, or same relative density, Dr. However, the test results showed that the difference in the level of nonlinearity between clean sand and silty sands was small. For loose samples prepared at an identical relative density, the behaviour of clean sand was slightly less nonlinear as compared to sandy soils with higher fines content. This difference in the nonlinear behaviour of clean sand and sandy soils was negligible for dense soils. Furthermore, no systematic influence of fines content on the material damping curve was observed for sands with fines content FC = 0 to 30%. In order to normalize the effects of fines on moduli of sands, equivalent granular void ratio, e*, was employed. This was done through quantifying the participation of fines content in the force transfer chain of the sand matrix. As such, a unified framework for modelling of the variability of shear wave velocity, Vs, (or shear modulus, Gmax) with void ratio was achieved for clean sands and sands with fines, irrespective of their fines content. Furthermore, modelling of the cyclic stress-strain behaviour based on this experimental program was investigated. The modelling effort focused on developing a simple constitutive model which simultaneously models the soil modulus and damping relationships with shear strains observed in laboratory tests. The backbone curve of the cyclic model was adopted based on a modified version of Kondner and Zelasko (MKZ) hyperbolic function, with a curvature coefficient, a. In order to simulate the hysteretic cycles, the conventional Masing rules (Pyke 1979) were revised. The parameter n, in the Masing’s criteria was assumed to be a function of material damping, h, measured in the laboratory. As such the modulus and damping produced by the numerical model could match the stress-strain behaviour observed in the laboratory over the course of this study. It was shown that the Masing parameter n, is strain-dependent and generally takes values of n ≤ 2. The model was then verified through element test simulations under different cyclic loadings. It was shown that the model could accurately simulate the modulus and the damping simultaneously. The model was then incorporated within the OpenSees computational platform and was used to scrutinize the effects of damping on one-dimensional seismic site response analysis. For this purpose, several strong motion stations which recorded the Canterbury earthquake sequence were selected. The soil profiles were modelled as semi-infinite horizontally layered deposits overlying a uniform half-space subjected to vertically propagating shear waves. The advantages and limitations of the nonlinear model in terms of simulating soil nonlinearity and associated material damping were further scrutinized. It was shown that generally, the conventional Masing criteria unconservatively may underestimate some response parameters such as spectral accelerations. This was shown to be due to larger hysteretic damping modelled by using conventional Masing criteria. In addition, maximum shear strains within the soil profiles were also computed smaller in comparison to the values calculated by the proposed model. Further analyses were performed to study the simulation of backbone curve beyond the strain ranges addressed in the experimental phase of this study. A key issue that was identified was that relying only on the modulus reduction curves to simulate the stress-strain behaviour of soil may not capture the actual soil strength at larger strains. Hence, strength properties of the soil layer should also be incorporated to accurately simulate the backbone curve.
The nonlinear dynamic soil-foundation-structure interaction (SFSI) can signifi cantly affect the seismic response of buildings, causing additional deformation modes, damage and repair costs. Because of nonlinear foundation behaviour and interactions, the seismic demand on the superstructure may considerably change, and also permanent deformations at the foundation level may occur. Although SFSI effects may be benefi cial to the superstructure performance, any advantage would be of little structural value unless the phenomenon can be reliably controlled and exploited. Detrimental SFSI effects may also occur, including acceleration and displacement response ampli cation and differential settlements, which would be unconservative to neglect. The lack of proper understanding of the phenomenon and the limited available simpli ed tools accounting for SFSI have been major obstacles to the implementation of integrated design and assessment procedures into the everyday practice. In this study concepts, ideas and practical tools (inelastic spectra) for the seismic design and assessment of integrated foundation-superstructure systems are presented, with the aim to explicitly consider the impact of nonlinearities occurring at the soil-foundation interface on the building response within an integrated approach, where the foundation soil and superstructure are considered as part of an integrated system when evaluating the seismic response, working synergically for the achievement of a target global performance. A conceptual performance-based framework for the seismic design and assessment of integrated foundation-superstructure systems is developed. The framework is based on the use of peak and residual response parameters for both the superstructure and the foundation, which are then combined to produce the system performance matrix. Each performance matrix allows for worsening of the performance when different contributions are combined. An attempt is made to test the framework by using case histories from the 2011 Christchurch earthquake, which are previously shown to have been severely affected by nonlinear SFSI. The application highlights the framework sensitivity to the adopted performance limit states, which must be realistic for a reliable evaluation of the system performance. Constant ductility and constant strength inelastic spectra are generated for nonlinear SFSI systems (SDOF nonlinear superstructure and 3DOF foundation allowing for uplift and soil yielding), representing multistorey RC buildings with shallow rigid foundations supported by cohesive soils. Different ductilities/strengths, hysteretic rules (Bi-linear, Takeda and Flag-Shape), soil stiffness and strength and bearing capacity factors are considered. Footings and raft foundations are investigated, characterized respectively by constant (3 and 8) and typically large bearing capacity factors. It is confi rmed that when SFSI is considered, the superstructure yielding force needed to satisfy a target ductility for a new building changes, and that similarly, for an existing building, the ductility demand on a building of a given strength varies. The extent of change of seismic response with respect to xed-base (FB) conditions depends on the class of soils considered, and on the bearing capacity factor (SF). For SF equal to 3, the stiffer soils enhance the nonlinear rotational foundation behaviour and are associated with reduced settlement, while the softer ones are associated with increased settlement response but not signi ficant rotational behaviour. On average terms, for the simplifi ed models considered, SFSI is found to be bene cial to the superstructure performance in terms of acceleration and superstructure displacement demand, although exceptions are recorded due to ground motion variability. Conversely, in terms of total displacement, a signi cant response increase is observed. The larger the bearing capacity factor, the more the SFSI response approaches the FB system. For raft foundation buildings, characterized by large bearing capacity factors, the impact of foundation response is mostly elastic, and the system on average approaches FB conditions. Well de fined displacement participation factors to the peak total lateral displacement are observed for the different contributions (i.e. peak foundation rotation and translation and superstructure displacement). While the superstructure and foundation rotation show compensating trends, the foundation translation contribution varies as a function of the moment-to-shear ratio, becoming negligible in the medium-to-long periods. The longer the superstructure FB period, the less the foundation response is signifi cant. The larger the excitation level and the less ductile the superstructure, the larger the foundation contribution to the total lateral displacement, and the less the superstructure contribution. In terms of hysteretic behaviour, its impact is larger when the superstructure response is more signifi cant, i.e. for the softer/weaker soils and larger ductilities. Particularly, for the Flag Shape rule, larger superstructure displacement participation factors and smaller foundation contributions are recorded. In terms of residual displacements, the total residual-to-maximum ratios are similar in amplitudes and trends to the corresponding FB system responses, with the foundation and superstructure contributions showing complementary trends. The impact of nonlinear SFSI is especially important for the Flag Shape hysteresis rule, which would not otherwise suffer of any permanent deformations. By using the generated peak and residual inelastic spectra (i.e. inelastic acceleration/ displacement modifi cation factor spectra, and/or participation factor and residual spectra), conceptual simplifi ed procedures for the seismic design and assessment of integrated foundation-superstructure systems are presented. The residual displacements at both the superstructure and foundation levels are explicitly considered. Both the force- and displacement-based approaches are explored. The procedures are de fined to be complementary to the previously proposed integrated performance-based framework. The use of participation factor spectra allows the designer to easily visualize the response of the system components, and could assist the decision making process of both the design and assessment of SFSI systems. The presented numerical results have been obtained using simpli ed models, assuming rigid foundation behaviour and neglecting P-Delta effects. The consideration of more complex systems including asymmetry in stiffness, mass, axial load and ground conditions with a exible foundation layout would highlight detrimental SFSI effects as related to induced differential settlements, while accounting for PDelta effects would further amplify the displacement response. Also, the adopted acceleration records were selected and scaled to match conventional design spectra, thus not representing any response ampli cation in the medium-to-long period range which could as well cause detrimental SFSI effects. While these limitations should be the subject of further research, this study makes a step forward to the understanding of SFSI phenomenon and its incorporation into performance-based design/assessment considerations.
