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Research papers, University of Canterbury Library

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

Research papers, University of Canterbury Library

Following the 2010-2011 Canterbury (New Zealand) earthquake sequence, lightly reinforced wall structures in the Christchurch central business district were observed to form undesirable crack patterns in the plastic hinge region, while yield penetration either side of cracks and into development zones was less than predicted using empirical expressions. To some extent this structural behaviour was unexpected and has therefore demonstrated that there may be less confidence in the seismic performance of conventionally designed reinforced concrete (RC) structures than previously anticipated. This paper provides an observation-based comparison between the behaviour of RC structural components in laboratory testing and the unexpected structural behaviour of some case study buildings in Christchurch that formed concentrated inelastic deformations. The unexpected behaviour and poor overall seismic performance of ‘real’ buildings (compared to the behaviour of laboratory test specimens) was due to the localization of peak inelastic strains, which in some cases has arguably led to: (i) significantly less ductility capacity; (ii) less hysteretic energy dissipation; and (iii) the fracture of the longitudinal reinforcement. These observations have raised concerns about whether lightly reinforced wall structures can satisfy the performance objective of “Life Safety” at the Ultimate Limit State. The significance of these issues and potential consequences has prompted a review of potential problems with the testing conditions and procedures that are commonly used in seismic experimentations on RC structures. This paper attempts to revisit the principles of RC mechanics, in particular, the influence of loading history, concrete tensile strength, and the quantity of longitudinal reinforcement on the performance of real RC structures. Consideration of these issues in future research on the seismic performance of RC might improve the current confidence levels in newly designed conventional RC structures.

Research papers, University of Canterbury Library

The 2015 New Zealand strong-motion database provides a wealth of new strong motion data for engineering applications. An important component of this database is the compilation of new site metadata, describing the soil conditions and site response at GeoNet strong motion stations. We have assessed and compiled four key site parameters for the ~460 GeoNet stations that recorded significant historical ground motions. Parameters include: site classification (NZS1170.5), Vs30, fundamental site period (Tsite) and depth to bedrock (Z1.0, i.e. depth to material with Vs > 1000 m/s). In addition, we have assigned a quality estimate (Quality 1 – 3) to these parameters to provide a qualitative estimate of the uncertainty. New highquality Tsite estimates have largely been obtained from newly available HVSR amplification curves and spectral ratios from inversion of regional strong motion data that has been reconciled with available geological information. Good quality Vs30 estimates, typically in urban centres, have also been incorporated following recent studies. Where site-specific measurements of Vs30 are not available, Vs30 is estimated based on surface geology following national Vs30 maps. New Z1.0 values have been provided from 3D subsurface models for Canterbury and Wellington. This database will be used in efforts to guide development and testing of new and existing ground motion prediction models in New Zealand. In particular, it will allow reexamination of the most important site parameters that control and predict site response in a New Zealand setting. Furthermore, it can be used to provide information about suitable rock reference sites for seismological research, and as a guide to site-specific references in the literature. We discuss compilation of the database, preliminary insights so far, and future directions.

Research papers, Victoria University of Wellington

Diverse Density proposes an alternative housing strategy to the idealistic top-down process of housing development.  The term ‘Top – down’ refers to a situation in which decisions are made by a few people in authority rather than by the people who are affected by the decisions (Cambridge).  Problems/Position/Question: New Zealand’s urban housing is in a period of flux. Pressures of densification have permitted the intervention of medium density housing development schemes but these are not always successful. These typically top-down processes often result in internally focused design schemes that do not adhere to their specific context. The subsequent design outcomes can cause detrimental impacts to the local, urban and architectural conditions.  With vast quantities of council regulations, building restrictions and design guidelines clouding over the housing sector, commonly referred to as ‘red tape’, occupant participation in the housing development sector is dwindling. A boundless separation between top-down and traditional housing processes has occurred and our existing neighbourhoods and historic architectural character are taking on the brunt of the problem. The thought-provoking, alternative housings strategies of key research theorists Alejandro Aravena and John Habraken frame positions that challenge contemporary densification methods with an alternative strategy.  This position is addressed by endeavoring to answer; How can demands for denser housing achieve dynamic design responses that adhere to changes in occupancy, function and local site conditions?  Aim: The aim of this thesis is to challenge New Zealand’s current housing densification methods by proposing an alternative densification strategy. Explicit devotion will be attributed to opposing top-down building developments. Secondly, this thesis aims to test a speculative site-specific housing model. The implementation of a Christchurch housing scenario will situate an investigative study to test the strategy and its ability to stimulate greater diversity, site responsiveness, functional adaptability and occupancy permutation. The post-earthquake housing conditions of Christchurch provide an appropriate scenario to test and implement design-led investigations.  Objectives: The primary objectives of this design-led research investigation it to challenge the idealistic top-down method of developing density with a new method to:  - Develop contextual architectural cohesion - Encourage residential diversity - Reinvigorate architectural autonomy - Respond to, and recognise, existing site conditions - Develop a housing model that: - Adapts to occupant functionality preferences - Caters to occupancy diversity - Achieves contextual responsiveness  The proposition is addressed through a speculative design-led scenario study. A well-established Christchurch urban environment is adopted to implement and critique the envisioned alternative strategy. Development of the designs responsiveness, adaptability, and functionality produce a prototype housing model that actively adheres to its particular context.  Implication: The implications of this research would be an alternative densification strategy to perceive the advancement of punctual assessment of building compliance. With accelerated building processes, the research may have implications for addressing New Zealand’s housing crisis whilst simultaneously providing diverse, personable and responsive architectural solutions. A more dynamic, up-to-date and responsive housing development sector would be informed.

Research papers, University of Canterbury Library

Access to clean and safe drinking water is a fundamental human requirement. However, in many areas of the world natural water sources have been impacted by a variety of biological and chemical contaminants. The ingestion of these contaminants may cause acute or chronic health problems. To prevent such illnesses, many technologies have been developed to treat, disinfect and supply safe drinking water quality. However, despite these advancements, water supply distribution systems can adversely affect the drinking water quality before it is delivered to consumers. The primary aim of this research was to investigate the effect that water distribution systems may have on household drinking water quality in Christchurch, New Zealand and Addis Ababa, Ethiopia. Water samples were collected from the source water and household taps in both cities. The samples were then tested for various physical, chemical and biological water quality parameters. The data collected was also used to determine if water samples complied with national drinking water quality standards in both countries. Independent samples t-test statistical analyses were also performed to determine if water quality measured in the samples collected from the source and household taps was significantly different. Water quality did not vary considerably between the source and tap water samples collected in Christchurch City. No bacteria were detected in any sample. However, the pH and total iron concentrations measured in source and tap water samples were found to be significantly different. The lower pH values measured in tap water samples suggests that corrosion may be taking place in the distribution system. No water samples transgressed the Drinking Water Standards for New Zealand (DWSNZ) MAVs. Monitoring data collected by the Christchurch City Council (CCC) was also used for comparison. A number of pH, turbidity and total iron concentration measurements collected by the CCC in 2011 were found to exceed the guideline values. This is likely due to structural damage to the source wells and pump-stations that occurred during the 2011 earthquake events. Overall, it was concluded that the distribution system does not adversely affect the quality of Christchurch City’s household drinking water. The water quality measured in samples collected from the source (LTP) and household taps in Addis Ababa was found to vary considerably. The water collected from the source complied with the Ethiopian (WHO) drinking water quality standards. However, tap water samples were often found to have degraded water quality for the physical and chemical parameters tested. This was especially the case after supply interruption and reinstatement events. Bacteria were also often detected in household tap water samples. The results from this study indicate that water supply disruptions may result in degraded water quality. This may be due to a drop in pipeline pressure and the intrusion of contaminants through the leaky and cross-connected pipes in the distribution network. This adversely affects the drinking water quality in Addis Ababa.

Research papers, University of Canterbury Library

Natural hazard disasters often have large area-wide impacts, which can cause adverse stress-related mental health outcomes in exposed populations. As a result, increased treatment-seeking may be observed, which puts a strain on the limited public health care resources particularly in the aftermath of a disaster. It is therefore important for public health care planners to know whom to target, but also where and when to initiate intervention programs that promote emotional wellbeing and prevent the development of mental disorders after catastrophic events. A large body of literature assesses factors that predict and mitigate disaster-related mental disorders at various time periods, but the spatial component has rarely been investigated in disaster mental health research. This thesis uses spatial and spatio-temporal analysis techniques to examine when and where higher and lower than expected mood and anxiety symptom treatments occurred in the severely affected Christchurch urban area (New Zealand) after the 2010/11 Canterbury earthquakes. High-risk groups are identified and a possible relationship between exposure to the earthquakes and their physical impacts and mood and anxiety symptom treatments is assessed. The main research aim is to test the hypothesis that more severely affected Christchurch residents were more likely to show mood and anxiety symptoms when seeking treatment than less affected ones, in essence, testing for a dose-response relationship. The data consisted of mood and anxiety symptom treatment information from the New Zealand Ministry of Health’s administrative databases and demographic information from the National Health Index (NHI) register, when combined built a unique and rich source for identifying publically funded stress-related treatments for mood and anxiety symptoms in almost the whole population of the study area. The Christchurch urban area within the Christchurch City Council (CCC) boundary was the area of interest in which spatial variations in these treatments were assessed. Spatial and spatio-temporal analyses were done by applying retrospective space-time and spatial variation in temporal trends analysis using SaTScan™ software, and Bayesian hierarchical modelling techniques for disease mapping using WinBUGS software. The thesis identified an overall earthquake-exposure effect on mood and anxiety symptom treatments among Christchurch residents in the context of the earthquakes as they experienced stronger increases in the risk of being treated especially shortly after the catastrophic 2011 Christchurch earthquake compared to the rest of New Zealand. High-risk groups included females, elderly, children and those with a pre-existing mental illness with elderly and children especially at-risk in the context of the earthquakes. Looking at the spatio-temporal distribution of mood and anxiety symptom treatments in the Christchurch urban area, a high rates cluster ranging from the severely affected central city to the southeast was found post-disaster. Analysing residential exposure to various earthquake impacts found that living in closer proximity to more affected areas was identified as a risk factor for mood and anxiety symptom treatments, which largely confirms a dose-response relationship between level of affectedness and mood and anxiety symptom treatments. However, little changes in the spatial distribution of mood and anxiety symptom treatments occurred in the Christchurch urban area over time indicating that these results may have been biased by pre-existing spatial disparities. Additionally, the post-disaster mobility activity from severely affected eastern to the generally less affected western and northern parts of the city seemed to have played an important role as the strongest increases in treatment rates occurred in less affected northern areas of the city, whereas the severely affected eastern areas tended to show the lowest increases. An investigation into the different effects of mobility confirmed that within-city movers and temporary relocatees were generally more likely to receive care or treatment for mood or anxiety symptoms, but moving within the city was identified as a protective factor over time. In contrast, moving out of the city from minor, moderately or severely damaged plain areas of the city, which are generally less affluent than Port Hills areas, was identified as a risk factor in the second year post-disaster. Moreover, residents from less damaged plain areas of the city showed a decrease in the likelihood of receiving care or treatment for mood or anxiety symptoms compared to those from undamaged plain areas over time, which also contradicts a possible dose-response relationship. Finally, the effects of the social and physical environment, as well as community resilience on mood and anxiety symptom treatments among long-term stayers from Christchurch communities indicate an exacerbation of pre-existing mood and anxiety symptom treatment disparities in the city, whereas exposure to ‘felt’ earthquake intensities did not show a statistically significant effect. The findings of this thesis highlight the complex relationship between different levels of exposure to a severe natural disaster and adverse mental health outcomes in a severely affected region. It is one of the few studies that have access to area-wide health and impact information, are able to do a pre-disaster / post-disaster comparison and track their sample population to apply spatial and spatio-temporal analysis techniques for exposure assessment. Thus, this thesis enhances knowledge about the spatio-temporal distribution of adverse mental health outcomes in the context of a severe natural disaster and informs public health care planners, not only about high-risk groups, but also where and when to target health interventions. The results indicate that such programs should broadly target residents living in more affected areas as they are likely to face daily hardship by living in a disrupted environment and may have already been the most vulnerable ones before the disaster. Special attention should be focussed on women, elderly, children and people with pre-existing mental illnesses as they are most likely to receive care or treatment for stress-related mental health symptoms. Moreover, permanent relocatees from affected areas and temporarily relocatees shortly after the disaster may need special attention as they face additional stressors due to the relocation that may lead to the development of adverse mental health outcomes needing treatment.

Research papers, University of Canterbury Library

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

Images, UC QuakeStudies

Photograph captioned by BeckerFraserPhotos, "A sign on the fence of a red zoned property in Lower Styx Road. The sign reads, 'Browlee an (sic) Sutton R Clowns. Haven't got it right! $75 He rip off'. Many of the homeowners in this area believe that their homes should not be red zoned as the damage is much less than in other red zoned areas".

Images, UC QuakeStudies

A photograph of a block of damaged shops on the corner of Gloucester Street and Woodham Road. The top of the façade has crumbled. The bricks have fallen to the ground and taken the awnings with them. Wire fencing has been placed around the buildings as a cordon. Signs on the fences indicated that the T Bakery and Red Chilli are open.

Images, UC QuakeStudies

The Cranmer Court building, on the corner of Kilmore and Montreal Streets, after the 22 February 2011 earthquake. Large pieces of the building have collapsed, including the octagonal corner section that housed Plato Creative from March 2008 to November 2009. Masonry has fallen onto the footpath and road, and the site has been enclosed in a safety fence to keep people away. The whitewashed interior walls of one of the apartments can be seen.

Audio, Radio New Zealand

In quake-ravaged Christchurch businesses are tentatively restarting, and infrastructure is being restored, but there's ongoing uncertainty about job losses and how people will survive financially. Within six days of the February earthquake; the Government had introduced a subsidy scheme for businesses and their employees, as well as people who'd found themselves out of a job. Now there's growing disquiet about what will happen to thousands of Cantabrians when that support scheme finishes at the end of May.

Images, UC QuakeStudies

Two men carry backpacks and shopping bags along Tuam Street, stepping over emergency tape that lies across the road. Brick dust covers the street where fallen bricks have been cleared. The photographer comments, "Two members of our office carrying gear through the cordon. This was taken shortly after the 4th September earthquake. Police allowed us free access past the cordon and simply advised us to watch out for falling masonry. The access situation was much different after the February aftershock".

Articles, UC QuakeStudies

A PDF copy of a full page advertisement from the All Right? 'Compliments' campaign that appeared in The Press in December 2013. The advertisement contains unique tear-off tab compliments and reads, "Free compliments. Give one away today. A kind word can mean the world to someone - so cut these out and share the Canterbury love." The advertisement also includes the web address of the All Right? Facebook page.

Images, UC QuakeStudies

A damaged car sits on top of the rubble of the Bealey Pharmacy. The photographer comments, "Bealey Avenue is open to traffic, as are many of the side streets, and the damage to buildings along this street is quite impressive and perhaps just a small taste of the damage that lies beyond the cordon ... A new feature now also appears to be a large pile of rubble with a new looking red Holden placed on top. Weird".

Images, UC QuakeStudies

A photograph of a tape artist creating a tape art bubble for the mural. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A photograph of a tape artist in front of the mural. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A proposed design by John Raven for a new cathedral, tied to a cordon fence. Clarendon Tower can be seen in the background. The photographer comments, "Someone is asking for designs for a new Christchurch Cathedral after it was announced that the old historical building will not be repaired, to be put on the fences through which people can see the de-construction of the old one. This design looks a great one to me".

Audio, Radio New Zealand

In half an hour, the first passenger train since the devastating Kaikoura earthquake will depart Picton for Christchurch. The 7.8 earthquake that struck the region in 2016 ripped up much of the scenic Coastal Pacific railway - sweeping kilometres of tracks out to sea and buried beneath slips. The rebuild of the railway line has taken two years and the efforts of nearly 1700 workers. Todd Moyle is KiwiRail's acting chief executive. He talks to Susie Ferguson.

Images, UC QuakeStudies

A residential property in Bexley with an overgrown garden. A wheelbarrow has been abandoned in the garden, and the garage door is tagged with graffiti. Dried liquefaction silt still covers the ground. The photographer comments, "Today I took a drive around the residential area between Bexley and New Brighton. It was a stark reminder to be thankful for the situation we're in and perhaps not complain too much that our garden wall hasn't yet been rebuilt".

Images, UC QuakeStudies

A photograph of tape artists and their creations in front of the mural. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A photograph of a tape artwork on the mural. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A photograph of a tape artist mimicking the tape artwork behind him. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A photograph of some of the tape artworks created by St Mary's School students. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A photograph of tape artists creating tape art bubbles for the mural. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A photograph of a tape artist ripping down a section of the tape art mural. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.

Images, UC QuakeStudies

A photograph of Tape Art NZ's 'bubble maker' artwork. The photograph was taken at Street Talk, a Tape Art residency held from 6 - 9 March 2014. Street Talk was a collaborative project between All Right?, Healthy Christchurch and Tape Art NZ that had Christchurch communities create large tape art murals on the south wall of Community and Public Health.