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Research papers, University of Canterbury Library

The collapse of Redcliffs’ cliff in the 22 February 2011 and 13 June 2011 earthquakes were the first times ever a major failure incident occurred at Redcliffs in approximately 6000 years. This master’s thesis is a multidisciplinary engineering geological investigation sought to study these particular failure incidents, focusing on collecting the data necessary to explain the cause and effect of the cliff collapsing in the event of two major earthquakes. This study provides quantitative and qualitative data about the geotechnical attributes and engineering geological nature of the sea-cut cliff located at Redcliffs. Results from surveying the geology of Redcliffs show that the exposed lithology of the cliff face is a variably jointed rock body of welded and (relatively intact) unwelded ignimbrite, a predominantly massive unit of brecciated tuff, and a covering of wind-blown loess and soil deposit (commonly found throughout Canterbury) on top of the cliff. Moreover, detailing the external component of the slope profile shows that Redcliffs’ cliff is a 40 – 80 m cliff with two intersecting (NE and SE facing) slope aspects. The (remotely) measured geometry of the cliff face comprises of multiple outstanding gradients, averaging a slope angle of ~67 degrees (post-13 June 2011), where the steepest components are ~80 degrees, whereas the gentle sloping sections are ~44 degrees. The physical structure of Redcliffs’ cliff drastically changed after each collapse, whereby seismically induced alterations to the slope geometry resulted in material deposited on the talus at the base of the cliff. Prior to the first collapse, the variance of the gradient down the slope was minimal, with the SE Face being the most variable with up to three major gradients on one cross section. However, after each major collapse, the variability increased with more parts of the cliff face having more than one major gradient that is steeper or gentler than the remainder of the slope. The estimated volume of material lost as a result of the gradient changes was 28,267 m³ in February and 11,360 m³ in June 2011. In addition, surveys of the cliff top after the failure incidents revealed the development of fissures along the cliff edge. Monitoring 10 fissures over three months indicated that fissured by the cliff edge respond to intense seismicity (generally ≥ Mw 4) by widening. Redcliffs’ cliff collapsed on two separate occasions as a result of an accumulated amount of damage of the rock masses in the cliff (caused by weathering and erosion over time), and two Mw 6.2 trigger earthquakes which shook the Redcliffs and the surrounding area at a Peak Ground Acceleration (PGA) estimated to be around 2 g. The results of the theoretical study suggests that PGA levels felt on-site during both instances of failure are the result of three major factors: source of the quake and the site affected; topographic amplification of the ground movement; the short distance between the source and the cliff for both fault ruptures; the focus of seismic energy in the direction of thrust faulting along a path that intercepts Redcliffs (and the Port Hills). Ultimately, failure on the NE and SE Faces of Redcliffs’ cliff was concluded to be global as every part of the exposed cliff face deposited a significant volume of material on the talus at the base of the cliff, with the exception of one section on the NE Face. The cliff collapses was a concurrent process that is a single (non-monotonic) event that operated as a complex series of (primarily) toppling rock falls, some sliding of blocks, and slumping of the soil mantle on top of the cliff. The first collapse had a mixture of equivalent continua slope movement of the heavily weathered / damaged surface of the cliff face, and discontinuous slope movement of the jointed inner slope (behind the heavily weathered surface); whereas the second collapse resulted in only discontinuous slope movement on account of the freshly exposed cliff face that had damage to the rock masses, in the form of old and (relatively) new discontinuous fractures, induced by earthquakes and aftershocks leading up to the point of failure.

Research papers, University of Canterbury Library

This dissertation addresses a diverse range of topics in the area of physics-based ground motion simulation with particular focus on the Canterbury, New Zealand region. The objectives achieved provide the means to perform hybrid broadband ground motion simulation and subsequently validates the simulation methodology employed. In particu- lar, the following topics are addressed: the development of a 3D seismic velocity model of the Canterbury region for broadband ground motion simulation; the development of a 3D geologic model of the interbedded Quaternary formations to provide insight on observed ground motions; and the investigation of systematic effects through ground motion sim- ulation of small-to-moderate magnitude earthquakes. The paragraphs below outline each contribution in more detail. As a means to perform hybrid broadband ground motion simulation, a 3D model of the geologic structure and associated seismic velocities in the Canterbury region is devel- oped utilising data from depth-converted seismic reflection lines, petroleum and water well logs, cone penetration tests, and implicitly guided by existing contour maps and geologic cross sections in data sparse subregions. The model explicitly characterises five significant and regionally recognisable geologic surfaces that mark the boundaries between geologic units with distinct lithology and age, including the Banks Peninsula volcanics, which are noted to strongly influence seismic wave propagation. The Basement surface represents the base of the Canterbury sedimentary basin, where a large impedance contrast exists re- sulting in basin-generated waves. Seismic velocities for the lithological units between the geologic surfaces are derived from well logs, seismic reflection surveys, root mean square stacking velocities, empirical correlations, and benchmarked against a regional crustal model, thus providing the necessary information for a Canterbury velocity model for use in broadband seismic wave propagation. A 3D high-resolution model of the Quaternary geologic stratigraphic sequence in the Canterbury region is also developed utilising datasets of 527 high-quality water well logs, and 377 near-surface cone penetration test records. The model, developed using geostatistical Kriging, represents the complex interbedded regional Quaternary geology by characterising the boundaries between significant interbedded geologic formations as 3D surfaces including explicit modelling of the formation unconformities resulting from the Banks Peninsula volcanics. The stratigraphic layering present can result in complex wave propagation. The most prevalent trend observed in the surfaces was the downward dip from inland to the eastern coastline as a result of the dominant fluvial depositional environment of the terrestrial gravel formations. The developed model provides a benefi- cial contribution towards developing a comprehensive understanding of recorded ground motions in the region and also providing the necessary information for future site char- acterisation and site response analyses. To highlight the practicality of the model, an example illustrating the role of the model in constraining surface wave analysis-based shear wave velocity profiling is illustrated along with the calculation of transfer functions to quantify the effect of the interbedded geology on wave propagation. Lastly, an investigation of systematic biases in the (Graves and Pitarka, 2010, 2015) ground motion simulation methodology and the specific inputs used for the Canterbury region is presented considering 144 small-to-moderate magnitude earthquakes. In the simulation of these earthquakes, the 3D Canterbury Velocity Model, developed as a part of this dissertation, is used for the low-frequency simulation, and a regional 1D velocity model for the high-frequency simulation. Representative results for individual earthquake sources are first presented to highlight the characteristics of the small-to-moderate mag- nitude earthquake simulations through waveforms, intensity measure scaling with source- to-site distance, and spectral bias of the individual events. Subsequently, a residual de- composition is performed to examine the between- and within-event residuals between observed data, and simulated and empirical predictions. By decomposing the residuals into between- and within-event residuals, the biases in source, path and site effects, and their causes, can be inferred. The residuals are comprehensively examined considering their aggregated characteristics, dependence on predictor variables, spatial distribution, and site-specific effects. The results of the simulation are also benchmarked against empir- ical ground motion models, where their similarities manifest from common components in their prediction. Ultimately, suggestions to improve the predictive capability of the simulations are presented as a result of the analysis.

Audio, Radio New Zealand

For over a decade, an irreplaceable ring laser has been trapped in a cavern 30m below Christchurch port hills. The Carl Zeiss laser was installed in an old World War Two bunker in 1997 until a rockfall after the 2011 Christchurch earthquake sealed the cavern. But now it's been rescued and is fully operational. Professor Jon-Paul Wells is the principal investigator on the ring laser project.

Videos, UC QuakeStudies

A video of Charlie Gates investigating the Christchurch City Council's plan to rejuvenate New Brighton mall. Gates interviews Sherry Dhamija, owner of Penguin House Dairy, Kate Thomas, manager of New Brighton Florist, and Colleen Biggs of Pegasus Tattoo about how business is going and what they think the area needs to be revitalised.

Research papers, University of Canterbury Library

Recent earthquakes have highlighted the vulnerability of existing structure to seismic loading. Current seismic retrofit strategies generally focus on increasing the strength/stiffness in order to upgrade the seismic performance of a structure or element. A typical drawback of this approach is that the demand on the structural and sub-structural elements can be increased. This is of particular importance when considering the foundation capacity, which may already be insufficient to allow the full capacity of the existing wall to develop (due to early codes being gravity load orientated). In this thesis a counter intuitive but rational seismic retrofit strategy, termed "selective weakening" is introduced and investigated. This is the first stage of an ongoing research project underway at the University of Canterbury which is focusing on developing selective weakening techniques for the seismic retrofit of reinforced concrete structures. In this initial stage the focus is on developing selective weakening for the seismic retrofit of structural walls. This is performed using a series of experimental, analytical and numerical investigations. A procedure for the assessment of existing structural walls is also compiled, based on the suggestions of currently available code provisions. A selective weakening intervention is performed within an overall performance-based retrofit approach with the aim of improving the inelastic behaviour by first reducing the strength/stiffness of specific members within the structural system. This will be performed with the intention of modifying a shear type behaviour towards a flexural type behaviour. As a result the demand on the structural member will be reduced. Once weakening has been implemented the designer can use the wide range of techniques and materials available (e.g. use of FRP, jacketing or shotcrete) to ensure that adequate characteristics are achieved. Whilst performing this it has to be assured that the structure meets specific performance criteria and the principles of capacity design. A target of the retrofit technique is the ability to introduce the characteristics of recently developed high performance seismic resisting systems, consisting of a self centring and dissipative behaviour (commonly referred to as a hybrid system). In this thesis, results of experimental investigations performed on benchmark and selectively weakened walls are discussed. The investigations consisted of quasi-static cyclic uni-directional tests on two benchmark and two retrofitted cantilever walls. The first benchmark wall is detailed as typical of pre-1970's construction practice. An equivalent wall is retrofitted using a selective weakening approach involving a horizontal cut at foundation level to allow for a rocking response. The second benchmark wall represents a more severe scenario where the inelastic behaviour is dominated by shear. A retrofit solution involving vertically segmenting the wall to improve the ductility and retain gravity carrying capacity by inducing a flexural response is implemented. Numerical investigations on a multi-storey wall system are performed using non linear time history analysis on SDOF and MDOF lumped plasticity models, representing an as built and retrofitted prototype structure. Calibration of the hysteretic response to experimental results is carried out (accounting for pinching and strength degradation). The sensitivity of maximum and residual drifts to p-delta and strength degradation is monitored, along with the sensitivity of the peak base shear to higher mode affects. The results of the experimental and analytical investigations confirmed the feasibility and viability of the proposed retrofit technique, towards improving the seismic performance of structural walls.

Research papers, University of Canterbury Library

Seismically vulnerable buildings constitute a major problem for the safety of human beings. In many parts of the world, reinforced concrete (RC) frame buildings designed and constructed with substandard detailing, no consideration of capacity design principles, and improper or no inclusion of the seismic actions, have been identified. Amongst those vulnerable building, one particular typology representative of the construction practice of the years previous to the 1970’s, that most likely represents the worst case scenario, has been widely investigated in the past. The deficiencies of that building typology are related to non-ductile detailing in beam column joints such as the use of plain round bars, the lack of stirrups inside the joint around the longitudinal reinforcement of the column, the use of 180° end hooks in the beams, the use of lap splices in potential ‘plastic hinge’ regions, and substandard quality of the materials. That type of detailing and the lack of a capacity design philosophy create a very fragile fuse in the structure where brittle inelastic behaviour is expected to occur, which is the panel zone region of exterior beam column joints. The non-ductile typology described above was extensively investigated at the University of Canterbury in the context of the project ‘Retrofit Solutions for New Zealand Multi-Storey Buildings’ (2004-2011), founded by the ‘Foundation for Research, Science and Technology’ Tūāpapa Rangahau Pūtaiao. The experimental campaign prior to the research carried out by the author consisted of quasi-static tests of beam column joint subassemblies subjected to lateral loading regime, with constant and varying axial load in the column. Most of those specimens were representative of a plane 2D frame (knee joint), while others represented a portion of a space 3D frame (corner joints), and only few of them had a floor slab, transverse beams, and lap splices. Using those experiments, several feasible, cost-effective, and non-invasive retrofit techniques were developed, improved, and refined. Nevertheless, the slow motion nature of those experiments did not take into account the dynamical component inherent to earthquake related problems. Amongst the set of techniques investigated, the use of FRP layers for strengthening beam column joints is of particular interest due to its versatility and the momentum that its use has gained in the current state of the practice. That particular retrofit technique was previously used to develop a strengthening scheme suitable for plane 2D and space 3D corner beam column joints, but lacking of floor slabs. In addition, a similar scheme was not developed for exterior joints of internal frames, referred here as ‘cruciform’. In this research a 2/5 scale RC frame model building comprising of two frames in parallel (external and internal) joined together by means of floor slabs and transverse beams, with non-ductile characteristics identical to those of the specimens investigated previously by others, and also including lap splices, was developed. In order to investigate the dynamic response of that building, a series of shake table tests with different ground motions were performed. After the first series of tests, the specimen was modified by connecting the spliced reinforcement in the columns in order to capture a different failure mode. Ground motions recorded during seismic events that occurred during the initial period of the experimental campaign (2010) were used in the subsequent experiments. The hierarchy of strengths and sequence of events in the panel zone region were evaluated in an extended version of the bending moment-axial load (M-N) performance domain developed by others. That extension was required due to the asymmetry in the beam cross section introduced by the floor slab. In addition, the effect of the torsion resistance provided by the spandrel (transverse beam) was included. In order to upgrade the brittle and unstable performance of the as-built/repaired specimen, a practical and suitable ad-hoc FRP retrofit intervention was developed, following a partial retrofit strategy that aimed to strengthen exterior beam column joints only (corner and cruciform). The ability of the new FRP scheme to revert the sequence of events in the panel zone region was evaluated using the extended version of the M-N performance domain as well as the guidelines for strengthening plane joints developed by others. Weakening of the floor slab in a novel configuration was also incorporated with the purpose of reducing the flexural capacity of the beam under negative bending moment (slab in tension), enabling the damage relocation from the joint into the beam. The efficacy of the developed retrofit intervention in upgrading the seismic performance of the as-built specimen was investigated using shake table tests with the input motions used in the experiments of the as-built/repaired specimen. Numerical work aimed to predict the response of the model building during the most relevant shake table tests was carried out. By using a simple numerical model with concentrated plasticity elements constructed in Ruaumoko2D, the results of blind and post-experimental predictions of the response of the specimen were addressed. Differences in the predicted response of the building using the nominal and the actual recorded motions of the shake table were investigated. The dependence of the accuracy of the numerical predictions on the assumed values of the parameters that control the hysteresis rules of key structural members was reviewed. During the execution of the experimental campaign part of this thesis, two major earthquakes affected the central part of Chile (27 of February 2010 Maule earthquake) and the Canterbury region in New Zealand (22 February 2011 Canterbury earthquake), respectively. As the author had the opportunity to experience those events and investigate their consequences in structures, the observations related to non-ductile detailing and drawbacks in the state of the practice related to reinforced concrete walls was also addressed in this research, resulting in preliminary recommendations for the refinement of current seismic code provisions and assessment guidelines. The investigations of the ground motions recorded during those and other earthquakes were used to review the procedures related to the input motions used for nonlinear dynamic analysis of buildings as required by most of the current code provisions. Inelastic displacement spectra were constructed using ground motions recorded during the earthquakes mentioned above, in order to investigate the adequacy of modification factors used to obtain reduced design spectra from elastic counterparts. Finally a simplified assessment procedure for RC walls that incorporates capacity compatible spectral demands is proposed.

Audio, Radio New Zealand

For many years the Heathcote-Avon estuary was the dumping ground for Christchurch's sewage. Then, in 2010, the wastewater was diverted well out to sea, via a long pipe. David Schiel from the University of Canterbury and John Zeldis from NIWA were investigating the effects of this diversion on the health of estuary when the 2011 Christchurch earthquakes happened, re-engineering both the estuary and their experiments.

Articles, UC QuakeStudies

This thesis was completed by Abigail Thompson for her Master of Architecture (Professional) at the University of Auckland in 2012. It was initiated with the aim of the addressing the destruction of many Christchurch buildings following the earthquakes, and investigates the role of architecture in public memory and ways of reconnecting people with the city. Note that some images in the thesis have been obscured in order to avoid copyright infringement.

Research papers, University of Canterbury Library

Beach ridge stratigraphy can provide an important record of both sustained coastal progradation and responses to events such as extreme storms, as well as evidence of earthquake induced sediment pulses. This study is a stratigraphic investigation of the late Holocene mixed sand gravel (MSG) beach ridge plain on the Canterbury coast, New Zealand. The subsurface was imaged along a 370 m shore-normal transect using 100 and 200 MHz ground penetrating radar (GPR) antennae, and cored to sample sediment textures. Results show that, seaward of a back-barrier lagoon, the Pegasus Bay beach ridge plain prograded almost uniformly, under conditions of relatively stable sea level. Nearshore sediment supply appears to have created a sustained sediment surplus, perhaps as a result of post-seismic sediment pulses, resulting in a flat, morphologically featureless beach ridge plain. Evidence of a high magnitude storm provides an exception, with an estimated event return period in excess of 100 years. Evidence from the GPR sequence combined with modern process observations from MSG beaches indicates that a paleo storm initially created a washover fan into the back-barrier lagoon, with a large amount of sediment simultaneously moved off the beach face into the nearshore. This erosion event resulted in a topographic depression still evident today. In the subsequent recovery period, sediment was reworked by swash onto the beach as a sequence of berm deposit laminations, creating an elevated beach ridge that also has a modern-day topographic signature. As sediment supply returned to normal, and under conditions of falling sea level, a beach ridge progradation sequence accumulated seaward of the storm feature out to the modern-day beach as a large flat, uniform progradation plain. This study highlights the importance of extreme storm events and earthquake pulses on MSG coastlines in triggering high volume beach ridge formation during the subsequent recovery period.

Research Papers, Lincoln University

The aftermath of three earthquakes has forced Christchurch to re-plan and rebuild. New perspectives of a sustainable city have arisen granting Christchurch the chance of becoming an example to the world. This work is centred on bioclimatic landscape design as a base for greening strategies. It deals with strategic landscape design adapted to a specific climate, from a user’s perspective. The investigation will be applied to Christchurch’s urban centres, assessing cultural adaptability to the local climate and implications for landscape design. Climatic data shows that humidity is not a local problem. However, the wind is the determinant. In Christchurch the solar radiation and the prevailing winds are the most important microclimatic variables, the latter intensifying the loss of surface heat, decreasing the radiant temperature and affecting thermal sensation. The research objective is to explore design parameters at the street-scale and identify ways to maximise thermal comfort in outdoor spaces through design-based strategies. The investigation will apply methods of participant observation, depth interviews, climatic data collection and design experimentation based on thermal comfort models and computer simulation tools. Case study sites chosen for investigation are places with current levels of activity that may be anticipated in the rebuild of the central city. The research will have two main outcomes: improved understanding of local urban culture adaptation to microclimate, and a demonstration of how design can enhance adaption. These outcomes will inform designers and city managers about good design practices and strategies that can be used to ensure a long term liveable city.

Research Papers, Lincoln University

The urban environment influences the way people live and shape their everyday lives, and microclimate sensitive design can enhance the use of urban streets and public spaces. Innovative approaches to urban microclimate design will become more important as the world’s population becomes ever more urban, and climate change generates more variability and extremes in urban microclimatic conditions. However, established methods of investigation based upon conventions drawn from building services research and framed by physiological concepts of thermal comfort may fail to capture the social dynamics of urban activity and their interrelationship with microclimate. This research investigates the relationship between microclimate and urban culture in Christchurch, New Zealand, based upon the concept of urban comfort. Urban comfort is defined as the socio-cultural (therefore collective) adaptation to microclimate due to satisfaction with the urban environment. It involves consideration of a combination of human thermal comfort requirements and adaptive comfort circumstances, preferences and strategies. A main methodological challenge was to investigate urban comfort in a city undergoing rapid physical change following a series of major earthquakes (2010-2011), and that also has a strongly seasonal climate which accentuates microclimatic variability. The field investigation had to be suitable for rapidly changing settings as buildings were demolished and rebuilt, and be able to capture data relevant to a cycle of seasons. These local circumstances meant that Christchurch was valuable as an example of a city facing rapid and unpredictable change. An interpretive, integrative, and adaptive research strategy that combined qualitative social science methods with biophysical measures was adopted. The results are based upon participant observation, 86 in-depth interviews with Christchurch residents, and microclimate data measurements. The interviews were carried out in a variety of urban settings including established urban settings (places sustaining relatively little damage) and emerging urban settings (those requiring rebuilding) during 2011-2013. Results of this research show that urban comfort depends on adaptive strategies which in turn depend on culture. Adaptive strategies identified through the data analysis show a strong connection between natural and built landscapes, combined with the regional outdoor culture, the Garden City identity and the connections between rural and urban landscapes. The results also highlight that thermal comfort is an important but insufficient indicator of good microclimate design, as social and cultural values are important influences on climate experience and adaptation. Interpretive research is needed to fully understand urban comfort and to provide urban microclimate design solutions to enhance the use of public open spaces in cities undergoing change.

Audio, Radio New Zealand

Topics - appalling stories of Christchurch families living in garages and tents - even a couple renting a wash-house - are continuing to surface almost two years on from the February 2011 earthquake. Youth crime is described as "steadily falling" in New Zealand, with rates of police apprehensions and prosecutions of young people at record lows. Auckland Grammar has employed the services of a private investigator to check on parents trying to cheat on school zone boundaries.

Research papers, University of Canterbury Library

As the future of the world’s oil reserves becomes progressively more uncertain, it is becoming increasingly important that steps are taken to ensure that there are viable, attractive alternatives to travel by private motor vehicle. As with many of New Zealand’s major urban centres, Christchurch is still exceptionally reliant on private motor vehicles; although a significant proportion of the population indicate that they would like to cycle more, cycling is still an underutilised mode of transport. Following a series of fatal earthquakes that struck the city in 2010 and 2011, there has been the need to significantly redevelop much of the city’s horizontal infrastructure – subsequently providing the perfect platform for significant changes to be made to the road network. Many of the key planning frameworks governing the rebuild process have identified the need to improve Christchurch’s cycling facilities in order to boost cycling numbers and cyclist safety. The importance of considering future growth and travel patterns when planning for transport infrastructure has been highlighted extensively throughout literature. Accordingly, this study sought to identify areas where future cycle infrastructure development would be advantageous based on a number of population and employment projections, and likely future travel patterns throughout the city. Through the use of extensive GIS analysis, future population growth, employment and travel patterns for Christchurch city were examined in order to attain an understanding of where the current proposed major cycleways network could be improved, or extended. A range of data and network analysis were used to derive likely travel patterns throughout Christchurch in 2041. Trips were derived twice, once with a focus on simply finding the shortest route between each origin and destination, and then again with a focus on cyclist safety and areas where cyclists were unlikely to travel. It was found that although the proposed major cycleways network represents a significant step towards improving the cycling environment in Christchurch, there are areas of the city that will not be well serviced by the current proposed network in 2041. These include a number of key residential growth areas such as Halswell, Belfast and Prestons, along with a number of noteworthy key travel zones, particularly in areas close to the central city and key employment areas. Using network analysis, areas where improvements or extensions to the proposed network would be most beneficial were identified, and a number of potential extensions in a variety of areas throughout the city were added to the network of cycle ways. Although it has been found that filling small gaps in the network can have considerable positive outcomes, results from the prioritisation analysis suggested that initially in Christchurch demand is likely to be for more substantial extensions to the proposed major cycleways network.

Research papers, University of Canterbury Library

Picture this, you are relaxing at home enjoying the afternoon sun. It is another beautiful Christchurch day in late 2017. There is a knock at the door, you’ve been expecting it. It is a member of the Christchurch Health and Development Study, here to conduct your prearranged interview. The interview request did not come as a surprise of course, you have been participating in these interviews yourself sporadically throughout your adult life, and prior to that you attended many alongside your parents. In fact, you have been answering the studies interview your whole life. Transcripts of these interviews sit in the studies database alongside copies of school reports, health records and a wealth of other information. It has been this way since birth, since your mother was approached back in 1977, not long after you had arrived in this world, and asked if she would consent to participating in the study. She, along with many other Cantabrian new mothers from that year, agreed and the Christchurch Health and Development Study was born. Since then, these interviews have become a matter of routine for you. As life went on many things changed, but one thing that was constant was the sporadic visit from an interviewer of the study. The current interview is a little different from most of the others, however. Last time an interviewer visited in 2012, you were asked if you would like to conduct an earthquake-specific interview, you agreed. This time, the same question was asked. Why? Well because you were there that day of course. The day of the 22nd February 2011 when a major earthquake struck Canterbury. You were there in the centre of the city as buildings came crashing down and people ran for safety. You were there for the chaos. Your knee dully aches, it never did quite heal properly and strangely seems to flare up whenever you think back to that day. A lasting reminder. It is a difficult subject, but you agree to the second earthquake-specific interview. You understand the purpose of the study, and the value of the data collected. You take a sip of the cup of tea politely made upon the interviewer’s arrival, lean back into the comfort of your couch and cast your mind back to that fateful day. So, what does this study mean? Why still participate, all these years later? Over time it has become more apparent as to how valuable this information could be, considering all the experiences through the life course, and to think of the experiences that others in the cohort have had too. How differently have events affected people from all walks of life, who just so happened to be born within the same few months. We can use the data from this study to better understand situations when using life course characteristics which can hopefully influence decision making and population health within New Zealand.

Research papers, University of Canterbury Library

Research following the 2010-2011 Canterbury earthquakes investigated the minimum vertical reinforcement required in RC walls to generate well distributed cracking in the plastic hinge region. However, the influence of the loading sequence and rate has not been fully addressed. The new minimum vertical reinforcement limits in NZS 3101:2006 (Amendment 3) include consideration of the material strengths under dynamic load rates, but these provisions have not been validated at a member or system level. A series of tests were conducted on RC prisms to investigate the effect of loading rate and sequence on the local behaviour of RC members. Fifteen axially loaded RC prisms with the designs representing the end region of RC walls were tested under various loading rates to cover the range of pseudo-static and earthquake loading scenarios. These tests will provide substantial data for understanding the local behaviour of RC members, including hysteretic load-deformation behaviour, crack patterns, failure mode, steel strain, strain rate and ductility. Recommendations will be made regarding the effect of loading rate and reinforcement content on the cracking behaviour and ductility of RC members.

Research papers, The University of Auckland Library

The Catholic Cathedral of the Blessed Sacrament is a category 1 listed heritage building constructed largely of unreinforced stone masonry, and was significantly damaged in the recent Canterbury earthquakes. The building experienced ground shaking in excess of its capacity leading to block failures and partial collapse of parts of the building, which left the building standing but still posing a significant hazard. In this paper we discuss the approach to securing the building, and the interaction of the structural, heritage and safety demands involved in a dynamic seismic risk environment. We briefly cover the types of failures observed and the behaviour of the structure, and investigate the performance of both strengthened and un-strengthened parts of the building. Seismic strengthening options are investigated at a conceptual level. We draw conclusions as to how the building performed in the earthquakes, comment on the effectiveness of the strengthening and securing work and discuss the potential seismic strengthening methods.

Research papers, University of Canterbury Library

There is a relationship between inelastic deformation and energy dissipation in structures that are subjected to earthquake ground motions. Thus, if seismic energy dissipation can be achieved by means of a separate non-load bearing supplementary damping system, the load bearing structure can remain elastic with continuing serviceability following the design level earthquake. This research was carried out to investigate the advantages of using added damping in structures. The control system consists of passive friction dampers called ring spring dampers installed in the ground floor of the structure using a tendon to transmit the forces to the other parts of the structure. The ring springs dampers are friction devices consisting of inner and outer ring elements assembled to form a spring stack. External load applied to the spring produces sliding action across mating ring interfaces. The damping forces generated by the dampers and transferred in the supplemental system to the structure by the tendon and horizontal links oppose the internal loads. A four storey-two bay steel frame structure was used in the study. Experimental and analytical studies to investigate the effectiveness of a supplemental control system are presented. The model was subjected to a series of earthquake simulations on the shaking table in the Structural Laboratory of the Civil Engineering Department, at the University of Canterbury. The earthquake simulation tests have been performed on the structure both with and without the supplemental control system. The earthquake simulations were a series of gradually increasing intensity replications of two commonly used earthquake records. This thesis includes detailed description of the structural model, the supplemental control system, the ring springs dampers and the data obtained during the testing. Analyses were then carried out on a twelve storey framed structure to investigate the possible tendon arrangements and the size and type of dampers required to control the response of a real building. Guidelines for determining the appropriateness of including a supplemental damping system have been investigated. The main features of the supplemental control system adopted in this research are: • It is a passive control system with extreme reliability and having no dependence on external power sources to effect the control action. These power sources may not be available during a major earthquake. • Ring springs are steel friction devices capable of absorbing large amounts of input energy. No liquid leakage can occur and minimal maintenance is required for the ring spring dampers. • With a damper-tendon system, the distribution of the dampers throughout the structure is not so critical. Only one or two dampers are used to produce the damping forces needed, and forces are then transferred to the rest of the building by the tendon system. • It is a relatively inexpensive control system with a long useful life.

Audio, Radio New Zealand

National MP Gerry Brownlee says it's a great tragedy that the former chairman of government insurer Southern Response has been treated the way that he has. Ross Butler resigned on Tuesday night after a State Services Commission inquiry found Southern Response had broken its code of conduct and possibly the law, when it used private investigators to secretly record meetings of earthquake victims. The Minister for Christchurch Regeneration Megan Woods says Mr Butler was aware of what was going on, as was Mr Brownlee when he was a Minister.

Audio, Radio New Zealand

Topics - the latest twist in the Kim Dotcom saga is that the police have announced they're investigating the Government Communications Security Bureau's illegal surveillance of the internet mogul. New research has shown that membership of all mainstream Christian denominations has fallen to historic lows - except for Catholicism. New research has uncovered the role underground rock structures played in stopping the September 2010 Christchurch earthquake from linking up with the Port Hills faultline and causing greater damage to Christchurch.

Audio, Radio New Zealand

Topics - A couple of New Zealand women, determined to carry on clubbing with kids, have launched the first New Zealand-based"Baby Loves Disco"franchise in Auckland's Viaduct. The"sheer strength and power"of the September the 4th earthquake has more than doubled the number of reported supernatural events in Canterbury, according to a paranormal investigator. The 2010 Census of Women's Participation reveals that female participation in governance, professional and public life is slipping away - erasing gains made in the past decades.

Videos, UC QuakeStudies

A video of Press journalist Martin Van Beynen talking about the Canterbury Television Building which collapsed during the 22 February 2011 earthquake. Beynen investigates the construction manager of the building, Gerald Shirtcliff, who allegedly faked an engineering degree and stole the identity of an engineer he knew in South Africa. The video also includes footage of Shirtcliff giving evidence about the CTV Building at the Canterbury Earthquake Royal Commission.

Research papers, University of Canterbury Library

This paper presents a methodology by which both site-specific and spatially distributed ground motion intensity can be obtained immediately following an earthquake event. The methodology makes use of both prediction models for ground motion intensity and its correlation over spatial distances. A key benefit of the methodology is that the ground motion intensity at a given location is not a single value but a distribution of values. The distribution is comprised of both a mean and also standard deviation, with the standard deviation being a function of the distance to nearby strong motion stations. The methodology is illustrated for two applications. Firstly, maps of conditional peak ground acceleration (PGA) have been developed for the major events in the Canterbury earthquake sequence. It is illustrated how these conditional maps can be used for post-event evaluation of liquefaction triggering criteria which have been adopted by the Department of Building and Housing (DBH). Secondly, the conditional distribution of response spectral ordinates is obtained at a specific location for the purposes of determining appropriate ground motion records for use in seismic response analyses of important structures at locations where direct recordings are absent.

Research papers, Victoria University of Wellington

The suburb of New Brighton in Christchurch Aotearoa was once a booming retail sector until the end of its exclusivity to Saturday shopping in 1980 and the aftermath of the devastating 2011 Christchurch earthquake. The suburb of New Brighton was hit particularly hard and fell into economic collapse, partly brought on by the nature of its economic structure. This implosion created an urban crisis where people and businesses abandoned the suburb and its once-booming commercial economy. As a result, New Brighton has been left with the residue of abandoned infrastructure and commercial propaganda such as billboards, ATM machines, commercial facades, and shopping trolleys that as abandoned fragments, no longer contribute to culture, society and the economy. This design-led research investigation proposes to repurpose the broken objects that were left behind. By strategically selecting objects that are symbols of the root cause of the economic devastation, the repurposed and re-contextualised fragments will seek to allegorically expose the city’s destructive economic narrative, while providing a renewed sense of place identity for the people. This design-led thesis investigation argues that the seemingly innocuous icons of commercial industry, such as billboards, ATM machines, commercial facades, and shopping trolleys, are intended to act as lures to encourage people to spend money; ultimately, these urban and architectural lures can contribute to economic devastation. The aim of this investigation is to repurpose abandoned fragments of capitalist infrastructure in ways that can help to unveil new possibilities for a disrupted community and enhance their awareness of what led to the urban disruption. The thesis proposes to achieve this research aim by exploring three principal research objectives: 1) to assimilate and re-contextualise disconnected urban fragments into new architectural interventions; 2) to anthropomorphise these new interventions so that they are recognisable as architectural ‘inhabitants’, the storytellers of the urban context; and 3) to curate these new architectural interventions in ways that enable a community-scale allegorical and didactic experience to be recognised.

Research papers, University of Canterbury Library

Detailed studies on the sediment budget may reveal valuable insights into the successive build-up of the Canterbury Plains and their modification by Holocene fluvialaction connected to major braided rivers. Additionally, they bear implications beyond these fluvial aspects. Palaeoseismological studies claim to have detected signals of major Alpine Fault earthquakes in coastal environments along the eastern seaboard of the South Island (McFadgen and Goff, 2005). This requires high connectivity between the lower reaches of major braided rivers and their mountain catchments to generate immediate significant sediment pulses. It would be contradictory to the above mentioned hypothesis though. Obtaining better control on sediment budgets of braided rivers like the Waimakariri River will finally add significant value to multiple scientific and applied topics like regional resource management. An essential first step of sediment budget studies Is to systematically map the geomorphology, conventionally in the field and/or using remote-sensing applications, to localise, genetically identify, and classify landforms or entire toposequences of the area being investigated. In formerly glaciated mountain environments it is also indispensable to obtain all available chronological information supporting subsequent investigations.

Research papers, University of Canterbury Library

Structural members made of laminated veneer lumber (LVL) in combination with unbonded post-tensioning have recently been proposed, which makes it possible to design moment-resisting frames with longer spans for multi-storey timber buildings. It has been shown that prefabricated and prestressed timber structures can be designed to have excellent seismic resistance, with enhanced re-centring and energy dissipation characteristics. The post-tensioning provides re-centring capacity while energy is dissipated through yielding of mild steel dissipating devices. This paper summarizes an experimental investigation into the seismic response of LVL columns to bi-directional seismic loading, performed as part of a research programme on timber structures at the University of Canterbury. The experimental investigation includes testing under both quasi-static cyclic and pseudo-dynamic protocols. The results show excellent seismic performance, characterized by negligible damage of the structural members and small residual deformations, even under the combined effect of loading in two directions. Energy is dissipated mostly through yielding of external dissipators connecting the column and the foundation, which can be easily removed and replaced after an earthquake. Since post-tensioning can be economically performed on site, the system can be easily implemented in multi-storey timber buildings

Research papers, The University of Auckland Library

The 2010/2011 Canterbury earthquakes have provided a unique opportunity to investigate the seismic performance of both traditional and modern buildings constructed in New Zealand. It is critical that the observed performance is examined and compared against the expected levels of performance that are outlined by the Building Code and Design Standards. In particular, in recent years there has been a significant amount of research into the seismic behaviour of precast concrete floor systems and the robustness of the support connections as a building deforms during an earthquake. An investigation of precast concrete floor systems in Christchurch has been undertaken to assess both the performance of traditional and current design practice. The observed performance for each type of precast floor unit was collated from a number of post-earthquake recognisance activities and compared against the expected performance determined for previous experimental testing and analysis. Possible reasons for both the observed damage, and in some cases the lack of damage, were identified. This critical review of precast concrete floor systems will assist in determining the success of current design practice as well as identify any areas that require further research and/or changes to design standards.

Research papers, University of Canterbury Library

The lateral capacity of a conventional CLT shear wall is often governed by the strength and stiffness of its connections, which do not significantly utilize the in-plane strength of the CLT. Therefore, CLT shear walls are not yet being used efficiently in the construction of mass timber buildings due to a lack of research on high-capacity connections and alternative wall configurations. In this study, cyclic experiments were completed on six full-scale, 5-ply cantilever CLT shear walls with high-capacity hold-downs using mixed angle screws and bolts. All specimens exhibited significantly higher strength and stiffness than previously tested conventional CLT shear walls in the literature. The base connections demonstrated ductile failure modes through yielding of the hold-down connections. Based on the experimental results, numerical models were calibrated to investigate the seismic behaviour of CLT shear walls for prototype buildings of 3 and 6-storeys in Christchurch, NZ. As an alternative to cantilever (single) shear walls, a type of coupled wall with steel link beams between adjacent CLT wall piers was investigated. Effective coupling requires the link beam-to-wall connections to have adequate strength to ensure ductile link beam responses and adequate stiffness to yield the link beams at a relatively low inter-storey drift level. To this end, three beam-to-wall connection types were developed and cyclically tested to investigate their behaviour and feasibility. Based on the test results of the critical connection, a 3-storey, 2/3-scale coupled CLT wall specimen with three steel link beams and mixed angle screwed hold-downs was cyclically tested to evaluate its performance and experimentally validate the system concept. The test results showed a relatively high lateral strength compared to conventional CLT shear walls, as well as a high system ductility ratio of 7.6. Failure of the system was characterised by combined bending and withdrawal of the screws in the mixed angle screw hold-downs, yielding and eventual inelastic buckling of the steel link beams, CLT toe crushing, and local CLT delamination. Following the initial test, the steel link beams, mixed angle screw hold-downs, and damaged CLT regions were repaired, then the wall specimen was re-tested. The repaired wall behaved similarly to the original test and exhibited slightly higher energy dissipation and peak strength, but marginally more rapid strength deterioration under cyclic loading. Several hybrid coupled CLT shear walls were numerically modelled and calibrated based on the results of the coupled wall experiments. Pushover analyses were conducted on a series of configurations to validate a capacity design method for the system and to investigate reasonable parameter values for use in the preliminary design of the system. Additionally, an iterative seismic design method was proposed and used to design sample buildings of 6, 8, and 10-storeys using both nonlinear pushover and nonlinear time history analyses to verify the prototype designs. Results of the sample building analyses demonstrated adequate seismic behaviour and the proposed design parameters were found to be appropriate. In summary, high-capacity CLT shear walls can be used for the resistance of earthquakes by using stronger base connections and coupled wall configurations. The large-scale experimental testing in this study has demonstrated that both cantilever and coupled CLT shear walls are feasible LLRSs which can provide significantly greater lateral strength, stiffness, and energy dissipation than conventional CLT shear wall configurations.