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Audio, Radio New Zealand

A magnitude six earthquake which struck in Canterbury just before quarter-past-nine Wednesday morning has left some nearby residents feeling a bit shaken. The quake, which struck 45 kilometres north of Geraldine at a depth of ten kilometres, was located in the Southern Alps, away from populated areas. It was widely felt in Geraldine, Timaru and Temuka - though there are no reports of serious damage or injury. Timaru District Council says it's closing a stadium and other facilities for assessment. Two people who experienced the quake, Janene Adams who's deputy chair of the Geraldine Community Board, and from further north, and the operator of the Mount Somers Holiday Park, Maureen Meanwell, spoke with Charlotte Cook

Research papers, The University of Auckland Library

Reinforced concrete buildings that satisfied modern seismic design criteria generally behaved as expected during the recent Canterbury and Kaikoura earthquakes in New Zealand, forming plastic hinges in intended locations. While this meant that life-safety performance objectives were met, widespread demolition and heavy economic losses took place in the aftermath of the earthquakes.The Christchurch central business district was particularly hard hit, with over 60% of the multistorey reinforced concrete buildings being demolished. A lack of knowledge on the post-earthquake residual capacity of reinforced concrete buildings was a contributing factor to the mass demolition.Many aspects related to the assessment of earthquake-damaged reinforced concrete buildings require further research. This thesis focusses on improving the state of knowledge on the post earthquakeresidual capacity and reparability of moderately damaged plastic hinges, with an emphasis on plastic hinges typical of modern moment frame structures. The repair method focussed on is epoxy injection of cracks and patching of spalled concrete. A targeted test program on seventeen nominally identical large-scale ductile reinforced concrete beams, three of which were repaired by epoxy injection following initial damaging loadings, was conducted to support these objectives. Test variables included the loading protocol, the loading rate, and the level of restraint to axial elongation.The information that can be gleaned from post-earthquake damage surveys is investigated. It is shown that residual crack widths are dependent on residual deformations, and are not necessarily indicative of the maximum rotation demands or the plastic hinge residual capacity. The implications of various other types of damage typical of beam and column plastic hinges are also discussed.Experimental data are used to demonstrate that the strength and deformation capacity of plastic hinges with modern seismic detailing are often unreduced as a result of moderate earthquake induced damage, albeit with certain exceptions. Special attention is given to the effects of prior yielding of the longitudinal reinforcement, accounting for the low-cycle fatigue and strain ageing phenomena. A material-level testing program on the low-cycle fatigue behaviour of grade 300E reinforcing steel was conducted to supplement the data available in the literature.A reduction in stiffness, relative to the initial secant stiffness to yield, occurs due to moderate plastic hinging damage. This reduction in stiffness is shown to be correlated with the ductility demand,and a proposed model gives a conservative lower-bound estimate of the residual stiffness following an arbitrary earthquake-type loading. Repair by epoxy injection is shown to be effective in restoring the majority of stiffness to plastic hinges in beams. Epoxy injection is also shown to have implications for the residual strength and elongation characteristics of repaired plastic hinges.

Research papers, University of Canterbury Library

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).

Research papers, University of Canterbury Library

Study region: Christchurch, New Zealand. Study focus: Low-lying coastal cities worldwide are vulnerable to shallow groundwater salinization caused by saltwater intrusion and anthropogenic activities. Shallow groundwater salinization can have cascading negative impacts on municipal assets, but this is rarely considered compared to impacts of salinization on water supply. Here, shallow groundwater salinity was sampled at high spatial resolution (1.3 piezometer/km2 ), then mapped and spatially interpolated. This was possible due to a uniquely extensive set of shallow piezometers installed in response to the 2010–11 Canterbury Earthquake Sequence to assess liquefaction risk. The municipal assets located within the brackish groundwater areas were highlighted. New hydrological insights for the region: Brackish groundwater areas were centred on a spit of coastal sand dunes and inside the meander of a tidal river with poorly drained soils. The municipal assets located within these areas include: (i) wastewater and stormwater pipes constructed from steel-reinforced concrete, which, if damaged, are vulnerable to premature failure when exposed to chloride underwater, and (ii) 41 parks and reserves totalling 236 ha, within which salt-intolerant groundwater-dependent species are at risk. This research highlights the importance of determining areas of saline shallow groundwater in low-lying coastal urban settings and the co-located municipal assets to allow the prioritisation of sites for future monitoring and management.

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.

Research papers, University of Canterbury Library

The 14 November 2016 Kaikōura earthquake had major impacts on New Zealand's transport system. Road, rail and port infrastructure was damaged, creating substantial disruption for transport operators, residents, tourists, and business owners in the Canterbury, Marlborough and Wellington regions, with knock-on consequences elsewhere. During both the response and recovery phases, a large amount of information and data relating to the transport system was generated, managed, analysed, and exchanged within and between organisations to assist decision making. To improve information and data exchanges and related decision making in the transport sector during future events and guide new resilience strategies, we present key findings from a recent post-earthquake assessment. The research involved 35 different stakeholder groups and was conducted for the Ministry of Transport. We consider what transport information was available, its usefulness, where it was sourced from, mechanisms for data transfer between organisations, and suggested approaches for continued monitoring.

Research papers, University of Canterbury Library

One of the most controversial issues highlighted by the 2010-2011 Christchurch earthquake series and more recently the 2016 Kaikoura earthquake, has been the evident difficulty and lack of knowledge and guidelines for: a) evaluation of the residual capacity damaged buildings to sustain future aftershocks; b) selection and implementation of a series of reliable repairing techniques to bring back the structure to a condition substantially the same as prior to the earthquake; and c) predicting the cost (or cost-effectiveness) of such repair intervention, when compared to fully replacement costs while accounting for potential aftershocks in the near future. As a result of such complexity and uncertainty (i.e., risk), in combination with the possibility (unique in New Zealand when compared to most of the seismic-prone countries) to rely on financial support from the insurance companies, many modern buildings, in a number exceeding typical expectations from past experiences at an international level, have ended up being demolished. This has resulted in additional time and indirect losses prior to the full reconstruction, as well as in an increase in uncertainty on the actual relocation of the investment. This research project provides the main end-users and stakeholders (practitioner engineers, owners, local and government authorities, insurers, and regulatory agencies) with comprehensive evidence-based information to assess the residual capacity of damage reinforced concrete buildings, and to evaluate the feasibility of repairing techniques, in order to support their delicate decision-making process of repair vs. demolition or replacement. Literature review on effectiveness of epoxy injection repairs, as well as experimental tests on full-scale beam-column joints shows that repaired specimens have a reduced initial stiffness compared with the undamaged specimen, with no apparent strength reduction, sometimes exhibiting higher displacement ductility capacities. Although the bond between the steel and concrete is only partially restored, it still allows the repaired specimen to dissipate at least the same amount of hysteretic energy. Experimental tests on buildings subjected to earthquake loading demonstrate that even for severe damage levels, the ability of the epoxy injection to restore the initial stiffness of the structure is significant. Literature review on damage assessment and repair guidelines suggests that there is consensus within the international community that concrete elements with cracks less than 0.2 mm wide only require cosmetic repairs; epoxy injection repairs of cracks less and 2.0 mm wide and concrete patching of spalled cover concrete (i.e., minor to moderate damage) is an appropiate repair strategy; and for severe damaged components (e.g., cracks greater than 2.0 mm wide, crushing of the concrete core, buckling of the longitudinal reinforcement) local replacement of steel and/or concrete in addition to epoxy crack injection is more appropriate. In terms of expected cracking patterns, non-linear finite element investigations on well-designed reinforced concrete beam-to-column joints, have shown that lower number of cracks but with wider openings are expected to occur for larger compressive concrete strength, f’c, and lower reinforcement content, ρs. It was also observed that the tensile concrete strength, ft, strongly affects the expected cracking pattern in the beam-column joints, the latter being more uniformly distributed for lower ft values. Strain rate effects do not seem to play an important role on the cracking pattern. However, small variations in the cracking pattern were observed for low reinforcement content as it approaches to the minimum required as per NZS 3101:2006. Simple equations are proposed in this research project to relate the maximum and residual crack widths with the steel strain at peak displacement, with or without axial load. A literature review on fracture of reinforcing steel due to low-cycle fatigue, including recent research using steel manufactured per New Zealand standards is also presented. Experimental results describing the influence of the cyclic effect on the ultimate strain capacity of the steel are also discussed, and preliminary equations to account for that effect are proposed. A literature review on the current practice to assess the seismic residual capacity of structures is also presented. The various factors affecting the residual fatigue life at a component level (i.e., plastic hinge) of well-designed reinforced concrete frames are discussed, and equations to quantify each of them are proposed, as well as a methodology to incorporate them into a full displacement-based procedure for pre-earthquake and post-earthquake seismic assessment.

Research papers, The University of Auckland Library

As part of the ‘Project Masonry’ Recovery Project funded by the New Zealand Natural Hazards Research Platform, commencing in March 2011, an international team of researchers was deployed to document and interpret the observed earthquake damage to masonry buildings and to churches as a result of the 22nd February 2011 Christchurch earthquake. The study focused on investigating commonly encountered failure patterns and collapse mechanisms. A brief summary of activities undertaken is presented, detailing the observations that were made on the performance of and the deficiencies that contributed to the damage to approximately 650 inspected unreinforced clay brick masonry (URM) buildings, to 90 unreinforced stone masonry buildings, to 342 reinforced concrete masonry (RCM) buildings, to 112 churches in the Canterbury region, and to just under 1100 residential dwellings having external masonry veneer cladding. Also, details are provided of retrofit techniques that were implemented within relevant Christchurch URM buildings prior to the 22nd February earthquake. In addition to presenting a summary of Project Masonry, the broader research activity at the University of Auckland pertaining to the seismic assessment and improvement of unreinforced masonry buildings is outlined. The purpose of this outline is to provide an overview and bibliography of published literature and to communicate on-going research activity that has not yet been reported in a complete form. http://sesoc.org.nz/conference/programme.pdf

Research papers, University of Canterbury Library

Seismic isolation is an effective technology for significantly reducing damage to buildings and building contents. However, its application to light-frame wood buildings has so far been unable to overcome cost and technical barriers such as susceptibility to movement during high-wind loading. The precursor to research in the field of isolation of residential buildings was the 1994 Northridge Earthquake (6.7 MW) in the United States and the 1995 Kobe Earthquake (6.9 MW) in Japan. While only a small number of lives were lost in residential buildings in these events, the economic impact was significant with over half of earthquake recovery costs given to repair and reconstruction of residential building damage. A value case has been explored to highlight the benefits of seismically isolated residential buildings compared to a standard fixed-base dwellings for the Wellington region. Loss data generated by insurance claim information from the 2011 Christchurch Earthquake has been used by researchers to determine vulnerability functions for the current light-frame wood building stock. By further considering the loss attributed to drift and acceleration sensitive components, and a simplified single degree of freedom (SDOF) building model, a method for determining vulnerability functions for seismic isolated buildings was developed. Vulnerability functions were then applied directly in a loss assessment using the GNS developed software, RiskScape. Vulnerability was shown to dramatically reduce for isolated buildings compared to an equivalent fixed-base building and as a result, the monetary savings in a given earthquake scenario were significant. This work is expected to drive further interest for development of solutions for the seismic isolation of residential dwellings, of which one option is further considered and presented herein.

Research papers, University of Canterbury Library

In this thesis, focus is given to develop methodologies for rapidly estimating specific components of loss and downtime functions. The thesis proposes methodologies for deriving loss functions by (i) considering individual component performance; (ii) grouping them as per their performance characteristics; and (iii) applying them to similar building usage categories. The degree of variation in building stock and understanding their characteristics are important factors to be considered in the loss estimation methodology and the field surveys carried out to collect data add value to the study. To facilitate developing ‘downtime’ functions, this study investigates two key components of downtime: (i) time delay from post-event damage assessment of properties; and (ii) time delay in settling the insurance claims lodged. In these two areas, this research enables understanding of critical factors that influence certain aspects of downtime and suggests approaches to quantify those factors. By scrutinising the residential damage insurance claims data provided by the Earthquake Commission (EQC) for the 2010- 2011 Canterbury Earthquake Sequence (CES), this work provides insights into various processes of claims settlement, the time taken to complete them and the EQC loss contributions to building stock in Christchurch city and Canterbury region. The study has shown diligence in investigating the EQC insurance claim data obtained from the CES to get new insights and build confidence in the models developed and the results generated. The first stage of this research develops contribution functions (probabilistic relationships between the expected losses for a wide range of building components and the building’s maximum response) for common types of claddings used in New Zealand buildings combining the probabilistic density functions (developed using the quantity of claddings measured from Christchurch buildings), fragility functions (obtained from the published literature) and cost functions (developed based on inputs from builders) through Monte Carlo simulations. From the developed contribution functions, glazing, masonry veneer, monolithic and precast concrete cladding systems are found to incur 50% loss at inter-storey drift levels equal to 0.027, 0.003, 0.005 and 0.011, respectively. Further, the maximum expected cladding loss for glazing, masonry veneer, monolithic, precast concrete cladding systems are found to be 368.2, 331.9, 365.0, and 136.2 NZD per square meter of floor area, respectively. In the second stage of this research, a detailed cost breakdown of typical buildings designed and built for different purposes is conducted. The contributions of structural and non- structural components to the total building cost are compared for buildings of different usages, and based on the similar ratios of non-structural performance group costs to the structural performance group cost, four-building groups are identified; (i) Structural components dominant group: outdoor sports, stadiums, parkings and long-span warehouses, (ii) non- structural drift-sensitive components dominant group: houses, single-storey suburban buildings (all usages), theatres/halls, workshops and clubhouses, (iii) non-structural acceleration- sensitive components dominant group: hospitals, research labs, museums and retail/cold stores, and (iv) apartments, hotels, offices, industrials, indoor sports, classrooms, devotionals and aquariums. By statistically analysing the cost breakdowns, performance group weighting factors are proposed for structural, and acceleration-sensitive and drift-sensitive non-structural components for all four building groups. Thus proposed building usage groupings and corresponding weighting factors facilitate rapid seismic loss estimation of any type of building given the EDPs at storey levels are known. A model for the quantification of post-earthquake inspection duration is developed in the third stage of this research. Herein, phase durations for the three assessment phases (one rapid impact and two rapid building) are computed using the number of buildings needing inspections, the number of engineers involved in inspections and a phase duration coefficient (which considers the median building inspection time, efficiency of engineer and the number of engineers involved in each assessment teams). The proposed model can be used: (i) by national/regional authorities to decide the length of the emergency period following a major earthquake, and estimate the number of engineers required to conduct a post-earthquake inspection within the desired emergency period, and (ii) to quantify the delay due to inspection for the downtime modelling framework. The final stage of this research investigates the repair costs and insurance claim settlement time for damaged residential buildings in the 2010-2011 Canterbury earthquake sequence. Based on the EQC claim settlement process, claims are categorized into three groups; (i) Small Claims: claims less than NZD15,000 which were settled through cash payment, (ii) Medium Claims: claims less than NZD100,000 which were managed through Canterbury Home Repair Programme (CHRP), and (iii) Large Claims: claims above NZD100,000 which were managed by an insurance provider. The regional loss ratio (RLR) for greater Christchurch for three events inducing shakings of approximate seismic intensities 6, 7, and 8 are found to be 0.013, 0.066, and 0.171, respectively. Furthermore, the claim duration (time between an event and the claim lodgement date), assessment duration (time between the claim lodgement day and the most recent assessment day), and repair duration (time between the most recent assessment day and the repair completion day) for the insured residential buildings in the region affected by the Canterbury earthquake sequence is found to be in the range of 0.5-4 weeks, 1.5- 5 months, and 1-3 years, respectively. The results of this phase will provide useful information to earthquake engineering researchers working on seismic risk/loss and insurance modelling.

Research papers, University of Canterbury Library

The effects of soil-foundation-structure interaction (SFSI) have been a topic of discussion amongst the structural and geotechnical community for many decades. The complexity of the mechanisms, as well as the need for inter-disciplinary knowledge of geotechnical and structural dynamics has plagued the advancement and the consequent inclusion of SFSI effects in design. A rigorous performance-based design methodology should not just consider the performance of the superstructure but the supporting foundation system as well. Case studies throughout history (eg. Kobe 1995, Kocaeli 1999 and Christchurch earthquakes 2010-2011) have demonstrated that a poor performance at the foundation level can result in a full demolition of the structure and, in general terms, that the extent of damage to, and repairability of, the building system as a whole, is given by the combination of the damage to the soil, foundation and superstructure. The lack of consideration of the modifying factors of SFSI and an absence of intuitive performance levels for controlling foundation and soil behaviour under seismic loads has resulted in inadequate designs for buildings sited on soft soil. For engineers to be satisfied that their designs meet the given performance levels they must first, understand how SFSI affects the overall system performance and secondly have tools available to adequately account for it in their design/assessment. This dissertation presents an integrated performance-based design procedure for buildingfoundation systems that considers all of the major mechanisms of SFSI. A new soil-foundation macro-element model was implemented into a nonlinear finite element software and validated against several experimental tests. The numerical model was used to provide insights in to the mechanisms of SFSI and statistical analysis on the results yielded simple expressions that allow the behaviour to be quantified. Particular attention was paid to the effects of shear force on the foundation response and the quantification of the rocking mode of response. The residual deformations of the superstructure and distribution of forces up the structure were also investigated. All of the major SFSI mechanisms are discussed in detail and targeted numerical studies are used to explain and demonstrate concepts. The design procedure was validated through the design and assessment of a series of concrete buildings that were designed to account for the effects of SFSI.

Audio, Radio New Zealand

ANDREW LITTLE to the Prime Minister: What are the priorities for the Government in assisting communities affected by yesterday’s earthquake? MATT DOOCEY to the Minister of Finance: What advice has he received about the economic impact of the Kaikōura earthquake? EUGENIE SAGE to the Minister of Transport: What updates can he give on the transport sector’s response to earthquake damage to State Highway 1 and the rail line between Seddon and Cheviot? GRANT ROBERTSON to the Minister of Finance: What is his initial assessment of the fiscal impact of yesterday morning’s earthquake and what, if any, new or changed Budget allocations is he considering in response to the earthquake? PAUL FOSTER-BELL to the Minister of Civil Defence: How is the Government supporting people affected by the Kaikōura earthquake? RON MARK to the Minister of Civil Defence: Can the Government assure New Zealanders on our level of preparedness for all natural disasters? SUE MORONEY to the Minister of Transport: What roads and public transport services are currently not operational following damage from the earthquake yesterday and when is it expected access and services will be restored? BRETT HUDSON to the Minister of Transport: What action is the Government taking to repair damaged transport infrastructure following the Kaikōura earthquake? GARETH HUGHES to the Minister of Broadcasting: Will she join with me to acknowledge the work of all media in New Zealand, which is so important in times of natural disaster and crisis; if so, will she consider increasing our public broadcaster Radio New Zealand’s funding in Budget 2017? CLAYTON MITCHELL to the Minister of Civil Defence: What progress has been made, if any, on new civil defence legislation which focuses on large and significant events such as the Christchurch and Kaikōura earthquakes? ALASTAIR SCOTT to the Minister of Health: What updates has he received on the Government’s health response to the Kaikōura earthquake? CLARE CURRAN to the Minister of Civil Defence: What actions have been taken by Civil Defence to ensure those people in the areas worst hit by the earthquake have enough food, clothing, water, and shelter?

Research papers, University of Canterbury Library

Base isolation is an incredibly effective technology used in seismic regions throughout the world to limit structural damage and maintain building function, even after severe earthquakes. However, it has so far been underutilised in light-frame wood construction due to perceived cost issues and technical problems, such as a susceptibility to movement under strong wind loads. Light-frame wood buildings make up the majority of residential construction in New Zealand and sustained significant damage during the 2010-2011 Canterbury earthquake sequence, yet the design philosophy has remained largely unchanged for years due to proven life-safety performance. Recently however, with the advent of performance based earthquake engineering, there has been a renewed focus on performance factors such as monetary loss that has driven a want for higher performing residential buildings. This research develops a low-cost approach for the base isolation of light-frame wood buildings using a flat-sliding friction base isolation system, which addresses the perceived cost and technical issues, and verifies the seismic performance through physical testing on the shake table at the University of Canterbury. Results demonstrate excellent seismic performance with no structural damage reported despite a large number of high-intensity earthquake simulations. Numerical models are subsequently developed and calibrated to New Zealand light-frame wood building construction approaches using state-of-the-art wood modelling software, Timber3D. The model is used to accurately predict both superstructure drift and acceleration demand parameters of fixed-base testing undertaken after the base isolation testing programme is completed. The model development allows detailed cost analyses to be undertaken within the performance based earthquake engineering framework that highlights the monetary benefits of using base isolation. Cost assessments indicate the base isolation system is only 6.4% more compared to the traditional fixed-base system. Finally, a design procedure is recommended for base isolated light-frame wood buildings that is founded on the displacement based design (DBD) approach used in the United States and New Zealand. Nonlinear analyses are used to verify the DBD method which indicate its suitability.

Research papers, The University of Auckland Library

Many large-scale earthquakes all over the world have highlighted the impact of soil liquefaction to the built environment, but the scale of liquefaction-induced damage experienced in Christchurch and surrounding areas following the 2010-2011 Canterbury earthquake sequence (CES) was unparalleled, especially in terms of impact to an urban area. The short time interval between the large earthquakes presented a very rare occasion to examine liquefaction mechanism in natural deposits. The re-liquefaction experienced by the city highlighted the high liquefaction susceptibility of soil deposits in Christchurch, and presented a very challenging problem not only to the local residents but to the geotechnical engineering profession. This paper summarises the lessons learned from CES, and the impacts of the observations made to the current practice of liquefaction assessment and mitigation.

Research papers, The University of Auckland Library

Test results are presented for wall-diaphragm plate anchor connections that were axially loaded to rupture. These connection samples were extracted post-earthquake by sorting through the demolition debris from unreinforced masonry (URM) buildings damaged in the Christchurch earthquakes. Unfortunately the number of samples available for testing was small due to the difficulties associated with sample collection in an environment of continuing aftershocks and extensive demolition activity, when personal safety combined with commercial activity involving large demolition machinery were imperatives that inhibited more extensive sample collection for research purposes. Nevertheless, the presented data is expected to be of assistance to structural engineers undertaking seismic assessment of URM buildings that have existing wall-diaphragm anchor plate connections installed, where it may be necessary to estimate the capacity of the existing connection as an important parameter linked with determining the current seismic capacity of the building and therefore influencing the decision regarding whether supplementary connections should be installed.

Research papers, The University of Auckland Library

Following the 2010/2011 Canterbury earthquakes a detailed campaign of door to door assessments was conducted in a variety of areas of Christchurch to establish the earthquake performance of residential dwellings having masonry veneer as an external cladding attached to a lightweight timber framing system. Specifically, care was taken to include regions of Christchurch which experienced different levels of earthquake shaking in order to allow comparison between the performance of different systems and different shaking intensities. At the time of the inspections the buildings in the Christchurch region had been repeatedly subjected to large earthquakes, presenting an opportunity for insight into the seismic performance of masonry veneer cladding. In total just under 1100 residential dwellings were inspected throughout the wider Christchurch area, of which 24% were constructed using the older nail-on veneer tie system (prior to 1996) and 76% were constructed using screw fixed ties to comply with the new 1996 standards revision (post-1996), with 30% of all inspected houses being of two storey construction. Of the inspected dwellings 27% had some evidence of liquefaction, ground settlement or lateral spreading. Data such as damage level, damage type, crack widths, level of repair required and other parameters were collected during the survey. A description of the data collection processes and a snapshot of the analysis results are presented within. http://15ibmac.com/home/

Research papers, University of Canterbury Library

The Canterbury earthquakes of 2010 and 2011 caused significant damage and disruption to the city of Christchurch, New Zealand. A Royal Commission was established to report on the causes of building failure as a result of the earthquakes as well as look at the legal and best-practice requirements for buildings in New Zealand Central Business Districts. The Royal Commission made 189 recommendations on a variety of matters including managing damaged buildings after an earthquake, the adequacy of building codes and standards, and the processes of seismic assessments of existing buildings to determine their earthquake vulnerability. In response the Ministry of Business, Innovation and Employment, the agency responsible for administering building regulation in New Zealand, established a work programme to assist with the Canterbury rebuild and to implement the lessons learned throughout New Zealand. The five primary work streams in the programme are: • Facilitating the Canterbury Rebuild • Structural Performance and Design Standards • Geotechnical and structural guidance • Existing Building Resilience • Post Disaster Building Management This paper provides more detail on each of the work streams. There has been significant collaboration between the New Zealand Government and the research community, technical societies, and engineering consultants, both within New Zealand and internationally, to deliver the programme and improve the resilience of the New Zealand built environment. This has presented major challenges for an extremely busy industry in the aftermath of the Canterbury earthquakes. The paper identifies the items of work that have been completed and the work that is still in progress at the time of writing.

Research papers, University of Canterbury Library

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

Research papers, University of Canterbury Library

Natural disasters are increasingly disruptive events that affect livelihoods, organisations, and economies worldwide. Research has identified the impacts and responses of organisations to different types of natural disasters, and have outlined factors, such as industry sector, that are important to organisational vulnerability and resilience. One of the most costly types of natural disasters in recent years has been earthquakes, and yet to date, the majority of studies have focussed on the effects of earthquakes in urban areas, while rural organisational impact studies have primarily focused on the effects of meteorological and climatic driven hazards. As a result, the likely impacts of an earthquake on rural organisations in a developed context is unconstrained in the literature. In countries like New Zealand, which have major earthquakes and agricultural sectors that are significant contributors to the economy, it is important to know what impacts an earthquake event would have on the rural industries, and how these impacts compare to that of a more commonly analysed, high-frequency event. In September of 2010, rural organisations in Canterbury experienced the 4 September 2010 Mw 7.1 `Darfield' earthquake and the associated aftershocks, which came to be known as the Canterbury earth- quake sequence. The earthquake sequence caused intense ground shaking, creating widespread critical service outages, structural and non-structural damage to built infrastructure, as well as ground surface damage from ooding, liquefaction and surface rupture. Concurrently on September 18 2010, rural organisations in Southland experienced an unseasonably late snowstorm and cold weather snap that brought prolonged sub-zero temperatures, high winds and freezing rain, damaging structures in the City of Invercargill and causing widespread livestock losses and production decreases across the region. This thesis documents the effects of the Canterbury earthquake sequence and Southland snowstorm on farming and rural non-farming organisations, utilizing comparable methodologies to analyse rural organisational impacts, responses and recovery strategies to natural disasters. From the results, a short- term impact assessment methodology is developed for multiple disasters. Additionally, a regional asset repair cost estimation model is proposed for farming organisations following a major earthquake event, and the use of social capital in rural organisational recovery strategies following natural disasters is analysed.

Research papers, University of Canterbury Library

Recently developed performance-based earthquake engineering framework, such as one provided by PEER (Deierlein et al. 2003), assist in the quantification in terms of performance such as casualty, monetary losses and downtime. This opens up the opportunity to identify cost-effective retrofit/rehabilitation strategies by comparing upfront costs associated with retrofit with the repair costs that can be expected over time. This loss assessment can be strengthened by learning from recent earthquakes, such as the 2010 Canterbury and 2016 Kaikoura earthquakes. In order to investigate which types of retrofit/rehabilitation strategies may be most cost-effective, a case study building was chosen for this research. The Pacific Tower, a 22-storey EBF apartment located within the Christchurch central business district (CBD), was damaged and repaired during the 2010 Canterbury earthquake series. As such, by taking hazard levels accordingly (i.e. to correspond to the Christchurch CBD), modelling and analysing the structure, and considering the vulnerability and repair costs of its different components, it is possible to predict the expected losses of the aforementioned building. Using this information, cost-effective retrofit/rehabilitation strategy can be determined. This research found that more often than not, it would be beneficial to improve the performance of valuable non-structural components, such as partitions. Although it is true that improving such elements will increase the initial costs, over time, the benefits gained from reduced losses should be expected to overcome the initial costs. Aftershocks do increase the predicted losses of a building even in lower intensities due to the fact that non-structural components can get damaged at such low intensities. By comparing losses computed with and without consideration of aftershocks for a range of historical earthquakes, it was found that the ratio between losses due to main shock with aftershocks to the losses due to the main shock only tended to increase with increasing main shock magnitude. This may be due to the fact that larger magnitude earthquakes tend to generate larger magnitude aftershocks and as those aftershocks happen within a region around the main shock, they are more likely to cause intense shaking and additional damage. In addition to this observation, it was observed that the most significant component of loss of the case study building was the non-structural partition walls.

Research Papers, Lincoln University

Study region: Christchurch, New Zealand. Study focus: Low-lying coastal cities worldwide are vulnerable to shallow groundwater salinization caused by saltwater intrusion and anthropogenic activities. Shallow groundwater salinization can have cascading negative impacts on municipal assets, but this is rarely considered compared to impacts of salinization on water supply. Here, shallow groundwater salinity was sampled at high spatial resolution (1.3 piezometer/km²), then mapped and spatially interpolated. This was possible due to a uniquely extensive set of shallow piezometers installed in response to the 2010–11 Canterbury Earthquake Sequence to assess liquefaction risk. The municipal assets located within the brackish groundwater areas were highlighted. New hydrological insights for the region: Brackish groundwater areas were centred on a spit of coastal sand dunes and inside the meander of a tidal river with poorly drained soils. The municipal assets located within these areas include: (i) wastewater and stormwater pipes constructed from steel-reinforced concrete, which, if damaged, are vulnerable to premature failure when exposed to chloride underwater, and (ii) 41 parks and reserves totalling 236 ha, within which salt-intolerant groundwater-dependent species are at risk. This research highlights the importance of determining areas of saline shallow groundwater in low-lying coastal urban settings and the co-located municipal assets to allow the prioritisation of sites for future monitoring and management.

Images, Alexander Turnbull Library

Someone in a car full of passengers who represent '10,000 residents' says 'For Pete's sake... Are they ever going to change?' Spider webs have been spun between the car and the road as the car waits at a traffic light that represents the 'land report' and is stuck on orange. Context - Context - On Thursday 23 June Prime Minister John Key, Canterbury Earthquake Recovery Minister Gerry Brownlee and representatives from engineering consultants Tonkin & Taylor announced the first part of the Government's long-awaited land report that revealed the fate of up to 5000 quake-damaged homes. These homes were in the 'red zone'. But 10,500 owners in the orange zone were left in limbo, with their properties requiring further assessment. The areas included Kaiapoi, Pines Beach, Brooklands, Spencerville, Parklands and Queenspark (www.rebuildchristchurch.co.nz 6 July 2011)) Quantity: 1 digital cartoon(s).

Research papers, The University of Auckland Library

The research presented in this thesis investigated the environmental impacts of structural design decisions across the life of buildings located in seismic regions. In particular, the impacts of expected earthquake damage were incorporated into a traditional life cycle assessment (LCA) using a probabilistic method, and links between sustainable and resilient design were established for a range of case-study buildings designed for different seismic performance objectives. These links were quantified using a metric herein referred to as the seismic carbon risk, which represents the expected environmental impacts and resource use indicators associated with earthquake damage during buildings’ life. The research was broken into three distinct parts: (1) a city-level evaluation of the environmental impacts of demolitions following the 2010/2011 Canterbury earthquake sequence in New Zealand, (2) the development of a probabilistic framework to incorporate earthquake damage into LCA, and (3) using case-study buildings to establish links between sustainable and resilient design. The first phase of the research focused on the environmental impacts of demolitions in Christchurch, New Zealand following the 2010/2011 Canterbury Earthquake Sequence. This large case study was used to investigate the environmental impact of the demolition of concrete buildings considering the embodied carbon and waste stream distribution. The embodied carbon was considered here as kilograms of CO2 equivalent that occurs on production, construction, and waste management stage. The results clearly demonstrated the significant environmental impacts that can result from moderate and large earthquakes in urban areas, and the importance of including environmental considerations when making post-earthquake demolition decisions. The next phase of the work introduced a framework for incorporating the impacts of expected earthquake damage based on a probabilistic approach into traditional LCA to allow for a comparison of seismic design decisions using a carbon lens. Here, in addition to initial construction impacts, the seismic carbon risk was quantified, including the impacts of seismic repair activities and total loss scenarios assuming reconstruction in case of non-reparability. A process-based LCA was performed to obtain the environmental consequence functions associated with structural and non-structural repair activities for multiple environmental indicators. In the final phase of the work, multiple case-study buildings were used to investigate the seismic consequences of different structural design decisions for buildings in seismic regions. Here, two case-study buildings were designed to multiple performance objectives, and the upfront carbon costs, and well as the seismic carbon risk across the building life were compared. The buildings were evaluated using the framework established in phase 2, and the results demonstrated that the seismic carbon risk can significantly be reduced with only minimal changes to the upfront carbon for buildings designed for a higher base shear or with seismic protective systems. This provided valuable insight into the links between resilient and sustainable design decisions. Finally, the results and observations from the work across the three phases of research described above were used to inform a discussion on important assumptions and topics that need to be considered when quantifying the environmental impacts of earthquake damage on buildings. These include: selection of a non-repairable threshold (e.g. a value beyond which a building would be demolished rather than repaired), the time value of carbon (e.g. when in the building life the carbon is released), the changing carbon intensity of structural materials over time, and the consideration of deterministic vs. probabilistic results. Each of these topics was explored in some detail to provide a clear pathway for future work in this area.

Research papers, University of Canterbury Library

An as-built reinforced concrete (RC) frame building designed and constructed according to pre-1970s code design construction practice has been recently tested on the shake table at the University of Canterbury. The specimen, 1/2.5 scaled version of the original prototype, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. Following the benchmark test, a retrofit intervention has been proposed to rehabilitate the tested specimen. In this paper, detailed information on the assessment and design of the seismic retrofit procedure using GFRP (glass fibre reinforced polymer) materials is given for the whole frame. Hierarchy of strength and sequence of events (damage mechanisms) in the panel zone region are evaluated using a moment-axial load (M-N) interaction performance domain, according to a performance-based retrofit philosophy. Specific limit states or design objectives are targeted with attention given to both strength and deformation limits. In addition, an innovative retrofit solution using FRP anchor dowels for the corner beam-column joints with slabs is proposed. Finally, in order to provide a practical tool for engineering practice, the retrofit procedure is provided in a step-by step flowchart fashion.

Research papers, University of Canterbury Library

Liquefaction during the 4th September 2010 Mw 7.1 Darfield earthquake and large aftershocks in 2011 (Canterbury earthquake sequence, CES) caused severe damage to land and infrastructure within Christchurch, New Zealand. Approximately one third of the total CES-induced financial losses were directly attributable to liq- uefaction and thus highlights the need for local and regional authorities to assess liquefaction hazards for present and future developments. This thesis is the first to conduct paleo-liquefaction studies in eastern Christchurch for the purpose of de- termining approximate return times of liquefaction-inducing earthquakes within the region. The research uncovered evidence for pre-CES liquefaction dated by radiocarbon and cross-cutting relationships as post-1660 to pre-1905. Additional paleo-liquefaction investigations within the eastern Christchurch suburb of Avon- dale, and the northern township of Kaiapoi, revealed further evidence for pre-CES liquefaction. Pre-CES liquefaction in Avondale is dated as post-1321 and pre-1901, while the Kaiapoi features likely formed during three distinct episodes: post-1458 and possibly during the 1901 Cheviot earthquake, post-1297 to pre-1901, and pre-1458. Evaluation of the liquefaction potential of active faults within the Can- terbury region indicates that many faults have the potential to cause widespread liquefaction within Avondale and Kaiapoi. The identification of pre-CES liquefac- tion confirms that these areas have previously liquefied, and indicates that residen- tial development in eastern Christchurch between 1860 and 2005 occurred in areas containing geologic evidence for pre-CES liquefaction. Additionally, on the basis of detailed field and GIS-based mapping and geospatial-statistical analysis, the distribution and severity of liquefaction and lateral spreading within the eastern Christchurch suburb of Avonside is shown in this study to be strongly in uenced by geomorphic and topographic variability. This variability is not currently ac- counted for in site-specific liquefaction assessments nor the simplified horizontal displacement models, and accounts for some of the variability between the pre- dicted horizontal displacements and those observed during the CES. This thesis highlights the potential applications of paleo-liquefaction investigations and ge- omorphic mapping to seismic and liquefaction hazard assessments and may aid future land-use planning decisions.

Images, Alexander Turnbull Library

The cartoon shows Christchurch obscured by ash. Text reads 'Christchurch recovery package' and below are the words 'Cash cloud'. Context - Beginning on the 6th of June the Puyehue-Cordon Caulle volcano has been erupting for more than a week. Drifting ash clouds have been interupting flights. On Thursday 23 June Prime Minister John Key, Canterbury Earthquake Recovery Minister Gerry Brownlee and representatives from engineering consultants Tonkin & Taylor announced the first part of the Government's long-awaited land report that revealed the fate of up to 5000 quake-damaged homes. These homes were in the 'red zone'. But 10,500 owners in the orange zone were left in limbo, with their properties requiring further assessment. One of the options presented to residents in the red zone, ideal for people with replacement policies, was the government bought your land, and you dealt directly with your insurers about your house. However they got a shock when insurers told them they won't replace their homes, they'll only repair them, even though they're earmarked for certain demolition. Quantity: 1 digital cartoon(s).

Research papers, The University of Auckland Library

Unreinforced masonry (URM) is a construction type that was commonly adopted in New Zealand between the 1880s and 1930s. URM construction is evidently vulnerable to high magnitude earthquakes, with the most recent New Zealand example being the 22 February 2011 Mw6.3 Christchurch earthquake. This earthquake caused significant damage to a majority of URM buildings in the Canterbury area and resulted in 185 fatalities. Many URM buildings still exist in various parts of New Zealand today, and due to their likely poor seismic performance, earthquake assessment and retrofit of the remaining URM building stock is necessary as these buildings have significant architectural heritage and occupy a significant proportion of the nation’s building stock. A collaborative research programme between the University of Auckland and Reid Construction Systems was conducted to investigate an economical yet effective solution for retrofitting New Zealand’s existing URM building stock. This solution adopts the shotcrete technique using an Engineered Cementitious Composite (ECC), which is a polyvinyl alcohol fibre reinforced mortar that exhibits strain hardening characteristics. Collaborations have been formed with a number of consulting structural engineers throughout New Zealand to develop innovative and cost effective retrofit solutions for a number of buildings. Two such case studies are presented in this paper. http://www.concrete2013.com.au/technical-program/

Research papers, University of Canterbury Library

A seismic financial risk analysis of typical New Zealand reinforced concrete buildings constructed with topped precast concrete hollow-core units is performed on the basis of experimental research undertaken at the University of Canterbury over the last five years. An extensive study that examines seismic demands on a variety of multi-storey RC buildings is described and supplemented by the experimental results to determine the inter-storey drift capacities of the buildings. Results of a full-scale precast concrete super-assemblage constructed and tested in the laboratory in two stages are used. The first stage investigates existing construction and demonstrates major shortcomings in construction practice that would lead to very poor seismic performance. The second stage examines the performance of the details provided by Amendment No. 3 to the New Zealand Concrete Design Code NZS 3101:1995. This paper uses a probabilistic financial risk assessment framework to estimate the expected annual loss (EAL) from previously developed fragility curves of RC buildings with precast hollow core floors connected to the frames according to the pre-2004 standard and the two connection details recommended in the 2004 amendment. Risks posed by different levels of damage and by earthquakes of different frequencies are examined. The structural performance and financial implications of the three different connection details are compared. The study shows that the improved connection details recommended in the 2004 amendment give a significant economic payback in terms of drastically reduced financial risk, which is also representative of smaller maintenance cost and cheaper insurance premiums.

Research papers, University of Canterbury Library

Seismic behaviour of typical unreinforced masonry (URM) brick houses, that were common in early last century in New Zealand and still common in many developing countries, is experimentally investigated at University of Canterbury, New Zealand in this research. A one halfscale model URM house is constructed and tested under earthquake ground motions on a shaking table. The model structure with aspect ratio of 1.5:1 in plan was initially tested in the longitudinal direction for several earthquakes with peak ground acceleration (PGA) up to 0.5g. Toppling of end gables (above the eaves line) and minor to moderate cracking around window and door piers was observed in this phase. The structure was then rotated 90º and tested in the transverse (short) direction for ground motions with PGA up to 0.8g. Partial out-of-plane failure of the face loaded walls in the second storey and global rocking of the model was observed in this phase. A finite element analysis and a mechanism analysis are conducted to assess the dynamic properties and lateral strength of the model house. Seismic fragility function of URM houses is developed based on the experimental results. Damping at different phases of the response is estimated using an amplitude dependent equivalent viscous damping model. Financial risk of similar URM houses is then estimated in term of expected annual loss (EAL) following a probabilistic financial risk assessment framework. Risks posed by different levels of damage and by earthquakes of different frequencies are then examined.

Research papers, University of Canterbury Library

Peri-urban environments are critical to the connections between urban and rural ecosystems and their respective communities. Lowland floodplains are important examples that are attractive for urbanisation and often associated with the loss of rural lands and resources. In Christchurch, New Zealand, damage from major earthquakes led to the large-scale abandonment of urban residential properties in former floodplain areas creating a rare opportunity to re-imagine the future of these lands. This has posed a unique governance challenge involving the reassessment of land-use options and a renewed focus on disaster risk and climate change adaptation. Urban-rural tensions have emerged through decisions on relocating residential development, alternative proposals for land uses, and an unprecedented opportunity for redress of degraded traditional values for indigenous (Māori) people. Immediately following the earthquakes, existing statutory arrangements applied to many recovery needs and identified institutional responsibilities. Bespoke legislation was also created to address the scale of impacts. Characteristics of the approach have included attention to information acquisition, iterative assessment of land - use options, and a wide variety of opportunities for community participation. Challenges have included a protracted decision-making process with accompanying transaction costs, and a high requirement for coordination. The case typifies the challenges of achieving ecosystem governance where both urban and rural stakeholders have strong desires and an opportunity to exert influence. It presents a unique context for applying the latest thinking on ecosystem management, adaptation, and resilience, and offers transferable learning for the governance of peri-urban floodplains worldwide.