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Research papers, University of Canterbury Library

In recent years, significant research has been undertaken into the development of lead-extrusion damping technology. The high force-to-volume (HF2V) devices developed at the University of Canterbury have been the subject of much of this research. However, while these devices have undergone a limited range of velocity testing, limitations in test equipment has meant that they have never been tested at representative earthquake velocities. Such testing is important as the peak resistive force provided by the dampers under large velocity spikes is an important design input that must be known for structural applications. This manuscript presents the high-speed testing of HF2V devices with quasi-static force capacities of 250-300kN. These devices have been subjected to peak input velocities of approximately 200mm/s, producing peak resistive forces of approximately 350kN. The devices show stable hysteretic performance, with slight force reduction during high-speed testing due to heat build-up and softening of the lead working material. This force reduction is recovered following cyclic loading as heat is dissipated and the lead hardens again. The devices are shown to be only weakly velocity dependent, an advantage in that they do not deliver large forces to the connecting elements and surrounding structure if larger than expected response velocities occur. This high-speed testing is an important step towards uptake as it provides important information to designers.

Research papers, University of Canterbury Library

The recent Canterbury earthquake sequence in 2010-2011 highlighted a uniquely severe level of structural damage to modern buildings, while confirming the high vulnerability and life threatening of unreinforced masonry and inadequately detailed reinforced concrete buildings. Although the level of damage of most buildings met the expected life-safety and collapse prevention criteria, the structural damage to those building was beyond economic repair. The difficulty in the post-event assessment of a concrete or steel structure and the uneconomical repairing costs are the big drivers of the adoption of low damage design. Among several low-damage technologies, post-tensioned rocking systems were developed in the 1990s with applications to precast concrete members and later extended to structural steel members. More recently the technology was extended to timber buildings (Pres-Lam system). This doctoral dissertation focuses on the experimental investigation and analytical and numerical prediction of the lateral load response of dissipative post-tensioned rocking timber wall systems. The first experimental stages of this research consisted of component testing on both external replaceable devices and internal bars. The component testing was aimed to further investigate the response of these devices and to provide significant design parameters. Post-tensioned wall subassembly testing was then carried out. Firstly, quasi-static cyclic testing of two-thirds scale post-tensioned single wall specimens with several reinforcement layouts was carried out. Then, an alternative wall configuration to limit displacement incompatibilities in the diaphragm was developed and tested. The system consisted of a Column-Wall-Column configuration, where the boundary columns can provide the support to the diaphragm with minimal uplifting and also provide dissipation through the coupling to the post-tensioned wall panel with dissipation devices. Both single wall and column-wall-column specimens were subjected to drifts up to 2% showing excellent performance, limiting the damage to the dissipating devices. One of the objectives of the experimental program was to assess the influence of construction detailing, and the dissipater connection in particular proved to have a significant influence on the wall’s response. The experimental programs on dissipaters and wall subassemblies provided exhaustive data for the validation and refinement of current analytical and numerical models. The current moment-rotation iterative procedure was refined accounting for detailed response parameters identified in the initial experimental stage. The refined analytical model proved capable of fitting the experimental result with good accuracy. A further stage in this research was the validation and refinement of numerical modelling approaches, which consisted in rotational spring and multi-spring models. Both the modelling approaches were calibrated versus the experimental results on post-tensioned walls subassemblies. In particular, the multi-spring model was further refined and implemented in OpenSEES to account for the full range of behavioural aspects of the systems. The multi-spring model was used in the final part of the dissertation to validate and refine current lateral force design procedures. Firstly, seismic performance factors in accordance to a Force-Based Design procedure were developed in accordance to the FEMA P-695 procedure through extensive numerical analyses. This procedure aims to determine the seismic reduction factor and over-strength factor accounting for the collapse probability of the building. The outcomes of this numerical analysis were also extended to other significant design codes. Alternatively, Displacement-Based Design can be used for the determination of the lateral load demand on a post-tensioned multi-storey timber building. The current DBD procedure was used for the development of a further numerical analysis which aimed to validate the procedure and identify the necessary refinements. It was concluded that the analytical and numerical models developed throughout this dissertation provided comprehensive and accurate tools for the determination of the lateral load response of post-tensioned wall systems, also allowing the provision of design parameters in accordance to the current standards and lateral force design procedures.

Research papers, University of Canterbury Library

Sewerage systems convey sewage, or wastewater, from residential or commercial buildings through complex reticulation networks to treatment plants. During seismic events both transient ground motion and permanent ground deformation can induce physical damage to sewerage system components, limiting or impeding the operability of the whole system. The malfunction of municipal sewerage systems can result in the pollution of nearby waterways through discharge of untreated sewage, pose a public health threat by preventing the use of appropriate sanitation facilities, and cause serious inconvenience for rescuers and residents. Christchurch, the second largest city in New Zealand, was seriously affected by the Canterbury Earthquake Sequence (CES) in 2010-2011. The CES imposed widespread damage to the Christchurch sewerage system (CSS), causing a significant loss of functionality and serviceability to the system. The Christchurch City Council (CCC) relied heavily on temporary sewerage services for several months following the CES. The temporary services were supported by use of chemical and portable toilets to supplement the damaged wastewater system. The rebuild delivery agency -Stronger Christchurch Infrastructure Rebuild Team (SCIRT) was created to be responsible for repair of 85 % of the damaged horizontal infrastructure (i.e., water, wastewater, stormwater systems, and roads) in Christchurch. Numerous initiatives to create platforms/tools aiming to, on the one hand, support the understanding, management and mitigation of seismic risk for infrastructure prior to disasters, and on the other hand, to support the decision-making for post-disaster reconstruction and recovery, have been promoted worldwide. Despite this, the CES in New Zealand highlighted that none of the existing platforms/tools are either accessible and/or readable or usable by emergency managers and decision makers for restoring the CSS. Furthermore, the majority of existing tools have a sole focus on the engineering perspective, while the holistic process of formulating recovery decisions is based on system-wide approach, where a variety of factors in addition to technical considerations are involved. Lastly, there is a paucity of studies focused on the tools and frameworks for supporting decision-making specifically on sewerage system restoration after earthquakes. This thesis develops a decision support framework for sewerage pipe and system restoration after earthquakes, building on the experience and learning of the organisations involved in recovering the CSS following the CES in 2010-2011. The proposed decision support framework includes three modules: 1) Physical Damage Module (PDM); 2) Functional Impact Module (FIM); 3) Pipeline Restoration Module (PRM). The PDM provides seismic fragility matrices and functions for sewer gravity and pressure pipelines for predicting earthquake-induced physical damage, categorised by pipe materials and liquefaction zones. The FIM demonstrates a set of performance indicators that are categorised in five domains: structural, hydraulic, environmental, social and economic domains. These performance indicators are used to assess loss of wastewater system service and the induced functional impacts in three different phases: emergency response, short-term recovery and long-term restoration. Based on the knowledge of the physical and functional status-quo of the sewerage systems post-earthquake captured through the PDM and FIM, the PRM estimates restoration time of sewer networks by use of restoration models developed using a Random Forest technique and graphically represented in terms of restoration curves. The development of a decision support framework for sewer recovery after earthquakes enables decision makers to assess physical damage, evaluate functional impacts relating to hydraulic, environmental, structural, economic and social contexts, and to predict restoration time of sewerage systems. Furthermore, the decision support framework can be potentially employed to underpin system maintenance and upgrade by guiding system rehabilitation and to monitor system behaviours during business-as-usual time. In conjunction with expert judgement and best practices, this framework can be moreover applied to assist asset managers in targeting the inclusion of system resilience as part of asset maintenance programmes.

Audio, Radio New Zealand

DAVID SHEARER to the Prime Minister: Does he stand by all his statements? PAUL GOLDSMITH to the Minister of Finance: What reports has he received on the performance of the public service? Dr RUSSEL NORMAN to the Prime Minister: Does he stand by his statement about asset sales that it was the Governments intention that “every New Zealander who wants shares gets them”? SIMON O'CONNOR to the Minister for Tertiary Education, Skills and Employment: What progress has been made in expanding the Youth Guarantee Scheme to provide more 16 and 17 year-olds with fees-free tertiary training this year? Hon DAVID CUNLIFFE to the Minister for Economic Development: Does he stand by his statement that “the global financial crisis and the Canterbury earthquakes were not projected in any of those forecasts”? Rt Hon WINSTON PETERS to the Minister of Local Government: Has he been in communication with the Auckland Council over financial management issues, and if so, on what occasions this year? MIKE SABIN to the Minister for Social Development: How will the Government’s recently announced changes target young people not in education, employment or training? DENISE ROCHE to the Prime Minister: Does he stand by his comment that the Government has a “sinking lid policy” for pokie machines? Hon CLAYTON COSGROVE to the Minister of Finance: Does he stand by the statement made on his behalf in answer to Oral Question No 1 on 1 March 2012, that “I do know what is in the coalition agreement” and, if so, does he agree that the United Future-National confidence and supply agreement does not require United Future to vote for the Government’s asset sales legislation? TODD McCLAY to the Associate Minister of Conservation: What benefits will the Game Animal Council Bill bring for recreational hunters? Hon ANNETTE KING to the Minister of Housing: What response has he received to the “Smarter. Faster. Fairer” tenancy service which provides an 0800 phone customer service centre response to people with housing needs? JAMI-LEE ROSS to the Minister for ACC: What initiatives are underway to help raise awareness about falls in the home?  

Research papers, University of Canterbury Library

This paper describes part of an extensive experimental programme in progress at the University of Canterbury to develop Laminated Veneer Lumber (LVL) structural systems and connections for multistorey timber buildings in earthquake-prone areas. The higher mechanical properties of LVL, when compared to sawn timber, in addition to its low mass, flexibility of design and rapidity of construction, create the potential for increased use of LVL in multi-storey buildings. The development of these innovative ductile connections in LVL, proposed here for frame systems, have been based on the successful implementation of jointed ductile connections for precast concrete systems, started in the early 1990s with the PRESSS Program at the University of California, San Diego, further developed in Italy and currently under further refinement at the University of Canterbury. This paper investigates the seismic behaviour of the so-called “hybrid” connection, characterised by the combination of unbonded post-tensioned tendons and either external or internal energy dissipaters passing through the critical contact surface between the structural elements. Experimental results on hybrid exterior beam-to-column and column-to-foundation subassemblies under cyclic quasi-static unidirectional loading are presented. The proposed innovative solutions exhibit a very satisfactory seismic performance characterised by an appreciable energy dissipation capacity (provided by the dissipaters) combined with self-centring properties (provided by the unbonded tendons) and negligible damage of the LVL structural elements.

Research papers, University of Canterbury Library

Predicting building collapse due to seismic motion is critical in design and more so after a major event. Damaged structures can appear sound, but collapse under following major events. There can thus be significant risk in decision making after a major seismic event concerning the safe occupation of a building or surrounding areas, versus the unknown impact of unknown major aftershocks. Model-based pushover analyses are effective if the structural properties are well understood, which is not valid post-event when this risk information is most useful. This research combines Hysteresis Loop Analysis (HLA) structural health monitoring (SHM) and Incremental Dynamic Analysis (IDA) methods to determine collapse capacity and probability of collapse for a specific structure, at any time, a range of earthquake excitations to ensure robustness. The nonlinear dynamic analysis method presented enables constant updating of building performance predictions using post-event SHM results. The resulting combined methods provide near real-time updating of collapse fragility curves as events progress, quantifying the change of collapse probability or seismic induced losses for decision-making - a novel, higher resolution risk analysis than previously available. The methods are not computationally expensive and there is no requirement for a validated numerical model. Results show significant potential benefits and a clear evolution of risk. They also show clear need for extending SHM toward creating improved predictive models for analysis of subsequent events, where the Christchurch series of 2010-2011 had significant post-event aftershocks after each main event. Finally, the overall method is generalisable to any typical engineering demand parameter.

Research papers, University of Canterbury Library

Despite their good performance in terms of their design objectives, many modern code-prescriptive buildings built in Christchurch, New Zealand had to be razed after the 2010-2011 Canterbury earthquakes because repairs were deemed too costly due to widespread sacrificial damage. Clearly a more effective design paradigm is needed to create more resilient structures. Rocking, post-tensioned connections with supplemental energy dissipation can contribute to a damage avoidance designs (DAD). However, few have achieved all three key design objectives of damage-resistant rocking, inherent recentering ability, and repeatable, damage-free energy dissipation for all cycles, which together offer a response which is independent of loading history. Results of experimental tests are presented for a near full-scale rocking beam-column sub-assemblage. A matrix of test results is presented for the system under varying levels of posttensioning, with and without supplemental dampers. Importantly, this parametric study delineates each contribution to response. Practical limitations on posttensioning are identified: a minimum to ensure static structural re-centering, and a maximum to ensure deformability without threadbar yielding. Good agreement between a mechanistic model and experimental results over all parameters and inputs indicates the model is robust and accurate for design. The overall results indicate that it is possible to create a DAD connection where the non-linear force-deformation response is loading history independent and repeatable over numerous loading cycles, without damage, creating the opportunity for the design and implementation of highly resilient structures.

Research papers, University of Canterbury Library

Current seismic retrofit strategies generally focus on increasing the strength/stiffness or upgrading the mechanical properties of a structure or element. A typical drawback of this approach is that the demand on structural and sub-structural elements can be increased. In a previous contribution by the authors (Ireland et al., 2006) a counter-intuitive but rational seismic retrofit strategy consisting of selective weakening techniques was proposed. In this paper results of experimental investigations performed on benchmark & selectively weakened structural walls at the University of Canterbury are discussed. The experimental investigations consisted of quasi-static uni-directional tests on two benchmark and two retrofitted cantilever wall specimens. The first benchmark wall specimen was detailed as typical of pre-1970’s construction practice. An equivalent wall was retrofitted using a selective weakening approach involving a horizontal cut at foundation level to allow for a controlled rocking response. The second benchmark specimen represented a more severe scenario where the inelastic behaviour was 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 was implemented. The experimental results confirmed the viability and efficiency of the proposed retrofit technique towards improving the performance of structural walls. Constructability issues and suggestions for practical implementation of the proposed retrofit solution are also discussed.

Research papers, University of Canterbury Library

This dissertation addresses several fundamental and applied aspects of ground motion selection for seismic response analyses. In particular, the following topics are addressed: the theory and application of ground motion selection for scenario earthquake ruptures; the consideration of causal parameter bounds in ground motion selection; ground motion selection in the near-fault region where directivity effect is significant; and methodologies for epistemic uncertainty consideration and propagation in the context of ground motion selection and seismic performance assessment. The paragraphs below outline each contribution in more detail. A scenario-based ground motion selection method is presented which considers the joint distribution of multiple intensity measure (IM) types based on the generalised conditional intensity measure (GCIM) methodology (Bradley, 2010b, 2012c). The ground motion selection algorithm is based on generating realisations of the considered IM distributions for a specific rupture scenario and then finding the prospective ground motions which best fit the realisations using an optimal amplitude scaling factor. In addition, using different rupture scenarios and site conditions, two important aspects of the GCIM methodology are scrutinised: (i) different weight vectors for the various IMs considered; and (ii) quantifying the importance of replicate selections for ensembles with different numbers of desired ground motions. As an application of the developed scenario-based ground motion selection method, ground motion ensembles are selected to represent several major earthquake scenarios in New Zealand that pose a significant seismic hazard, namely, Alpine, Hope and Porters Pass ruptures for Christchurch city; and Wellington, Ohariu, and Wairarapa ruptures for Wellington city. A rigorous basis is developed, and sensitivity analyses performed, for the consideration of bounds on causal parameters (e.g., magnitude, source-to-site distance, and site condition) for ground motion selection. The effect of causal parameter bound selection on both the number of available prospective ground motions from an initial empirical as-recorded database, and the statistical properties of IMs of selected ground motions are examined. It is also demonstrated that using causal parameter bounds is not a reliable approach to implicitly account for ground motion duration and cumulative effects when selection is based on only spectral acceleration (SA) ordinates. Specific causal parameter bounding criteria are recommended for general use as a ‘default’ bounding criterion with possible adjustments from the analyst based on problem-specific preferences. An approach is presented to consider the forward directivity effects in seismic hazard analysis, which does not separate the hazard calculations for pulse-like and non-pulse-like ground motions. Also, the ability of ground motion selection methods to appropriately select records containing forward directivity pulse motions in the near-fault region is examined. Particular attention is given to ground motion selection which is explicitly based on ground motion IMs, including SA, duration, and cumulative measures; rather than a focus on implicit parameters (i.e., distance, and pulse or non-pulse classifications) that are conventionally used to heuristically distinguish between the near-fault and far-field records. No ad hoc criteria, in terms of the number of directivity ground motions and their pulse periods, are enforced for selecting pulse-like records. Example applications are presented with different rupture characteristics, source-to-site geometry, and site conditions. It is advocated that the selection of ground motions in the near-fault region based on IM properties alone is preferred to that in which the proportion of pulse-like motions and their pulse periods are specified a priori as strict criteria for ground motion selection. Three methods are presented to propagate the effect of seismic hazard and ground motion selection epistemic uncertainties to seismic performance metrics. These methods differ in their level of rigor considered to propagate the epistemic uncertainty in the conditional distribution of IMs utilised in ground motion selection, selected ground motion ensembles, and the number of nonlinear response history analyses performed to obtain the distribution of engineering demand parameters. These methods are compared for an example site where it is observed that, for seismic demand levels below the collapse limit, epistemic uncertainty in ground motion selection is a smaller uncertainty contributor relative to the uncertainty in the seismic hazard itself. In contrast, uncertainty in ground motion selection process increases the uncertainty in the seismic demand hazard for near-collapse demand levels.

Research papers, University of Canterbury Library

Surface rupture of the previously unrecognised Greendale Fault extended west-east for ~30 km across alluvial plains west of Christchurch, New Zealand, during the Mw 7.1 Darfield (Canterbury) earthquake of September 2010. Surface rupture displacement was predominantly dextral strike-slip, averaging ~2.5 m, with maxima of ~5 m. Vertical displacement was generally less than 0.75 m. The surface rupture deformation zone ranged in width from ~30 to 300 m, and comprised discrete shears, localised bulges and, primarily, horizontal dextral flexure. About a dozen buildings, mainly single-storey houses and farm sheds, were affected by surface rupture, but none collapsed, largely because most of the buildings were relatively flexible and resilient timber-framed structures and also because deformation was distributed over a relatively wide zone. There were, however, notable differences in the respective performances of the buildings. Houses with only lightly-reinforced concrete slab foundations suffered moderate to severe structural and non-structural damage. Three other buildings performed more favourably: one had a robust concrete slab foundation, another had a shallow-seated pile foundation that isolated ground deformation from the superstructure, and the third had a structural system that enabled the house to tilt and rotate as a rigid body. Roads, power lines, underground pipes, and fences were also deformed by surface fault rupture and suffered damage commensurate with the type of feature, its orientation to the fault, and the amount, sense and width of surface rupture deformation.

Audio, Radio New Zealand

DAVID SHEARER to the Prime Minister: Does he stand by his statement "I am deeply concerned about every child in New Zealand who is in poverty"; if so, why has the number of children living in material hardship grown under his watch? TODD McCLAY to the Minister of Finance: What measures has the Government taken to support vulnerable New Zealanders through the aftermath of the domestic recession and global financial crisis? METIRIA TUREI to the Prime Minister: When he said "we don't want to see any New Zealand child suffer … children don't get to make choices, they're often the victim of circumstance" does that mean he will take tangible steps to ensure children don't suffer because of circumstances beyond their control? Rt Hon WINSTON PETERS to the Prime Minister: Does he have confidence in the Minister of Immigration? Hon DAVID PARKER to the Minister of Finance: Compared to 2012, does the Reserve Bank forecast the New Zealand dollar (as measured by the Trade Weighted Index) to strengthen or weaken in the next two years, and does he believe this will make New Zealand exporters more competitive or less competitive? DAVID BENNETT to the Minister for Economic Development: How is the Government encouraging the sustainable use of natural resources to support jobs and grow the economy? Hon MARYAN STREET to the Minister of Health: Is he satisfied with the state of children's health in New Zealand; if not, why not? COLIN KING to the Minister of Energy and Resources: What recent announcement has he made about Block Offer 2012? EUGENIE SAGE to the Minister for the Environment: Does she agree with the New Zealand Freshwater Sciences Society in relation to freshwater that "failure to act with decisiveness and urgency risks further environmental degradation and erosion of our international environmental reputation"; if not, why not? Hon LIANNE DALZIEL to the Minister for Building and Construction: How quickly will he respond to the building performance, assessment and construction recommendations of the Royal Commission of Inquiry into Building Failure caused by the Canterbury Earthquakes? NICKY WAGNER to the Minister for Building and Construction: What is the Government doing in response to the Canterbury Earthquakes Royal Commission's full report? CLARE CURRAN to the Prime Minister: Does he stand by all his statements?

Audio, Radio New Zealand

Hon DAVID CUNLIFFE to the Prime Minister: Does he have confidence that his Ministers are ethical and competent? DAVID BENNETT to the Minister of Finance: What reports has he received on building momentum in the New Zealand economy and how this is supporting jobs? METIRIA TUREI to the Prime Minister: Has he checked his files yet regarding whether Hon John Banks declared a potential conflict of interest in relation to the New Zealand International Convention Centre Bill while still a Minister; if so, was any conflict declared? Hon ANNETTE KING to the Minister of Health: Is he satisfied with the performance of Health Benefits Ltd; if so, why? NICKY WAGNER to the Minister for Canterbury Earthquake Recovery: What recent progress has been made on the anchor projects in the Christchurch Central recovery plan? ANDREW WILLIAMS to the Minister of Conservation: Has he received any reports on the environmental impact of seismic surveying in the New Zealand Exclusive Economic Zone? Hon MARYAN STREET to the Minister of State Services: Has he asked the State Services Commissioner for reports on recent failures of state sector agencies to carry out their functions according to the law; if not, why not? IAN McKELVIE to the Minister for Primary Industries: What progress can he report on boosting innovation in the primary sector through the Primary Growth Partnership? Hon DAMIEN O'CONNOR to the Minister for Primary Industries: What reports, if any, has he received on the state of the New Zealand kiwifruit industry? PAUL FOSTER-BELL to the Minister of Police: What recent announcements has she made to support the victims of serious financial crime? Hon RUTH DYSON to the Minister of Conservation: Why did he tell the House on 24 September "the first I knew of the issue of the submission was just 5 days before" when as he stated on 17 October "The first full briefing on Tukituki was on 5 March and it confirmed the department's role in the process and mentioned nitrogen and phosphorous management"? Dr KENNEDY GRAHAM to the Minister for Climate Change Issues: Will he explain, given the latest projection of New Zealand's net greenhouse gas emissions is around 90 million tonnes in 2040, how the Government can conceivably reach its own emissions reduction target of 30 million tonnes by 2050?

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

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Prediction of building collapse due to significant seismic motion is a principle objective of earthquake engineers, particularly after a major seismic event when the structure is damaged and decisions may need to be made rapidly concerning the safe occupation of a building or surrounding areas. Traditional model-based pushover analyses are effective, but only if the structural properties are well understood, which is not the case after an event when that information is most useful. This paper combines hysteresis loop analysis (HLA) structural health monitoring (SHM) and incremental dynamic analysis (IDA) methods to identify and then analyse collapse capacity and the probability of collapse for a specific structure, at any time, a range of earthquake excitations to ensure robustness. This nonlinear dynamic analysis enables constant updating of building performance predictions following a given and subsequent earthquake events, which can result in difficult to identify deterioration of structural components and their resulting capacity, all of which is far more difficult using static pushover analysis. The combined methods and analysis provide near real-time updating of the collapse fragility curves as events progress, thus quantifying the change of collapse probability or seismic induced losses very soon after an earthquake for decision-making. Thus, this combination of methods enables a novel, higher-resolution analysis of risk that was not previously available. The methods are not computationally expensive and there is no requirement for a validated numerical model, thus providing a relatively simpler means of assessing collapse probability immediately post-event when such speed can provide better information for critical decision-making. Finally, the results also show a clear need to extend the area of SHM toward creating improved predictive models for analysis of subsequent events, where the Christchurch series of 2010–2011 had significant post-event aftershocks.

Audio, Radio New Zealand

Questions to Ministers 1. AARON GILMORE to the Minister of Finance: What steps are the Government and the Earthquake Commission taking to streamline the Canterbury earthquake claims process? 2. Hon PHIL GOFF to the Prime Minister: Does he stand by his statement that "the vast majority" of people will be "better off" as a result of his tax switch on 1 October 2010? 3. KEVIN HAGUE to the Minister of Conservation: Does she agree with Forest and Bird that "many endangered species will meet a watery death, or be rudely shunted from their homes", if the Mōkihinui dam is given the green light? 4. Hon ANNETTE KING to the Minister for ACC: Is he satisfied with the performance of ACC? 5. NICKY WAGNER to the Minister for Economic Development: What steps will the Government take to aid the recovery of the Canterbury region from the recent major earthquake? 6. Hon DAVID CUNLIFFE to the Minister of Finance: What advice, if any, did Treasury receive from KordaMentha in relation to South Canterbury Finance's financial condition prior to approving the extension of the Crown Retail Deposit Guarantee Scheme, and did this advice question whether such an extension was appropriate? 7. COLIN KING to the Minister of Transport: What is the Government doing to address challenges in delivering supplies into the area affected by the Canterbury earthquake? 8. Hon RUTH DYSON to the Minister of Health: When will all the District Health Board Annual Plans for 2010/11 be publicly available? 9. JO GOODHEW to the Minister of Education: How were Canterbury schools affected by last Saturday's earthquake, and what is the current situation for schools in the region? 10. Hon DAVID PARKER to the Attorney-General: Is his objective under the new foreshore and seabed bill to settle the protracted controversy around foreshore and seabed? 11. AMY ADAMS to the Minister of Agriculture: What is the Government doing to support the rural Canterbury community through the earthquake recovery? 12. DARIEN FENTON to the Minister of Labour: Does she stand by all of the statements made on her behalf in response to question for oral answer No. 11 on 9 September 2010? Questions to Members 1. DARIEN FENTON to the Chairperson of the Transport and Industrial Relations Committee: How many submissions were received on the Employment Relations Amendment Bill (No. 2) as at 5pm Monday, 13 September 2010?

Research papers, University of Canterbury Library

On Tuesday 22 February 2011, a 6.3 magnitude earthquake struck Christchurch, New Zealand’s second largest city. The ‘earthquake’ was in fact an aftershock to an earlier 7.1 magnitude earthquake that had occurred on Saturday 4 September 2010. There were a number of key differences between the two events that meant they had dramatically different results for Christchurch and its inhabitants. The 22 February 2011 event resulted in one of New Zealand’s worst natural disasters on record, with 185 fatalities occurring and hundreds more being injured. In addition, a large number of buildings either collapsed or were damaged to the point where they needed to be totally demolished. Since the initial earthquake in September 2010, a large amount of building-related research has been initiated in New Zealand to investigate the impact of the series of seismic events – the major focus of these research projects has been on seismic, structural and geotechnical engineering matters. One project, however, conducted jointly by the University of Canterbury, the Fire Protection Association of New Zealand and BRANZ, has focused on the performance of fire protection systems in the earthquakes and the effectiveness of the systems in the event of post-earthquake fires occurring. Fortunately, very few fires actually broke out following the series of earthquake events in Christchurch, but fire after earthquakes still has significant implications for the built environment in New Zealand, and the collaborative research has provided some invaluable insight into the potential threat posed by post-earthquake fires in buildings. As well as summarising the damage caused to fire protection systems, this paper discusses the flow-on effect for designing structures to withstand post-earthquake fires. One of the underlying issues that will be explored is the existing regulatory framework in New Zealand whereby structural earthquake design and structural design for fire are treated as discrete design scenarios.

Research papers, University of Canterbury Library

The recent earthquakes in Christchurch have made it clear that issues exist with current RC frame design in New Zealand. In particular, beam elongation in RC frame buildings was widespread and resulted in numerous buildings being rendered irreparable. Design solutions to overcome this problem are clearly needed, and the slotted beam is one such solution. This system has a distinct advantage over other damage avoidance design systems in that it can be constructed using current industry techniques and conventional reinforcing steel. As the name suggests, the slotted beam incorporates a vertical slot along part of the beam depth at the beam-column interface. Geometric beam elongation is accommodated via opening and closing of these slots during seismically induced rotations, while the top concrete hinge is heavily reinforced to prevent material inelastic elongation. Past research on slotted beams has shown that the bond demand on the bottom longitudinal reinforcement is increased compared with equivalent monolithic systems. Satisfying this increased bond demand through conventional means may yield impractical and economically less viable column dimensions. The same research also indicated that the joint shear mechanism was different to that observed within monolithic joints and that additional horizontal reinforcement was required as a result. Through a combination of theoretical investigation, forensic analysis, and database study, this research addresses the above issues and develops design guidelines. The use of supplementary vertical joint stirrups was investigated as a means of improving bond performance without the need for non-standard reinforcing steel or other hardware. These design guidelines were then validated experimentally with the testing of two 80% scale beam-column sub-assemblies. The revised provisions for bond within the bottom longitudinal reinforcement were found to be adequate while the top longitudinal reinforcement remained nominally elastic throughout both tests. An alternate mechanism was found to govern joint shear behaviour, removing the need for additional horizontal joint reinforcement. Current NZS3101:2006 joint shear reinforcement provisions were found to be more than adequate given the typically larger column depths required rendering the strut mechanism more effective. The test results were then used to further refine design recommendations for practicing engineers. Finally, conclusions and future research requirements were outlined.

Research papers, University of Canterbury Library

On 14 November 2016, the Mw 7.8 Kaikōura earthquake caused widespread damage along the east coast of the South Island, New Zealand. Kaikōura town itself was isolated from the rest of the country by landslides blocking off major roads. While impacts from the Kaikōura earthquake on large, urban population centres have been generally well documented, this thesis aims to fill gaps in academic knowledge regarding small rural towns. This thesis investigates what, where and when critical infrastructure and lifeline service disruption occurred following the 2016 Kaikōura earthquake in a selection of small towns, and how the communities in these areas adapted to disruption. Following a robust review of literature and news media, four small rural towns were selected from North Canterbury (Culverden & Waiau) and Marlborough (Seddon & Ward) in the South Island, New Zealand. Semi-structured interview sessions with a special focus on these towns were held with infrastructure managers, emergency response and recovery officials, and organisation leaders with experience or expertise in the 2016 Kaikōura earthquake. Findings were supplemented with emergency management situation reports to produce hazard maps and infrastructure exposure maps. A more detailed analysis was conducted for Waiau involving interdependence analyses and a level of service timeline for select lifeline services. The earthquake impacted roads by blocking them with landslides, debris and surface rupture. Bridges where shaken off their abutments, breaking infrastructure links such as fibre landlines as they went. Water supplies and other forms of infrastructure relied heavily on the level of service of roads, as rough rural terrain left few alternatives. Adapting to an artificial loss of road service, some Waiau locals created their own detour around a road cordon in order to get home to family and farms. Performance of dwellings was tied to socioeconomic factors as much as proximity to the epicentre. Farmers who lost water access pulled out fences to allow stock to drink from rivers. Socioeconomic differences between farmland and township residents also contributed to resilience variations between the towns assessed in this study. Understanding how small rural towns respond and adapt to disaster allows emergency management officials and policy to be well informed and flexible with planning for multiple size classes of towns.

Research papers, Lincoln University

Prognostic modelling provides an efficient means to analyse the coastal environment and provide effective knowledge for long term urban planning. This paper outlines how the use of SWAN and Xbeach numerical models within the ESRI ArcGIS interface can simulate geomorphological evolution through hydrodynamic forcing for the Greater Christchurch coastal environment. This research followed the data integration techniques of Silva and Taborda (2012) and utilises their beach morphological modelling tool (BeachMM tool). The statutory requirements outlined in the New Zealand Coastal Policy Statement 2010 were examined to determine whether these requirements are currently being complied with when applying the recent sea level rise predictions by the Intergovernmental Panel on Climate Change (2013), and it would appear that it does not meet those requirements. This is because coastal hazard risk has not been thoroughly quantified by the installation of the Canterbury Earthquake Recovery Authority (CERA) residential red zone. However, the Christchurch City Council’s (CCC) flood management area does provide an extent to which managed coastal retreat is a real option. This research assessed the effectiveness of the prognostic models, forecasted a coastline for 100 years from now, and simulated the physical effects of extreme events such as storm surge given these future predictions. The results of this research suggest that progradation will continue to occur along the Christchurch foreshore due to the net sediment flux retaining an onshore direction and the current hydrodynamic activity not being strong enough to move sediment offshore. However, inundation during periods of storm surge poses a risk to human habitation on low lying areas around the Avon-Heathcote Estuary and the Brooklands lagoon similar to the CCC’s flood management area. There are complex interactions at the Waimakariri River mouth with very high rates of accretion and erosion within a small spatial scale due to the river discharge. There is domination of the marine environment over the river system determined by the lack of generation of a distinct river delta, and river channel has not formed within the intertidal zone clearly. The Avon-Heathcote ebb tidal delta aggrades on the innner fan and erodes on the outer fan due to wave domination. The BeachMM tool facilitates the role of spatial and temporal analysis effectively and the efficiency of that performance is determined by the computational operating system.

Research papers, University of Canterbury Library

This thesis addresses the topic of local bond behaviour in RC structures. The mechanism of bond refers to the composite action between deformed steel reinforcing bars and the surrounding concrete. Bond behaviour is an open research topic with a wide scope, particularly because bond it is such a fundamental concept to structural engineers. However, despite many bond-related research findings having wide applications, the primary contribution of this research is an experimental evaluation of the prominent features of local bond behaviour and the associated implications for the seismic performance of RC structures. The findings presented in this thesis attempt to address some structural engineering recommendations made by the Canterbury Earthquakes Royal Commission following the 2010-2011 Canterbury (New Zealand) earthquake sequence. A chapter of this thesis discusses the structural behaviour of flexure-dominated RC wall structures with an insufficient quantity of longitudinal reinforcement, among other in situ conditions, that causes material damage to predominantly occur at a single crack plane. In this particular case, the extent of concrete damage and bond deterioration adjacent to the crack plane will influence the ductility capacity that is effectively provided by the reinforcing steel. As a consequence of these in situ conditions, some lightly reinforced wall buildings in Christchurch lost their structural integrity due to brittle fracture of the longitudinal reinforcement. With these concerning post-earthquake observations in mind, there is the underlying intention that this thesis presents experimental evidence of bond behaviour that allows structural engineers to re-assess their confidence levels for the ability of lightly reinforced concrete structures to achieve the life-safety seismic performance objective the ultimate limit state. Three chapters of this thesis are devoted to the experimental work that was conducted as the main contribution of this research. Critical details of the experimental design, bond testing method and test programme are reported. The bond stress-slip relationship was studied through 75 bond pull-out tests. In order to measure the maximum local bond strength, all bond tests were carried out on deformed reinforcing bars that did not yield as the embedded bond length was relatively short. Bond test results have been presented in two separate chapters in which 48 monotonic bond tests and 27 cyclic bond tests are presented. Permutations of the experiments include the loading rate, cyclic loading history, concrete strength (25 to 70 MPa), concrete age, cover thickness, bar diameter (16 and 20 mm), embedded length, and position of the embedded bond region within the specimen (close or far away to the free surface). The parametric study showed that the concrete strength significantly influences the maximum bond strength and that it is reasonable to normalise the bond stress by the square-root of the concrete compressive strength, √(f'c). The generalised monotonic bond behaviour is described within. An important outcome of the research is that the measured bond strength and stiffness was higher than stated by the bond stress-slip relationship in the fib Model Code 2010. To account for these observed differences, an alternative model is proposed for the local monotonic bond stress-slip relationship. Cyclic bond tests showed a significant proportion of the total bond degradation occurs after the loading cycle in the peak bond strength range, which is when bond slip has exceeded 0.5 mm. Subsequent loading to constant slip values showed a linear relationship between the amount of bond strength degradation and the log of the number of cycles that were applied. To a greater extent, the cyclic bond deterioration depends on the bond slip range, regardless of whether the applied load cycling is half- or fully-reversed. The observed bond deterioration and hysteretic energy dissipated during cyclic loading was found to agree reasonably well between these cyclic tests with different loading protocols. The cyclic bond deterioration was also found to be reasonably consistent exponential damage models found in the literature. This research concluded that the deformed reinforcing bars used in NZ construction, embedded in moderate to high strength concrete, are able to develop high local bond stresses that are mobilised by a small amount of local bond slip. Although the relative rib geometry was not varied within this experimental programme, a general conclusion of this thesis is that deformed bars currently available in NZ have a relative rib bearing area that is comparatively higher than the test bars used in previous international research. From the parametric study it was found that the maximum monotonic bond strength is significant enhanced by dynamic loading rates. Experimental evidence of high bond strength and initial bond stiffness generally suggests that only a small amount of local bond slip that can occur when the deformed test bar was subjected to large tension forces. Minimal bond slip and bond damage limits the effective yielding length that is available for the reinforcing steel to distribute inelastic material strains. Consequently, the potential for brittle fracture of the reinforcement may be a more problematic and widespread issue than is apparent to structural engineers. This research has provided information that improve the reliability of engineering predictions (with respect to ductility capacity) of maximum crack widths and the extent of bond deterioration that might occur in RC structures during seismic actions.

Audio, Radio New Zealand

TE URUROA FLAVELL to the Minister of Justice: Is she satisfied with the Electoral Commission's engagement with whanau, hapū, iwi and marae around the 2013 Māori Electoral Option; if so, what advice has she received that would explain why halfway through the process there are only 5,000 new enrolments? DAVID SHEARER to the Prime Minister: On what date was he, his office or the Department of Prime Minister and Cabinet first informed that David Henry would not meet his deadline of the end of May as set out in the terms of reference for reporting back and what reason did Mr Henry provide for the delay? KATRINA SHANKS to the Minister of Finance: What do recent indicators show about the economy's performance this year and its outlook for the next three to four years? DAVID SHEARER to the Prime Minister: Has he received any information that shows foreign intelligence agencies are routinely collecting emails, other communication or location data on New Zealand citizens and residents while they are in New Zealand; if so, has the resulting information been passed on to the Government Communications Security Bureau? ALFRED NGARO to the Minister of Education: What recent announcement has she made about achievement against National Standards? METIRIA TUREI to the Minister for Economic Development: Will the Government sign the legal contract between it and SkyCity for the SkyCity Convention Centre this week; if not, when will it sign this agreement? JAMI-LEE ROSS to the Minister of Housing: What policy conclusions, if any, does the Government draw from Priced Out – How New Zealand Lost its Housing Affordability and how consistent are its findings with those of the 2012 Productivity Commission Report on housing affordability? Hon ANNETTE KING to the Minister of Health: Does he stand by all his statements on health; if not, why not? NICKY WAGNER to the Minister for Canterbury Earthquake Recovery: How will the Government support the redevelopment and repopulation of the Christchurch Central Business District following the Canterbury earthquakes? CHRIS HIPKINS to the Minister of Education: Is she confident that the National Standards data being released today gives an accurate picture of student progress; if not, why not? Rt Hon WINSTON PETERS to the Prime Minister: Did he discuss with David Henry the requirement for Mr Henry to see the full unedited electronic record connected with the Kitteridge report leak; if not, why not? JOHN HAYES to the Minister of Customs: What information has he received regarding the success of automated passenger processing systems at the border?

Audio, Radio New Zealand

Hon PHIL HEATLEY to the Minister of Finance: What reports has he received on the economy – and especially on further signs of economic momentum in the regions and among manufacturers? Dr RUSSEL NORMAN to the Minister of Finance: How much did the Government's share sales in Mighty River Power, Meridian, and Air New Zealand raise, given that the Supplement to the 2010 Investment Statement of the Government of New Zealand projected that those sales would raise $5.18 billion? Hon DAVID PARKER to the Minister for ACC: How much did ACC invest in Pike River Coal Limited and in New Zealand Oil and Gas Limited over the last eight years, and how much has it made or lost in total on its investment in each company, taking into account share purchases, subscriptions and sales, dividends, and current share prices? Rt Hon WINSTON PETERS to the Minister of Māori Affairs: Does he stand by his statement "I know Māori want to talk about the place of the Treaty of Waitangi in our constitution, and how our legal and political systems can reflect tikanga Māori."; if so, why? Hon SHANE JONES to the Associate Minister of Finance: Is he satisfied with his performance in regard to his delegations as Associate Minister of Finance? JONATHAN YOUNG to the Minister for Building and Construction: What reports has he received regarding the state of the building and construction sector? GARETH HUGHES to the Minister for the Environment: Did the Environmental Protection Authority assess the full version of Anadarko's Discharge Management Plan and Emergency Response Plan as part of its evaluation of the company's Environmental Impact Assessment for the Deepwater Taranaki Well; if not, why not? Hon CLAYTON COSGROVE to the Minister of Finance: When, if at all, did Cabinet approve the timing of the Air New Zealand sell-down and what directions did Cabinet give the shareholding Ministers? NICKY WAGNER to the Minister of Housing: What steps is the Government taking to rebuild Christchurch's housing stock damaged or destroyed by the earthquakes? Hon DAMIEN O'CONNOR to the Minister for Primary Industries: Does he stand by his statement "The opportunity, and challenge, for our meat producers now is to add value to different cuts of meat and continue to sell the New Zealand story"; if so, why? IAN McKELVIE to the Minister of Local Government: How is the Government improving councils' financial reporting? DARIEN FENTON to the Minister of Labour: Does he stand by his statement that "I am especially keen to hear what affected parties have to say on the Part 6A proposals in the Bill, and will carefully consider their submissions and the recommendations of the select committee"?

Research papers, University of Canterbury Library

Objective: The nature of disaster research makes it difficult to adequately measure the impact that significant events have on a population. Large, representative samples are required, ideally with comparable data collected before the event. When Christchurch, New Zealand, was struck by multiple, devastating earthquakes, there presented an opportunity to investigate the effects of dose-related quakes (none, one, two or three over a 9-month period) on the cognition of Canterbury’s elderly population through the New Zealand Brain Research Institute’s (NZBRI’s) cognitive screening study. The related effects of having a concomitant medical condition, sex, age and estimated- full scale IQ (Est-FSIQ) on cognition were also investigated. Method: 609 participants were tested on various neuropsychological tests and a self-rated dementia scale in a one hour interview at the NZBRI. Four groups were established, based on the number of major earthquakes experienced at the time of testing: “EQ-dose: None” (N = 51) had experienced no quakes; “EQ-dose: One” (N = 193) had experienced the initial quake in September 2010; “EQ-dose: Two” (N = 82) also experienced the most devastating February 2011 quake; and “EQ-dose: Three” (N = 265) also the June 2011 quake at testing. Results: Two neuropsychological variables of Trail A and the AD8 were impacted by an EQ-dose effect, while having a medical condition was associated with poorer function on the MoCA, Rey Copy and Recall, Trail A, and AD8. Having a major medical condition led to worse performance on the Rey Copy and Recall following the major February earthquake. Males performed significantly better on Trail A and Rey Planning, while females better on the MoCA. Older participants (>73) had significantly lower scores on the MoCA than younger participants (<74), while those with a higher Est-FSIQ (>111) had better scores on the MoCA and Rey Recall than participants with a lower Est-FSIQ. Finally, predicted variable analysis (based on calculated, sample-specific Z-scores) failed to find a significant earthquake effect when variables of age, sex and Est-FSIQ were controlled for, while there was a significant effect of medical condition on each measure. Conclusion: The current thesis provides evidence suggesting resilience amongst Canterbury’s elderly population in the face of the sequence of significant quakes that struck the region over a year from September 2010. By contrast, having a major medical condition was a ‘more significant life event’ in terms of impact on cognition in this group.

Research papers, The University of Auckland Library

Following the 2010/2011 Canterbury (New Zealand) earthquakes the seismic design of buildings with precast concrete panels has received significant attention. Although this form of construction generally performed adequately in Christchurch, there were a considerable number of precast concrete panel connection failures. This observation prompted a review of more than 4700 panel details to establish representative details used in both existing and new multi-storey and low rise industrial precast concrete buildings. The detailing and quantity of each reviewed connection type in the sampled data is reported, and advantages and potential deficiencies of each connection type are discussed. Following the Canterbury earthquakes, it was observed that brittle failure had occurred in some grouted metal duct connections used for precast concrete wall panels, resulting in recommendations for more robust detailing of this connection type. A set of experimental tests was subsequently performed to investigate the in-plane seismic behaviour of precast concrete wall panel connections. This testing comprised of seven reversed cyclic in-plane tests of fullscale precast concrete wall panels having wall-to-foundation grouted metal duct connections. Walls with existing connection detailing were found to perform adequately when carrying low axial loads, but performance was found to be less satisfactory as the axial load and wall panel length increased. The use of new recommended detailing was observed to prevent brittle connection response and to improve the robustness of the reinforcement splice. A parametric investigation was conducted using the finite element method to predict the failure mode of metal duct connections. From the results of the parametric study on metal duct connections it was identified that there were three possible failure modes, being reinforcement fracture, concrete spalling without metal duct pull out, and concrete spalling with metal duct pull-out. An alternative simple analytical method was proposed in order to determine the type of connection failure without using a time-consuming finite element method. Grouted sleeves inserts are an alternative connector that is widely used to connect wall panels to the foundations. The two full-scale wall panels were subjected to reversed cyclic in-plane demands until failure of either the connection or the wall panel. Wall panel failure was due to a combination of connection reinforcement pulling-out from the coupler and reinforcement fracture. In addition, non-embedded grouted sleeve tests filled with different quality of grout were conducted by subjecting these coupler assemblages to cyclic and monotonic forces

Research papers, University of Canterbury Library

Recent severe earthquakes, such as Christchurch earthquake series, worldwide have put emphasis on building resilience. In resilient systems, not only life is protected, but also undesirable economic effects of building repair or replacement are minimized following a severe earthquake. Friction connections are one way of providing structure resilience. These include the sliding hinge joint with asymmetric friction connections (SHJAFCs) in beam-to-column connections of the moment resisting steel frames (MRSFs), and the symmetric friction connections (SFCs) in braces of the braced frames. Experimental and numerical studies on components have been conducted internationally. However, actual building performance depends on the many interactions, occurring within a whole building system, which may be difficult to determine accurately by numerical modelling or testing of structural components alone. Dynamic inelastic testing of a full-scale multi-storey composite floor building with full range of non-structural elements (NSEs) has not yet been performed, so it is unclear if surprises are likely to occur in such a system. A 9 m tall three-storey configurable steel framed composite floor building incorporating friction-based connections is to be tested using two linked bi-directional shake tables at the International joint research Laboratory of Earthquake Engineering (ILEE) facilities, Shanghai, China. Beams and columns are designed to remain elastic during an earthquake event, with all non-linear behaviour occurring through stable sliding frictional behaviour, dissipating energy by SHJAFCs used in MRFs and SFCs in braced frames, with and without Belleville springs. Structural systems are configurable, allowing different moment and braced frame structural systems to be tested in two horizontal directions. In some cases, these systems interact with rocking frame or rocking column system in orthogonal directions subjected to unidirectional and bidirectional horizontal shaking. The structure is designed and detailed to undergo, at worst, minor damage under series of severe earthquakes. NSEs applied include precast-concrete panels, glass curtain walling, internal partitions, suspended ceilings, fire sprinkler piping as well as some other common contents. Some of the key design considerations are presented and discussed herein

Research papers, University of Canterbury Library

The Sendai Framework for Disaster Risk Reduction 2015-2030 finds that, despite progress in disaster risk reduction over the last decade “evidence indicates that exposure of persons and assets in all countries has increased faster than vulnerability has decreased, thus generating new risk and a steady rise in disaster losses” (p.4, UNISDR 2015). Fostering cooperation among relevant stakeholders and policy makers to “facilitate a science-policy interface for effective decisionmaking in disaster risk management” is required to achieve two priority areas for action, understanding disaster risk and enhancing disaster preparedness (p. 13, p. 23, UNISDR 2015). In other topic areas, the term science-policy interface is used interchangeably with the term boundary organisation. Both terms are usually used refer to systematic collaborative arrangements used to manage the intersection, or boundary, between science and policy domains, with the aim of facilitating the joint construction of knowledge to inform decision-making. Informed by complexity theory, and a constructivist focus on the functions and processes that minimize inevitable tensions between domains, this conceptual framework has become well established in fields where large complex issues have significant economic and political consequences, including environmental management, biodiversity, sustainable development, climate change and public health. To date, however, there has been little application of this framework in the disaster risk reduction field. In this doctoral project the boundary management framework informs an analysis of the research response to the 2010-2011 Canterbury Earthquake Sequence, focusing on the coordination role of New Zealand’s national Natural Hazards Research Platform. The project has two aims. It uses this framework to tell the nuanced story of the way this research coordination role evolved in response to both the complexity of the unfolding post-disaster environment, and to national policy and research developments. Lessons are drawn from this analysis for those planning and implementing arrangements across the science-policy boundary to manage research support for disaster risk reduction decision-making, particularly after disasters. The second aim is to use this case study to test the utility of the boundary management framework in the disaster risk reduction context. This requires that terminology and concepts are explained and translated in terms that make this analysis as accessible as possible across the disciplines, domains and sectors involved in disaster risk reduction. Key findings are that the focus on balance, both within organisations, and between organisations and domains, and the emphasis on systemic effects, patterns and trends, offer an effective and productive alternative to the more traditional focus on individual or organisational performance. Lessons are drawn concerning the application of this framework when planning and implementing boundary organisations in the hazard and disaster risk management context.

Research papers, University of Canterbury Library

In the last century, seismic design has undergone significant advancements. Starting from the initial concept of designing structures to perform elastically during an earthquake, the modern seismic design philosophy allows structures to respond to ground excitations in an inelastic manner, thereby allowing damage in earthquakes that are significantly less intense than the largest possible ground motion at the site of the structure. Current performance-based multi-objective seismic design methods aim to ensure life-safety in large and rare earthquakes, and to limit structural damage in frequent and moderate earthquakes. As a result, not many recently built buildings have collapsed and very few people have been killed in 21st century buildings even in large earthquakes. Nevertheless, the financial losses to the community arising from damage and downtime in these earthquakes have been unacceptably high (for example; reported to be in excess of 40 billion dollars in the recent Canterbury earthquakes). In the aftermath of the huge financial losses incurred in recent earthquakes, public has unabashedly shown their dissatisfaction over the seismic performance of the built infrastructure. As the current capacity design based seismic design approach relies on inelastic response (i.e. ductility) in pre-identified plastic hinges, it encourages structures to damage (and inadvertently to incur loss in the form of repair and downtime). It has now been widely accepted that while designing ductile structural systems according to the modern seismic design concept can largely ensure life-safety during earthquakes, this also causes buildings to undergo substantial damage (and significant financial loss) in moderate earthquakes. In a quest to match the seismic design objectives with public expectations, researchers are exploring how financial loss can be brought into the decision making process of seismic design. This has facilitated conceptual development of loss optimisation seismic design (LOSD), which involves estimating likely financial losses in design level earthquakes and comparing against acceptable levels of loss to make design decisions (Dhakal 2010a). Adoption of loss based approach in seismic design standards will be a big paradigm shift in earthquake engineering, but it is still a long term dream as the quantification of the interrelationships between earthquake intensity, engineering demand parameters, damage measures, and different forms of losses for different types of buildings (and more importantly the simplification of the interrelationship into design friendly forms) will require a long time. Dissecting the cost of modern buildings suggests that the structural components constitute only a minor portion of the total building cost (Taghavi and Miranda 2003). Moreover, recent research on seismic loss assessment has shown that the damage to non-structural elements and building contents contribute dominantly to the total building loss (Bradley et. al. 2009). In an earthquake, buildings can incur losses of three different forms (damage, downtime, and death/injury commonly referred as 3Ds); but all three forms of seismic loss can be expressed in terms of dollars. It is also obvious that the latter two loss forms (i.e. downtime and death/injury) are related to the extent of damage; which, in a building, will not just be constrained to the load bearing (i.e. structural) elements. As observed in recent earthquakes, even the secondary building components (such as ceilings, partitions, facades, windows parapets, chimneys, canopies) and contents can undergo substantial damage, which can lead to all three forms of loss (Dhakal 2010b). Hence, if financial losses are to be minimised during earthquakes, not only the structural systems, but also the non-structural elements (such as partitions, ceilings, glazing, windows etc.) should be designed for earthquake resistance, and valuable contents should be protected against damage during earthquakes. Several innovative building technologies have been (and are being) developed to reduce building damage during earthquakes (Buchanan et. al. 2011). Most of these developments are aimed at reducing damage to the buildings’ structural systems without due attention to their effects on non-structural systems and building contents. For example, the PRESSS system or Damage Avoidance Design concept aims to enable a building’s structural system to meet the required displacement demand by rocking without the structural elements having to deform inelastically; thereby avoiding damage to these elements. However, as this concept does not necessarily reduce the interstory drift or floor acceleration demands, the damage to non-structural elements and contents can still be high. Similarly, the concept of externally bracing/damping building frames reduces the drift demand (and consequently reduces the structural damage and drift sensitive non-structural damage). Nevertheless, the acceleration sensitive non-structural elements and contents will still be very vulnerable to damage as the floor accelerations are not reduced (arguably increased). Therefore, these concepts may not be able to substantially reduce the total financial losses in all types of buildings. Among the emerging building technologies, base isolation looks very promising as it seems to reduce both inter-storey drifts and floor accelerations, thereby reducing the damage to the structural/non-structural components of a building and its contents. Undoubtedly, a base isolated building will incur substantially reduced loss of all three forms (dollars, downtime, death/injury), even during severe earthquakes. However, base isolating a building or applying any other beneficial technology may incur additional initial costs. In order to provide incentives for builders/owners to adopt these loss-minimising technologies, real-estate and insurance industries will have to acknowledge the reduced risk posed by (and enhanced resilience of) such buildings in setting their rental/sale prices and insurance premiums.

Research papers, University of Canterbury Library

In major seismic events, a number of plan-asymmetric buildings which experienced element failure or structural collapse had twisted significantly about their vertical axis during the earthquake shaking. This twist, known as “building torsion”, results in greater demands on one side of a structure than on the other side. The Canterbury Earthquakes Royal Commission’s reports describe the response of a number of buildings in the February 2011 Christchurch earthquakes. As a result of the catastrophic collapse of one multi-storey building with significant torsional irregularity, and significant torsional effects also in other buildings, the Royal Commission recommended that further studies be undertaken to develop improved simple and effective guides to consider torsional effects in buildings which respond inelastically during earthquake shaking. Separately from this, as building owners, the government, and other stakeholders, are planning for possible earthquake scenarios, they need good estimates of the likely performance of both new and existing buildings. These estimates, often made using performance based earthquake engineering considerations and loss estimation techniques, inform decision making. Since all buildings may experience torsion to some extent, and torsional effects can influence demands on building structural and non-structural elements, it is crucial that demand estimates consider torsion. Building seismic response considering torsion can be evaluated with nonlinear time history analysis. However, such analysis involves significant computational effort, expertise and cost. Therefore, from an engineers’ point of view, simpler analysis methods, with reasonable accuracy, are beneficial. The consideration of torsion in simple analysis methods has been investigated by many researchers. However, many studies are theoretical without direct relevance to structural design/assessment. Some existing methods also have limited applicability, or they are difficult to use in routine design office practice. In addition, there has been no consensus about which method is best. As a result, there is a notable lack of recommendations in current building design codes for torsion of buildings that respond inelastically. There is a need for building torsion to be considered in yielding structures, and for simple guidance to be developed and adopted into building design standards. This study aims to undertaken to address this need for plan-asymmetric structures which are regular over their height. Time history analyses are first conducted to quantify the effects of building plan irregularity, that lead to torsional response, on the seismic response of building structures. Effects of some key structural and ground motion characteristics (e.g. hysteretic model, ground motion duration, etc.) are considered. Mass eccentricity is found to result in rather smaller torsional response compared to stiffness/strength eccentricity. Mass rotational inertia generally decreases the torsional response; however, the trend is not clearly defined for torsionally restrained systems (i.e. large &lambda;ty). Systems with EPP and bilinear models have close displacements and systems with Takeda, SINA, and flag-shaped models yield almost the same displacements. Damping has no specific effect on the torsional response for the single-storey systems with the unidirectional eccentricity and excitation. Displacements of the single-storey systems subject to long duration ground motion records are smaller than those for short duration records. A method to consider torsional response of ductile building structures under earthquake shaking is then developed based on structural dynamics for a wide range of structural systems and configurations, including those with low and high torsional restraint. The method is then simplified for use in engineering practice. A novel method is also proposed to simply account for the effects of strength eccentricity on response of highly inelastic systems. A comparison of the accuracy of some existing methods (including code-base equivalent static method and model response spectrum analysis method), and the proposed method, is conducted for single-storey structures. It is shown that the proposed method generally provides better accuracy over a wide range of parameters. In general, the equivalent static method is not adequate in capturing the torsional effects and the elastic modal response spectrum analysis method is generally adequate for some common parameters. Record-to-record variation in maximum displacement demand on the structures with different degrees of torsional response is considered in a simple way. Bidirectional torsional response is then considered. Bidirectional eccentricity and excitation has varying effects on the torsional response; however, it generally increases the weak and strong edges displacements. The proposed method is then generalized to consider the bidirectional torsion due to bidirectional stiffness/strength eccentricity and bidirectional seismic excitation. The method is shown to predict displacements conservatively; however, the conservatism decreases slightly for cases with bidirectional excitation compared to those subject to unidirectional excitation. In is shown that the roof displacement of multi-storey structures with torsional response can be predicted by considering the first mode of vibration. The method is then further generalized to estimate torsional effects on multi-storey structure displacement demands. The proposed procedure is tested multi-storey structures and shown to predict the displacements with a good accuracy and conservatively. For buildings which twist in plan during earthquake shaking, the effect of P-&Delta;&lambda; action is evaluated and recommendations for design are made. P-&Delta;&lambda; has more significant effects on systems with small post- yield stiffness. Therefore, system stability coefficient is shown not to be the best indicator of the importance of P-&Delta;&lambda; and it is recommended to use post-yield stiffness of system computed with allowance for P-&Delta;&lambda; effects. For systems with torsional response, the global system stability coefficient and post- yield stiffness ration do not reflect the significance of P-&Delta;&lambda; effects properly. Therefore, for torsional systems individual seismic force resisting systems should be considered. Accuracy of MRSA is investigated and it is found that the MRSA is not always conservative for estimating the centre of mass and strong edge displacements as well as displacements of ductile systems with strength eccentricity larger than stiffness eccentricity. Some modifications are proposed to get the MRSA yields a conservative estimation of displacement demands for all cases.

Research papers, University of Canterbury Library

According to TS 1170.5, designing a building to satisfy code-prescribed criteria (e.g., drift limit, member safety, P-Δ stability) at the ultimate limit state and relying on the inherent margins within the design code would lead to an acceptable mean annual frequency of collapse (λ꜀) in the range of 10−⁴ to 10−⁵. Modern performance objectives, such as λ꜀ and expected annual loss (EAL), are not explicitly considered. Although buckling-restrained braced frame (BRBF) buildings were widely adopted as lateral load-resisting systems for office and car park buildings in the Christchurch rebuild following the Canterbury earthquakes in New Zealand, there are currently no official guidelines for their design. The primary focus of this study is to develop a risk-targeted design framework for BRBF buildings that can achieve the performance objectives desired by stakeholders. To this extent, key factors influencing λ꜀ and EAL of BRBF buildings are identified. These factors include gusset plate design, number of storeys, design drift limit, BRBF beam-column connection, brace configuration, brace angle, brace material grade, and analysis method (equivalent lateral force vs. modal response spectrum). A novel 3D BRBF modelling approach capable of simulating out-of-plane buckling failure of buckling-restrained brace (BRB) gusset plates is developed. Prior experimental studies on sub-assemblies conducted elsewhere have demonstrated that gusset plates and end zones may buckle out of plane prematurely, before BRBs reach their maximum axial compression load carrying capacity. Current 2D BRBF macro models, typically used in research, cannot simulate this failure mode. A conventional 2D BRBF model underestimates the λ꜀ of a case-study 4-storey super-X configured steel BRBF building (designed according to NZS-3404) by a factor of two compared to the estimate from the proposed 3D model. These findings suggest that the current NZS-3404 gusset plate design method may undersize gusset plates and that using a 2D BRBF model in this case can significantly underestimate λ꜀. Three improved alternative gusset plate design methods that are easy to implement in practice are identified from the literature. Gusset plates in two case-study 4-storey steel BRBF buildings with super-X and diagonal configurations are designed using both the NZS-3404 method and alternative methods. All three alternative design methods are found to be conservative, resulting in an almost three-fold lower λ꜀ for both case-study BRBF buildings compared to those designed using the NZS-3404 method. Analysis results indicate that (i) bidirectional interaction has no significant effect on gusset plate buckling and (ii) mid-span gusset plates are more susceptible to buckling than corner gusset plates. A framework for seismic loss assessment using incremental dynamic analysis (IDA), called loss-oriented hazard-consistent incremental dynamic analysis (LOHC-IDA), is developed. IDA can be conducted with a generic record set, eliminating the arduous site-specific record selection required to conduct multiple stripe analysis (MSA). Traditional IDA, however, is limited in producing hazard-consistent estimates of engineering demand parameters (EDPs), which LOHC-IDA overcomes. LOHC-IDA improves upon existing methods by: (i) incorporating correlations among engineering demand parameters across intensity levels and (ii) using peak ground acceleration (PGA) to predict peak floor acceleration (PFA). For two case-study steel BRBF buildings, LOHC-IDA estimates the EAL and loss distributions conditioned on the intensity level that closely match the MSA results, with an average absolute error of 5%. The influence of factors beyond gusset plate design on the λ꜀ and EAL of 26 case-study steel BRBF buildings (designed in accordance with TS 1170.5) is examined. Hazard-consistent λ꜀ and EAL for these buildings are estimated using the FEMA P-58 loss and risk assessment framework. Among the 26 case-study buildings, 23 satisfy the maximum code-specified λ꜀ limit of 10−⁴. The EAL, normalised by the total building replacement cost, is highest for 2-storey BRBFs (0.22% on average), followed by 4-storey BRBFs (0.16% on average) and 8-storey BRBFs (0.11% on average). Reducing the design drift limit has the most significant effect on lowering λ꜀ (all BRBF designs were drift governed), followed by transitioning from pinned to moment-resisting beam-column connections, reducing the brace angle, and increasing brace strength. BRBF buildings designed using the equivalent lateral force method, on average, have a lower λ꜀ compared to those designed using the modal response spectrum method. Diagonally configured BRBFs exhibit the lowest λ꜀, followed by super- X and chevron configured BRBFs. Most design variables, apart from drift limit and beam-column connection, have limited influence on EAL. A simple method for EDP-targeted design of steel BRBF buildings is proposed. For this purpose, linear regression and CatBoost machine learning models are developed to predict steel BRBF building EDPs using peak storey drift ratio (PSDR) and PFA estimates from the 26 case-study buildings at intensity levels ranging from 80% to 0.5% probability of exceedance in 50 years. The R²ₐₔⱼ of these models is around 0.98, while the average prediction error is less than 10%. Fundamental period (T₁), total building height (Hₜ), and pseudospectral acceleration at T₁, denoted as Sₐ(T₁), are selected as the features to predict PSDR, while T₁, Hₜ, and PGA are the features selected to predict PFA. The EDP-targeted design has three steps: (i) for a given Hₜ value, the PSDR prediction model is used to identify a suitable T₁ that can achieve a desired PSDR target at the design intensity, (ii) a force-based design is then conducted iteratively to achieve the target T₁ by using an appropriate ductility factor and design drift limit, and (iii) based on the T₁ in the final design iteration, the PFA demand estimated by the PFA prediction models is used as a conservative input for the design of acceleration-sensitive non-structural elements. An equation to predict λ꜀ at the design stage is proposed for collapse risk-targeted seismic design of buildings. This equation comprises three principal components: reserve building strength, a proxy for effective structural stiffness, and reserve building deformation capacity. This equation is calibrated for the collapse risk-targeted design of BRBF buildings in New Zealand using results from 26 case-study BRBF buildings. The validity of this equation is demonstrated with three design verification examples designed to specific λ꜀ targets. Considering λ꜀ from hazard-consistent incremental dynamic analysis as the benchmark, the mean absolute percentage error in the design-stage prediction of λ꜀ of the verification buildings is approximately 10%.

Research papers, University of Canterbury Library

In recent years, rocking isolation has become an effective approach to improve seismic performance of steel and reinforced concrete structures. These systems can mitigate structural damage through rigid body displacement and thus relatively low requirements for structural ductility, which can significantly improve seismic resilience of structures and reduce repairing costs after strong earthquakes. A number of base rocking structural systems with only a single rocking interface have been proposed. However, these systems can have significant high mode effect for high rise structures due to the single rocking interface. This RObust BUilding SysTem (ROBUST) project is a collaborative China-New Zealand project sponsored by the International Joint Research Laboratory of Earthquake Engineering (ILEE), Tongji University, and a number of agencies and universities within New Zealand including the BRANZ, Comflor, Earthquake Commission, HERA, QuakeCoRE, QuakeCentre, University of Auckland, and the University of Canterbury. A number of structural configurations will be tested [1, 2], and non-structural elements including ceilings, infilling walls, glazed curtain walls, precast concrete panels, piping system will also be tested in this project [3]. Within this study, a multiple rocking column steel structural system was proposed and investigated mainly by Tongji team with assistance of NZ members. The concept of rocking column system initiates from the structure of Chinese ancient wooden pagoda. In some of Chinese wooden pagodas, there are continuous core columns hanged only at the top of each pagoda, which is not connected to each stories. This core column can effectively avoid collapse of the whole structure under large storey drifts. Likewise, there are also central continuous columns in the newly proposed steel rocking column system, which can avoid weak story failure mechanism and make story drifts more uniform. In the proposed rocking column system, the structure can switch between an elastic rigidly connected moment resisting frame and a controlled rocking column system when subjected to strong ground motion excitations. The main seismic energy can be dissipated by asymmetric friction beam–column connections, thereby effectively reducing residual displacement of the structure under seismic loading without causing excessive damage to structural members. Re–centering of the structure is provided not only by gravity load carried by rocking columns, but also by mould coil springs. To investigate dynamic properties of the proposed system under different levels of ground excitations, a full-scale threestory steel rocking column structural system with central continuous columns is to be tested using the International joint research Laboratory of Earthquake Engineering (ILEE) facilities, Shanghai, China and an analytical model is established. A finite element model is also developed using ABAQUS to simulate the structural dynamic responses. The rocking column system proposed in this paper is shown to produce resilient design with quick repair or replacement.