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Research Papers, Lincoln University

The 2013 Seddon earthquake (Mw 6.5), the 2013 Lake Grassmere earthquake (Mw 6.6), and the 2016 Kaikōura earthquake (Mw 7.8) provided an opportunity to assemble the most extensive damage database to wine storage tanks ever compiled worldwide. An overview of this damage database is presented herein based on the in-field post-earthquake damage data collected for 2058 wine storage tanks (1512 legged tanks and 546 flat-based tanks) following the 2013 earthquakes and 1401 wine storage tanks (599 legged tanks and 802 flat-based tanks) following the 2016 earthquake. Critique of the earthquake damage database revealed that in 2013, 39% and 47% of the flat-based wine tanks sustained damage to their base shells and anchors respectively, while due to resilience measures implemented following the 2013 earthquakes, in the 2016 earthquake the damage to tank base shells and tank anchors of flat-based wine tanks was reduced to 32% and 23% respectively and instead damage to tank barrels (54%) and tank cones (43%) was identified as the two most frequently occurring damage modes for this type of tank. Analysis of damage data for legged wine tanks revealed that the frame-legs of legged wine tanks sustained the greatest damage percentage among different parts of legged tanks in both the 2013 earthquakes (40%) and in the 2016 earthquake (44%). Analysis of damage data and socio-economic findings highlight the need for industry-wide standards, which may have socio-economic implications for wineries.

Research papers, University of Canterbury Library

Case study analysis of the 2010-2011 Canterbury Earthquake Sequence (CES), which particularly impacted Christchurch City, New Zealand, has highlighted the value of practical, standardised and coordinated post-earthquake geotechnical response guidelines for earthquake-induced landslides in urban areas. The 22nd February 2011 earthquake, the second largest magnitude event in the CES, initiated a series of rockfall, cliff collapse and loess failures around the Port Hills which severely impacted the south-eastern part of Christchurch. The extensive slope failure induced by the 22nd February 200 earthquake was unprecedented; and ground motions experienced significantly exceeded the probabilistic seismic hazard model for Canterbury. Earthquake-induced landslides initiated by the 22nd February 2011 earthquake posed risk to life safety, and caused widespread damage to dwellings and critical infrastructure. In the immediate aftermath of the 22nd February 2011 earthquake, the geotechnical community responded by deploying into the Port Hills to conduct assessment of slope failure hazards and life safety risk. Coordination within the voluntary geotechnical response group evolved rapidly within the first week post-earthquake. The lack of pre-event planning to guide coordinated geotechnical response hindered the execution of timely and transparent management of life safety risk from coseismic landslides in the initial week after the earthquake. Semi-structured interviews were conducted with municipal, management and operational organisations involved in the geotechnical response during the CES. Analysis of interview dialogue highlighted the temporal evolution of priorities and tasks during emergency response to coseismic slope failure, which was further developed into a phased conceptual model to inform future geotechnical response. Review of geotechnical responses to selected historical earthquakes (Northridge, 1994; Chi-Chi, 1999; Wenchuan, 2008) has enabled comparison between international practice and local response strategies, and has emphasised the value of pre-earthquake preparation, indicating the importance of integration of geotechnical response within national emergency management plans. Furthermore, analysis of the CES and international earthquakes has informed pragmatic recommendations for future response to coseismic slope failure. Recommendations for future response to earthquake-induced landslides presented in this thesis include: the integration of post-earthquake geotechnical response with national Civil Defence and Emergency Management; pre-earthquake development of an adaptive management structure and standard slope assessment format for geotechnical response; and emergency management training for geotechnical professionals. Post-earthquake response recommendations include the development of geographic sectors within the area impacted by coseismic slope failure, and the development of a GIS database for analysis and management of data collected during ground reconnaissance. Recommendations provided in this thesis aim to inform development of national guidelines for geotechnical response to earthquake-induced landslides in New Zealand, and prompt debate concerning international best practice.

Research papers, University of Canterbury Library

Very little research exists on total house seismic performance. This testing programme provides stiffness and response data for five houses of varying ages including contributions of non-structural elements. These light timber framed houses in Christchurch, New Zealand had minor earthquake damage from the 2011 earthquakes and were lateral load tested on site to determine their strength and stiffness, and preliminary damage thresholds. Dynamic characteristics were also investigated. Various loading schemes were utilised including quasi-static loading above the foundation, unidirectional loading through the floor diaphragm, cyclic quasi-static loading and snapback tests. Dynamic analysis on two houses provided the seismic safety levels of post-quake houses with respect to local hazard levels. Compared with New Zealand Building Standards all the tested houses had an excess of strength, damage is a significant consideration in earthquake resilience and was observed in all of the houses. A full size house laboratory test is proposed.

Audio, Radio New Zealand

A review of the week's news including: Christchurch's emergency operation moves from rescue to recovery, two minutes' silence observed nationwide, government announces aid package, Finance Minister outlines cost of quake, a fifth of Christchurch population has fled, inquiry launched into collapse of damaged buildings, many Christchurch schools remain closed and some of their pupils enrol elsewhere, students and farmers roll up their sleeves to help quake victims, rescuers tell stories of survival, hundreds of Wellington buildings expected not to meet earthquake safety standards and time capsule discovered under statue of Christchurch founding father

Research papers, The University of Auckland Library

There is very little research on total house strength that includes contributions of non-structural elements. This testing programme provides inclusive stiffness and response data for five houses of varying ages. These light timber framed houses in Christchurch, New Zealand had minor earthquake damage from the 2011 earthquakes and were lateral load tested on site to determine their strength and/or stiffness, and to identify damage thresholds. Dynamic characteristics including natural periods, which ranged from 0.14 to 0.29s were also investigated. Two houses were quasi-statically loaded up to approximately 130kN above the foundation in one direction. Another unidirectional test was undertaken on a slab-on-grade two-storey house, which was also snapback tested. Two other houses were tested using cyclic quasi-static loading, and between cycles snapback tests were undertaken to identify the natural period of each house, including foundation and damage effects. A more detailed dynamic analysis on one of the houses provided important information on seismic safety levels of post-quake houses with respect to different hazard levels in the Christchurch area. While compared to New Zealand Building Standards all tested houses had an excess of strength, damage is a significant consideration in earthquake resilience and was observed in all of the houses. http://www.aees.org.au/downloads/conference-papers/2015-2/

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.

Audio, Radio New Zealand

Questions to Ministers 1. JONATHAN YOUNG to the Minister of Finance: What advice has he received about factors that lie behind the current turmoil we are witnessing on world financial markets, and what are the implications for New Zealand? 2. KEVIN HAGUE to the Minister of Labour: Does she still agree, as she did on 13 July 2011, with the comment made by Rt Hon John Key on 22 November 2010 that "I have no reason to believe that New Zealand safety standards are any less than Australia's and in fact our safety record for the most part has been very good"? 3. Hon ANNETTE KING to the Prime Minister: Does he stand by his answers to Oral Question No 1 yesterday when he said that the Leader of the Opposition is "just plain wrong" in relation to skills training? 4. KATRINA SHANKS to the Minister for the Environment: How have Government reforms to the Resource Management Act helped increase competition in the grocery business? 5. Hon CLAYTON COSGROVE to the Attorney-General: Will he meet with earthquake victims' families to hear directly why they need independent legal representation; if not, why not? 6. Hon JOHN BOSCAWEN to the Minister of Finance: Does he stand by his statement that "I think the New Zealand Institute of Economic Research is referring to some longer-term issues around demographic change and healthcare costs, and we share the chief executive's concern"? 7. DARIEN FENTON to the Minister of Labour: What is the timeline of the ministerial inquiry into the treatment of foreign fishing crews in New Zealand waters? 8. CHRIS AUCHINVOLE to the Minister for Communications and Information Technology: What progress is being made on the Government's goal of delivering fast broadband to rural areas? 9. Dr KENNEDY GRAHAM to the Minister for Canterbury Earthquake Recovery: Does he agree that an appropriate part of the "red zone" area along the Avon River through Christchurch should be transformed into a "green space" for memorial and recreational public purposes? 10. STUART NASH to the Minister of Finance: Does he believe the tax system is fair for all New Zealanders? 11. KANWALJIT SINGH BAKSHI to the Minister for Social Development and Employment: What steps has the Government taken to manage gateways between benefits? 12. KELVIN DAVIS to the Minister of Education: Does she stand by all of her answers to Oral Question No 8 yesterday?

Audio, Radio New Zealand

DAVID SHEARER to the Prime Minister: Does he believe that Hon John Banks has behaved in a manner that “upholds, and is seen to uphold the highest ethical standards” as required by the Cabinet Manual? BARBARA STEWART to the Prime Minister: Did Mr Banks explain to the Prime Minister’s Chief of Staff that he would use “obfuscation” in his dealings with the media over the “anonymous” donations from Kim Dotcom? MAGGIE BARRY to the Minister of Finance: How does the Government intend to strengthen the Public Finance Act 1989 in the Budget this month? Hon DAVID PARKER to the Minister of Finance: In the most recent World Economic Outlook published by the IMF in April 2012, which of the 34 advanced economies listed is forecast to have a worse current account deficit (as a percentage of GDP) than New Zealand in 2013? METIRIA TUREI to the Prime Minister: Does he stand by all the answers he gave to Oral Question No 4 yesterday? KANWALJIT SINGH BAKSHI to the Minister for Economic Development: What action is the Government taking to improve co-ordination of the business growth agenda? Hon PHIL GOFF to the Minister of Foreign Affairs: What damage, if any, has been done to staff confidence and retention by the change proposals for his Ministry announced on 23 February 2012, and does he intend to announce on 10 May 2012 a reversal of many of the proposals? SIMON O'CONNOR to the Minister of Labour: What steps is the Government taking to improve workplace health and safety? GARETH HUGHES to the Minister of Conservation: Does her proposed extension of the Marine Mammal Sanctuary for Maui’s dolphins allow the use of set nets, drift nets, and trawl nets within the sanctuary? IAN McKELVIE to the Minister of Corrections: What reports has she received about trade training within prisons? Hon LIANNE DALZIEL to the Minister for Canterbury Earthquake Recovery: Has he required that all his Ministers involved in the Canterbury earthquake recovery read the briefing paper dated 10 May 2011 prepared by Chief Science Advisor, Professor Sir Peter Gluckman, into the psychosocial consequences of the Canterbury earthquakes; if not, why not? NIKKI KAYE to the Minister of Education: What evidence has she seen of excellent achievement in scholarship exams?  

Audio, Radio New Zealand

GRANT ROBERTSON to the Minister for Tertiary Education, Skills and Employment: Does he stand by his statement that the Household Labour Force Survey is "the standard internationally recognised measure of employment and unemployment"? PAUL GOLDSMITH to the Minister of Finance: What recent reports has he received on the economy? Dr KENNEDY GRAHAM to the Minister for Climate Change Issues: Does he stand by the answer given by the Minister of Finance to the question "Does he accept that human-induced climate change is real?" that "It may well be…"? Hon DAVID PARKER to the Minister of Finance: Given that unemployment is rising, exports are down, and house price inflation in Auckland and Canterbury is in double-digits, does he agree that after 5 years as Finance Minister he has failed to rebalance and diversify the economy; if not, why not? JOHN HAYES to the Minister of Trade: What efforts is the Government making to deal with the market effects of the possible contamination of some Fonterra diary exports? Hon SHANE JONES to the Minister for Economic Development: What action has he taken to ensure high value jobs are retained in Otago, Waikato, Northland, East Coast and Manawatu? KEVIN HAGUE to the Minister of Health: Exactly how many of the 21 recommendations to the Minister in the 2010 Public Health Advisory Committee Report The Best Start in Life: Achieving effective action on child health and wellbeing has he implemented? JACQUI DEAN to the Minister for Food Safety: What update can she provide the public on the safety of infant formula? Hon DAMIEN O'CONNOR to the Minister for Primary Industries: Does he stand by all his statements? NICKY WAGNER to the Minister for Building and Construction: What reports has he received following the Government's announcement of a new earthquake-prone building policy? RICHARD PROSSER to the Minister for Primary Industries: What reports, if any, has he received regarding the regeneration of fish stocks in the Snapper 1 fishery? Dr DAVID CLARK to the Minister for Economic Development: Does he agree with Dunedin Mayor Dave Cull that "Central government needs to understand we can't have a … two-speed economy where Christchurch and Auckland are ripping ahead and the rest of the regions are withering"; if not, why not?

Audio, Radio New Zealand

1. TODD McCLAY to the Minister of Finance: What reports has he received on the economy? 2. KEVIN HAGUE to the Minister of Labour: Does she agree that the test of practicability in the Health and Safety in Employment (Mining-Underground) Regulations 1999 is likely to result in different mines having different safety standards, in contrast to the regulations in place until 1992? 3. Hon ANNETTE KING to the Prime Minister: In light of his comment that "New Zealand is to be congratulated because, at least in terms of the gender pay gap, ours is the third lowest in the OECD", does that mean he is satisfied with the 10.6 percent gap between men's and women's pay in our country? 4. LOUISE UPSTON to the Minister for Social Development and Employment: What reports has she received on the latest benefit numbers? 5. Hon CLAYTON COSGROVE to the Minister for Canterbury Earthquake Recovery: Does he consider the allocation of the value of the land within the rating valuation process to be robust, when it has produced such variable outcomes, leaving many in the red zone with insufficient funds to buy a section to take advantage of the replacement option in their insurance policy? 6. Dr CAM CALDER to the Minister for the Environment: What work is his Ministry doing to help New Zealand take up the opportunity from green growth following the OECD May 2011 report on the high expected global demand for such products and services? 7. Hon MARYAN STREET to the Minister of Foreign Affairs: How many human resources contracts, if any, were let by the Ministry of Foreign Affairs and Trade without tenders being invited in 2010/2011, and what criteria were used to assess non-tendered contractors? 8. PAUL QUINN to the Minister of Transport: What is the Government doing to improve Wellington's commuter rail network? 9. METIRIA TUREI to the Prime Minister: Does he stand by his statement "there is no question in my mind - someone would be better off in paid employment than on welfare. If they were not, that is a real indictment on the welfare system"? 10. Hon TREVOR MALLARD to the Minister of Finance: When he said that "I did visit the Chinese Investment Corporation … They are very pleased with New Zealand's economic policy", was one of the policies he discussed with this foreign sovereign wealth fund his plan for privatising state assets? 11. JAMI-LEE ROSS to the Minister of Broadcasting: What recent announcements has the Government made on progress towards digital switchover? 12. GRANT ROBERTSON to the Minister of Health: Does he stand by his statement to the Cabinet Expenditure Control Committee that "we may need to take some tough choices regarding the scope and range of services the public health system can provide to New Zealanders"?

Audio, Radio New Zealand

DAVID BENNETT to the Minister of Finance: How is the Government's economic programme supporting stronger regional job growth? Hon SHANE JONES to the Minister of Commerce: Is he aware of demands being made by the Countdown supermarket group for retrospective payments from New Zealand suppliers, with threats Countdown will not stock their products? JULIE ANNE GENTER to the Minister for Economic Development: Why is the Government holding up economic development in Auckland's CBD, according to Auckland City officials, by delaying the opening of the City Rail Link until 2025? ALFRED NGARO to the Minister for Social Development: What reports has she received about the state of the nation in relation to social outcomes? DENIS O'ROURKE to the Minister for Canterbury Earthquake Recovery: Is he aware of any proposals to transport asbestos-contaminated material from the Christchurch rebuild to sub-standard landfills? Hon ANNETTE KING to the Minister of Health: Is he satisfied New Zealanders are receiving timely and affordable healthcare? MARK MITCHELL to the Minister of Housing: What reports has he received on positive progress being advanced on the Government's housing agenda? DARIEN FENTON to the Minister of Labour: Does he agree with the Prime Minister's statement on the minimum wage that "I think we've been pretty fair in what we've done in the past and we probably will be in the future"? CLAUDETTE HAUITI to the Minister of Science and Innovation: How are the National Science Challenges bringing together the best scientific talent across New Zealand? HONE HARAWIRA to the Minister for Economic Development: Will he commit to spending the $41m on reducing child poverty, after signalling that he might not now give that money to Team New Zealand to compete in the next America's Cup? Dr RAJEN PRASAD to the Minister of Immigration: When he said in response to an oral question on 29 January 2014 that it was "a pretty simple process…to alert immigration authorities", what was his understanding of the process a complainant would go through? CHRIS AUCHINVOLE to the Associate Minister of Transport: What progress is being made in improving road safety?

Research papers, University of Canterbury Library

A buckling-restrained braced frame (BRBF) is a structural bracing system that provides lateral strength and stiffness to buildings and bridges. They were first developed in Japan in the 1970s (Watanabe et al. 1973, Kimura et al. 1976) and gained rapid acceptance in the United States after the Northridge earthquake in 1994 (Bruneau et al. 2011). However, it was not until the Canterbury earthquakes of 2010/2011, that the New Zealand construction market saw a significant uptake in the use of buckling-restrained braces (BRBs) in commercial buildings (MacRae et al. 2015). In New Zealand there is not yet any documented guidance or specific instructions in regulatory standards for the design of BRBFs. This makes it difficult for engineers to anticipate all the possible stability and strength issues within a BRBF system and actively mitigate them in each design. To help ensure BRBF designs perform as intended, a peer review with physical testing are needed to gain building compliance in New Zealand. Physical testing should check the manufacturing and design of each BRB (prequalification testing), and the global strength and stability of each BRB its frame (subassemblage testing). However, the financial pressures inherent in commercial projects has led to prequalification testing (BRB only testing) being favoured without adequate design specific subassemblage testing. This means peer reviewers have to rely on BRB suppliers for assurances. This low regulation environment allows for a variety of BRBF designs to be constructed without being tested or well understood. The concern is that there may be designs that pose risk and that issues are being overlooked in design and review. To improve the safety and design of BRBFs in New Zealand, this dissertation studies the behaviour of BRBs and how they interact with other frame components. Presented is the experimental test process and results of five commercially available BRB designs (Chapter 2). It discusses the manufacturing process, testing conditions and limitations of observable information. It also emphasises that even though subassemblage testing is impractical, uniaxial testing of the BRB only is not enough, as this does not check global strength or stability. As an alternative to physical testing, this research uses computer simulation to model BRB behaviour. To overcome the traditional challenges of detailed BRB modelling, a strategy to simulate the performance of generic BRB designs was developed (Chapter 3). The development of nonlinear material and contact models are important aspects of this strategy. The Chaboche method is employed using a minimum of six backstress curves to characterize the combined isotropic and kinematic hardening exhibited by the steel core. A simplified approach, adequate for modelling the contact interaction between the restrainer and the core was found. Models also capture important frictional dissipation as well as lateral motion and bending associated with high order constrained buckling of the core. The experimental data from Chapter 2 was used to validate this strategy. As BRBs resist high compressive loading, global stability of the BRB and gusseted connection zone need to be considered. A separate study was conducted that investigated the yielding and buckling strength of gusset plates (Chapter 4). The stress distribution through a gusset plate is complex and difficult to predict because the cross-sectional area of gusset plate is not uniform, and each gusset plate design is unique in shape and size. This has motivated design methods that approximate yielding of gusset plates. Finite element modelling was used to study the development of yielding, buckling and plastic collapse behaviour of a brace end bolted to a series of corner gusset plates. In total 184 variations of gusset plate geometries were modelled in Abaqus®. The FEA modelling applied monotonic uniaxial load with an imperfection. Upon comparing results to current gusset plate design methods, it was found that the Whitmore width method for calculating the yield load of a gusset is generally un-conservative. To improve accuracy and safety in the design of gusset plates, modifications to current design methods for calculating the yield area and compressive strength for gusset plates is proposed. Bolted connections are a popular and common connection type used in BRBF design. Global out-of-plane stability tends to govern the design for this connection type with numerous studies highlighting the risk of instability initiated by inelasticity in the gussets, neck of the BRB end and/or restrainer ends. Subassemblage testing is the traditional method for evaluating global stability. However, physical testing of every BRBF variation is cost prohibitive. As such, Japan has developed an analytical approach to evaluate out-of-plane stability of BRBFs and incorporated this in their design codes. This analytical approach evaluates the different BRB components under possible collapse mechanisms by focusing on moment transfer between the restrainer and end of the BRB. The approach have led to strict criteria for BRBF design in Japan. Structural building design codes in New Zealand, Europe and the United States do not yet provide analytical methods to assess BRB and connection stability, with prototype/subassemblage testing still required as the primary means of accreditation. Therefore it is of interest to investigate the capability of this method to evaluate stability of BRBs designs and gusset plate designs used in New Zealand (including unstiffened gusset connection zones). Chapter 5 demonstrates the capability of FEA to study to the performance of a subassemblage test under cyclic loading – resembling that of a diagonal ground storey BRBF with bolted connections. A series of detailed models were developed using the strategy presented in Chapter 3. The geometric features of BRB 6.5a (Chapter 2) were used as a basis for the BRBs modelled. To capture the different failure mechanisms identified in Takeuchi et al. (2017), models varied the length that the cruciform (non-yielding) section inserts into the restrainer. Results indicate that gusset plates designed according to New Zealand’s Steel Structures Standard (NZS 3404) limit BRBF performance. Increasing the thickness of the gusset plates according to modifications discussed in Chapter 4, improved the overall performance for all variants (except when Lin/ Bcruc = 0.5). The effect of bi-directional loading was not found to notably affect out-of-plane stability. Results were compared against predictions made by the analytical method used in Japan (Takeuchi method). This method was found to be generally conservative is predicting out-of-plane stability of each BRBF model. Recommendations to improve the accuracy of Takeuchi’s method are also provided. The outcomes from this thesis should be helpful for BRB manufacturers, researchers, and in the development of further design guidance of BRBFs.

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.