Timber-based hybrid structures provide a prospective solution for utilizing environmentally friendly timber material in the construction of mid-rise or high-rise structures. This study mainly focuses on structural damage evaluation for a type of timber-steel hybrid structures, which incorporate prefabricated light wood frame shear walls into steel moment-resisting frames (SMRFs). The structural damage of such a hybrid structure was evaluated through shake table tests on a four-story large-scale timber-steel hybrid structure. Four ground motion records (i.e., Wenchuan earthquake, Canterbury earthquake, El-Centro earthquake, and Kobe earthquake) were chosen for the tests, with the consideration of three different probability levels (i.e., minor, moderate and major earthquakes) for each record. During the shake table tests, the hybrid structure performed quite well with visual damage only to wood shear walls. No visual damage in SMRF and the frame-to-wall connections was observed. The correlation of visual damage to seismic intensity, modal-based damage index and inter-story drift was discussed. The reported work provided a basis of knowledge for performance-based seismic design (PBSD) for such timber-based hybrid structures.
Post-tensioned timber technology was originally developed and researched at the University of Canterbury (UC) in New Zealand in 2005. It can provide a low-damage seismic design solution for multi-storey mass timber buildings. Since mass timber products, such as cross-laminated timber (CLT), have high in-plane stiffness, a post-tensioned timber shear wall will deform mainly in a rocking mechanism. The moment capacity of the wall at the base is commonly determined using the elastic form of the Modified Monolithic Beam Analogy (MMBA). In the calculation of the moment capacity at the wall base, it is critical to accurately predict the location of the neutral axis and the timber compressive stress distribution. Three 2/3 scale 8.6m tall post-tensioned CLT walls were experimentally tested under quasi-static cyclic loading – both uni-directional and bi-directional- in this study. These specimens included a single wall, a coupled wall, and a C-shaped core-wall. The main objective was to develop post-tensioned C-shaped timber core-walls for tall timber buildings with enhanced lateral strength and stiffness. To better understand the timber compressive stress distributions at the wall base, particle tracking technology (PTT) technology was applied for the first time to investigate the behaviour of the compression toe. Previous post-tensioned timber testing primarily used the displacement measurements to determine the timber compressive behavior at the wall base or rocking interfaces. However, by using PTT technology, the timber strain measurements in the compression zone can be much more accurate as PTT is able to track the movement of many particles on the timber surface. This paper presents experimental testing results of post-tensioned CLT walls with a focus on capturing timber compressive behavior using PTT. The PTT measurements were able to better capture small base rotations which occurred at the onset of gap opening and capture unexpected phenomena in core-wall tests. The single wall test result herein presented indicates that while the MMBA could predict the moment rotation behavior with reasonable accuracy, the peak strain response was under predicted in the compression toe. Further detailed study is required to better understand the complex strain fields generated reflective of the inherent cross-thickness inhomogeneity and material variability of CLT.
This study analyses the Earthquake Commission’s (EQC) insurance claims database to investigate the influence of seismic intensity and property damage resulting from the Canterbury Earthquake Sequence (CES) on the repair costs and claim settlement duration for residential buildings. Firstly, the ratio of building repair cost to its replacement cost was expressed as a Building Loss Ratio (BLR), which was further extended to Regional Loss Ratio (RLR) for greater Christchurch by multiplying the average of all building loss ratios with the proportion of building stock that lodged an insurance claim. Secondly, the total time required to settle the claim and the time taken to complete each phase of the claim settlement process were obtained. Based on the database, the regional loss ratio for greater Christchurch for three events producing shakings of intensities 6, 7, and 8 on the modified Mercalli intensity scale were 0.013, 0.066, and 0.171, respectively. Furthermore, small (less than NZD15,000), medium (between NZD15,000 and NZD100,000), and large (more than NZD100,000) claims took 0.35-0.55, 1.95-2.45, and 3.35-3.85 years to settle regardless of the building’s construction period and earthquake intensities. The number of claims was also disaggregated by various building characteristics to evaluate their relative contribution to the damage and repair costs.
Pumice materials, which are problematic from an engineering viewpoint, are widespread in the central part of the North Island. Considering the impacts of the 2010-2011 Christchurch earthquakes, a clear understanding of their properties under earthquake loading is necessary. For example, the 1987 Edgecumbe earthquake showed evidence of localised liquefaction of sands of volcanic origin. To elucidate on this, research was undertaken to investigate whether existing empirical field-based methods to evaluate the liquefaction potential of sands, which were originally developed for hard-grained soils, are applicable to crushable pumice-rich deposits. For this purpose, two sites, one in Whakatane and another in Edgecumbe, were selected where the occurrence of liquefaction was reported following the Edgecumbe earthquake. Manifestations of soil liquefaction, such as sand boils and ejected materials, have been reported at both sites. Field tests, including cone penetration tests (CPT), shear-wave velocity profiling, and screw driving sounding (SDS) tests were performed at the sites. Then, considering estimated peak ground accelerations (PGAs) at the sites based on recorded motions and possible range of ground water table locations, liquefaction analysis was conducted at the sites using available empirical approaches. To clarify the results of the analysis, undisturbed soil samples were obtained at both sites to investigate the laboratory-derived cyclic resistance ratios and to compare with the field-estimated values. Research results clearly showed that these pumice-rich soils do not fit existing liquefaction assessment frameworks and alternate methods are necessary to characterise them.
Low Damage Seismic Design (LDSD) guidance material being developed by Engineering NZ is considering a design drift limit for multi-storey buildings of 0.5% at a new damage control limit state (DCLS). The impact of this new design requirement on the expected annual loss due to repair costs is investigated for a four-storey office building with reinforced concrete walls located in Christchurch. The LDSD guidance material aims to reduce the expected annual loss of complying buildings to below 0.1% of building replacement cost. The research tested this expectation. Losses were estimated in accordance with FEMA P58, using building responses from non-linear time history analyses (performed with OpenSees using lumped plasticity models). The equivalent static method, in line with NZS 1170.5 and NZS 3101, was used to design the building to LDSD specifications, representing a future state-of-practice design. The building designed to low-damage specification returned an expected annual loss of 0.10%, and the building designed conventionally returned an expected annual loss of 0.13%. Limitations with the NZS 3101 method for determining wall stiffness were identified, and a different method acknowledging the relationship between strength and stiffness was used to redesign the building. Along with improving this design assumption, the study finds that LDSD design criteria could be an effective way of limiting damage and losses.
Field surveys and experimental studies have shown that light steel or timber framed plasterboard partition walls are particularly vulnerable to earthquake damage prompting the overarching objective of this research, which is to further the development of low damage seismic systems for non-structural partition walls in order to facilitate their adoption by industry to assist with reducing the losses associated with the maintenance and repair cost of buildings across their design life. In particular, this study focused on the behaviour of steel-framed partition walls systems with novel detailing that aim to be “low-damage” designed according to common practice for walls used in commercial and institutional buildings in New Zealand. This objective was investigated by (1) investigating the performance of a flexible track system proposed by researchers and industry by experimental testing of full-scale specimens; (2) investigating the performance of the seismic gap partition wall systems proposed in a number of studies, further developed in this study with input from industry, by experimental testing of full-scale specimens; and (3) investigating the potential implications of using these systems compared with traditionally detailed partition wall systems within multi-storey buildings using the Performance Based Earthquake Engineering loss assessment methodology. Three full-scale testing frames were designed in order to replicate, under controlled laboratory conditions, the effects of seismic shaking on partition walls within multi-storey buildings by the application of quasi-static uni-directional cyclic loading imposing an inter-storey drift. The typical configuration for test specimens was selected to be a unique “y-shape”, including one angled return wall, with typical dimensions of approximately 2400 mm along the main wall and 600 mm along (approximately) the returns walls with a height of 2405 mm from floor to ceiling. The specimens were aligned within test frames at an oblique angle to the direction of loading in order to investigate bi- directional effects. Three wall specimens with flexible track detailing, two identical plane specimens and the third including a doorway, were tested. The detailing involved removing top track anchors within the proximity of wall intersections, thus allowing the tracks to ‘bow’ out at these locations. Although the top track anchors were specified to be removed the proximity of wall intersections, a construction error was made whereby a single top track slab to concrete anchor was left in at the three-way wall junction. Despite this error, the experimental testing was deemed worthwhile since such errors will also occur in practice and because the behaviour of the wall can be examined with this fixing in mind. The specimens also included an acoustic/fire sealant at the top lining to floor boundary. In addition to providing drift capacities, the force-displacement behaviour is also reported, the dissipated energy was computed, and the parameters of the Wayne-Stewart hysteretic model were fitted to the results. The specimen with the door opening behaved significantly different to the plane specimens: damage to the doorway specimen began as cracking of the wallboard propagating from the corners of the doorway following which the L- and Y- shaped junctions behaved independently, whereas damage to the plane specimens began as cracking of the wallboard at the top of the L-junction and wall system deformed as a single unit. The results suggest that bi-directional behaviour is important even if its impact cannot be directly quantified by the experiments conducted. Damage to sealant implies that the bond between plasterboard and sealant is important for its seismic performance. Careful quality control is advised as defects in the bond may significantly impact its ability to withstand seismic movement. Two specimens with seismic gap detailing were tested: a steel stud specimen and a timber stud specimen. Observed drift capacities were significantly greater than traditional plasterboard partition systems. Equations were used to predict the drift at which damage state 1 (DS1) and damage state 2 (DS2) would initiate. The equation used to estimate the drift at the onset of DS1 accurately predicted the onset of plaster cracking but overestimated the drift at which the gap filling material was damaged. The equation used to predict the onset of DS2 provided a lower bound for both specimens and also when used to predict results of previous experimental tests on seismic gap systems. The gap-filling material reduced the drift at the onset of DS1, however, it had a beneficial effect on the re-centring behaviour of the linings. Out-of-plane displacements and return wall configuration did not appear to significantly impact the onset of plaster cracking in the specimens. A loss assessment according to the PBEE methodology was conducted on four steel MRF case study buildings: (1) a 4-storey building designed for the Christchurch region, (2) a 4-storey building designed for the Wellington region, (3) a 12-storey building designed for the Christchurch region, and (4) a 12- storey building designed for the Wellington region. The fragility parameters for a traditional partition system, the flexible track partition system, and the seismic gap steel stud and timber stud partition systems were included within the loss assessment. The order (lowest to highest) of each system in terms of the expected annual losses of each building when incorporating the system was, (1) the seismic gap timber stud system, (2) the seismic gap steel stud system, (3) the traditional/baseline system, and (4) the flexible track system. For the seismic gap timber stud system, which incurred the greatest reduction in expected annual losses for each case study building, the reduction in expected annual losses in comparison to the losses found when using the traditional system ranged from a 5% to a 30% reduction. This reinforces the fact that while there is a benefit to the using low damage partition systems in each building the extent of reduction in expected annual losses is significantly dependent on the particular building design and its location. The flexible track specimens had larger repair costs at small hazard levels compared to the traditional system but smaller repair costs at larger hazard levels. However, the resulting expected annual losses for the flexible track system was higher than the traditional system which reinforces findings from past studies which observed that the greatest contribution to expected annual losses arises from low to moderate intensity shaking seismic events (low hazard levels).
This chapter will draw on recent literature and practice experience to discuss the nature of field education in Aotearoa New Zealand. Social work education in this country is provided by academic institutions that are approved by the Social Workers Registration Board. The field education curriculum is therefore shaped by both the regulatory body and the tertiary institutions. Significant numbers of students undertake field education annually which places pressure on industry and raises concerns as to the quality of student experience. Although the importance of field education is undisputed it remains poised in a liminal space between the tertiary education and social service sectors where it is not sufficiently resourced by either. This affects the provision of practice placements as well as the establishment of long-term cross-sector partnerships. Significant events such as the 2010 and 2011 Christchurch earthquakes and recent terrorist attacks have exposed students to different field education experiences signalling the need for programmes to be responsive. Examples of creative learning opportunities in diverse environments, including in indigenous contexts, will be described. Drawing upon recent research, we comment on student and field educator experiences of supervision in the field. Recommendations to further develop social work field education in Aotearoa New Zealand relate to resourcing, infrastructure and quality, support for field educators, and assessment.
To reduce seismic vulnerability and the economic impact of seismic structural damage, it is important to protect structures using supplemental energy dissipation devices. Several types of supplemental damping systems can limit loads transferred to structures and absorb significant response energy without sacrificial structural damage. Lead extrusion dampers are one type of supplemental energy dissipation devices. A smaller volumetric size with high force capacities, called high force to volume (HF2V) devices, have been employed in a large series of scaled and full-scaled experiments, as well as in three new structures in Christchurch and San Francisco. HF2V devices have previously been designed using very simple models with limited precision. They are then manufactured, and tested to ensure force capacities match design goals, potentially necessitating reassembly or redesign if there is large error. In particular, devices with a force capacity well above or below a design range can require more testing and redesign, leading to increased economic and time cost. Thus, there is a major need for a modelling methodology to accurately estimate the range of possible device force capacity values in the design phase – upper and lower bounds. Upper and lower bound force capacity estimates are developed from equations in the metal extrusion literature. These equations consider both friction and extrusion forces between the lead and the bulged shaft in HF2V devices. The equations for the lower and upper bounds are strictly functions of device design parameters ensuring easy use in the design phase. Two different sets of estimates are created, leading to estimates for the lower and upper bounds denoted FLB,1, FUB,1, FUB,2, respectively. The models are validated by comparing the bounds with experimental force capacity data from 15 experimental HF2V device tests. All lower bound estimates are below or almost equal to the experimental device forces, and all upper bound estimates are above. Per the derivation, the (FLB,1, FUB,1) pair provide narrower bounds. The (FLB,1, FUB,1) pair also had a mean lower bound gap of -34%, meaning the lower bound was 74% of device force on average, while the mean upper bound gap for FUB,1 was +23%. These are relatively tight bounds, within ~±2 SE of device manufacture, and can be used as a guide to ensure device forces are in range for the actual design use when manufactured. Therefore, they provide a useful design tool.
Nel presente articolo si illustra una procedura per il processamento automatizzato di prove CPT, il calcolo di vari indici di liquefazione e la rappresentazione dei dati su mappa. La procedura è applicata al caso studio del terremoto di Christchurch, Nuova Zelanda, del 22 febbraio 2011 (magnitudo momento, Mw = 6.2). Dall’analisi spaziale dei risultati emerge una buona correlazione tra le mappe ottenute per l’indicatore degli effetti al suolo e i danni osservati (su terreni e strutture). Tuttavia, per confermare la validità di tale procedura, sarà necessario esaminare ulteriori casi studio nel mondo.
Climate change and population growth will increase vulnerability to natural and human-made disasters or pandemics. Longitudinal research studies may be adversely impacted by a lack of access to study resources, inability to travel around the urban environment, reluctance of sample members to attend appointments, sample members moving residence and potentially also the destruction of research facilities. One of the key advantages of longitudinal research is the ability to assess associations between exposures and outcomes by limiting the influence of sample selection bias. However, ensuring the validity and reliability of findings in longitudinal research requires the recruitment and retention of respondents who are willing and able to be repeatedly assessed over an extended period of time. This study examined recruitment and retention strategies of 11 longitudinal cohort studies operating during the Christchurch, New Zealand earthquake sequence which began in September 2010, including staff perceptions of the major impediments to study operations during/after the earthquakes and respondents’ barriers to participation. Successful strategies to assist recruitment and retention after a natural disaster are discussed. With the current COVID-19 pandemic, longitudinal studies are potentially encountering some of the issues highlighted in this paper including: closure of facilities, restricted movement of research staff and sample members, and reluctance of sample members to attend appointments. It is possible that suggestions in this paper may be implemented so that longitudinal studies can protect the operation of their research programmes.<br /><br />Key messages<br /><ul><li>Recruitment and retention of longitudinal study participants is challenging following a natural disaster.</li><br /><li>The long-lasting, global effects of the Covid 19 pandemic will increase this problem.</li><br /><li>Longitudinal study researchers should develop protocols to support retention before a disaster occurs.</li><br /><li>Researchers need to be pragmatic and flexible in the design and implementation of their studies.</li></ul>
Supplemental energy dissipation devices are increasingly used to protect structures, limit loads transferred to structural elements and absorbing significant response energy without sacrificial structural damage. Lead extrusion dampers are supplemental energy dissipation devices, where recent development of smaller volumetric size with high force capacities, called high force to volume (HF2V) devices, has seen deployment in a large series of scaled and full-scaled experiments, as well as in three new structures in Christchurch, NZ and San Francisco, USA. HF2V devices have previously been designed using limited precision models, so there is variation in force prediction capability. Further, while the overall resistive force is predicted, the knowledge of the relative contributions of the different internal reaction mechanisms to these overall resistive forces is lacking, limiting insight and predictive accuracy in device design. There is thus a major need for detailed design models to better understand force generation, and to aid precision device design. These outcomes would speed the overall design and implementation process for uptake and use, reducing the need for iterative experimental testing. Design parameters from 17 experimental HF2V device tests are used to create finite element models using ABAQUS. The analysis is run using ABAQUS Explicit, in multiple step times of 1 second with automatic increments, to balance higher accuracy and computational time. The output is obtained from the time- history output of the contact pressure forces including the normal and friction forces on the lead along the shaft. These values are used to calculate the resistive force on the shaft as it moves through the lead, and thus the device force. Results of these highly nonlinear, high strain analyses are compared to experimental device force results. Model errors compared to experimental results for all 17 devices ranged from 0% to 20% with a mean absolute error of 6.4%, indicating most errors were small. In particular, the standard error in manufacturing is SE = ±14%. In this case, 15 of 17 devices (88%) are within ±1SE (±14%) and 2 of 17 devices (12%) are within ±2SE (±28). These results show low errors and a distribution of errors compared to experimental results that are within experimental device construction variability. The overall modelling methodology is objective and repeatable, and thus generalizable. The exact same modelling approach is applied to all devices with only the device geometry changing. The results validate the overall approach with relatively low error, providing a general modelling methodology for accurate design of HF2V devices.
Media law developments have continued across many areas in the period to mid-2013. In defamation, the New Zealand courts have begun to consider the issue of third party liability for publication on the internet, with cases involving Google searches and comments on a Facebook page. A parliamentary inquiry into a case that restricted parliamentary privilege has recommended a Parliamentary Privilege Act containing a definition of ‘proceedings in Parliament’. A satirical website increased its popularity when it fought off threatened defamation proceedings. In breach of confidence, a government body, the Earthquake Commission, obtained an interim injunction prohibiting publication of information accidentally released that dealt with the repair of earthquake-damaged properties in Christchurch, and a blogger made the information available online in breach of the order.
Reconnaissance reports have highlighted the poor performance of non-ductile reinforced concrete buildings during the 2010-11 Canterbury earthquakes. These buildings are widely expected to result in significant losses under future earthquakes due to their seismic vulnerability and prevalence in densely populated urban areas. Wellington, for example, contains more than 70 pre-1970s multi-storey reinforced concrete buildings, ranging in height from 5 to 18 storeys. This study seeks to characterise the seismic performance and evaluate the likely failure modes of a typical pre-1970s reinforced concrete building in Wellington, by conducting advanced numerical simulations to evaluate its 3D nonlinear dynamic response. A representative 9-storey office building constructed in 1951 is chosen for this study and modelled in the finite element analysis programme DIANA, using a previously developed and validated approach to predict the failure modes of doubly reinforced walls with confined boundary regions. The structure consists of long walls and robust framing elements resulting in a stiff lateral load resisting system. Barbell-shaped walls are flanked by stiff columns with sufficient transverse reinforcement to serve as boundary regions. Curved shell elements are used to model the walls and their boundary columns, for which the steel reinforcement is explicitly modelled. Line elements are used to model the frame elements. The steel reinforcement in each member is explicitly modelled. The floor slabs are modelled using elastic shell elements. The model is analysed under short and long duration ground motions selected to match site specific targets in Wellington at the DBE and MCE intensity levels. The observed response of the building including drift profiles at each intesity level, strain localization effects around wall openings, and the influence of bidirectional loading are discussed.
This study explores the nature of smaller businesses’ resilience following two major earthquakes that severely disrupted their place of doing business. Data from the owners of ten smaller businesses are qualitative and longitudinal, spanning the period 2011 through 2018, providing first-hand narrative accounts of their responses in the earthquakes’ aftermath. All ten owners showed some individual resilience; six businesses survived through to 2018, of which three have recovered strongly. All three owned their premises; operated business-tobusiness models; and were able to adapt and continue to follow path-extension strategies. All the other businesses had direct business-to-customer models operating from leased premises, typically in major retail malls. Four eventually recognised path-exhaustion at different times and so did not survive through to 2018. We conclude however that post-disaster recovery is best explained in terms of business model resilience. Even the most resilient of individual owners will struggle to survive if their business model is either not resilient or cannot be made so. Individual resilience is necessary but not sufficient.
This article explores the scope of small-scale radio to create an auditory geography of place. It focuses on the short-term art radio project The Stadium Broadcast, which was staged in November 2014 in an earthquake-damaged sports stadium in Christchurch, New Zealand. Thousands of buildings and homes in Christchurch have been demolished since the February 22, 2011, earthquake, and by the time of the broadcast the stadium at Lancaster Park had been unused for three years and nine months, and its future was uncertain. The Stadium Broadcast constructed a radio memorial to the Park’s 130-year history through archival recordings, the memories of local people, observation of its current state, and a performed site-specificity. The Stadium Broadcast reflected on the spatiality of radio sounds and transmissions, memory, postdisaster transitionality, and the impermanence of place.
Recent tsunami events have highlighted the importance of effective tsunami risk management strategies (including land-use planning, structural and natural mitigation, warning systems, education and evacuation planning). However, the rarity of tsunami means that empirical data concerning reactions to tsunami warnings and evacuation behaviour is rare when compared to findings for evacuations from other hazards. More knowledge is required to document the full evacuation process, including responses to warnings, pre-evacuation actions, evacuation dynamics, and the return home. Tsunami evacuation modelling has the potential to inform evidence-based tsunami risk planning and response. However, to date, tsunami evacuation models have largely focused on the timings of evacuations, rather than behaviours of those evacuating. In this research, survey data was gathered from coastal communities in Banks Peninsula and Christchurch, New Zealand, relating to behaviours and actions during the November 14th 2016 Kaikōura earthquake tsunami. Survey questions asked about immediate actions following the earthquake shaking, reactions to tsunami warnings, pre-evacuation actions, evacuation dynamics and details on congestion. This data was analysed to characterise trends and identify factors that influenced evacuation actions and behaviour, and was further used to develop a realistic evacuation model prototype to evaluate the capacity of the roading network in Banks Peninsula during a tsunami evacuation. The evacuation model incorporated tsunami risk management strategies that have been implemented by local authorities, and exposure and vulnerability data, alongside the empirical data collected from the survey. This research enhances knowledge of tsunami evacuation behaviour and reactions to tsunami warnings, and can be used to refine evacuation planning to ensure that people can evacuate efficiently, thereby reducing their tsunami exposure and personal risk.
Designing a structure for higher- than-code seismic performance can result in significant economic and environmental benefits. This higher performance can be achieved using the principles of Performance-Based Design, in which engineers design structures to minimize the probabilistic lifecycle seismic impacts on a building. Although the concept of Performance-Based Design is not particularly new, the initial capital costs associated with designing structures for higher performance have historically hindered the widespread adoption of performance-based design practices. To overcome this roadblock, this research is focused on providing policy makers and stakeholders with evidence-based environmental incentives for designing structures in New Zealand for higher seismic performance. In the first phase of the research, the environmental impacts of demolitions in Christchurch following the Canterbury Earthquakes were quantified to demonstrate the environmental consequences of demolitions following seismic events. That is the focus here. A building data set consisting of 142 concrete buildings that were demolished following the earthquake was used to quantify the environmental impacts of the demolitions in terms of the embodied carbon and energy in the building materials. A reduced set of buildings was used to develop a material takeoff model to estimate material quantities in the entire building set, and a lifecycle assessment tool was used to calculate the embodied carbon and energy in the materials. The results revealed staggering impacts in terms of the embodied carbon and energy in the materials in the demolished buildings. Ongoing work is focused developing an environmental impact framework that incorporates all the complex factors (e.g. construction methodologies, repair methodologies (if applicable), demolition methodologies (if applicable), and waste management) that contribute to the environmental impacts of building repair and demolition following earthquakes.
Shaking table testing of a full-scale three storey resilient and reparable complete composite steel framed building system is being conducted. The building incorporates a number of interchangeable seismic resisting systems of New Zealand and Chinese origin. The building has a steel frame and cold formed steel-concrete composite deck. Energy is dissipated by means of friction connections. These connections are arranged in a number of structural configurations. Typical building nonskeletal elements (NSEs) are also included. Testing is performed on the Jiading Campus shaking table at Tongji University, Shanghai, China. 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 BRANZ, Comflor, Earthquake Commission, HERA, QuakeCoRE, QuakeCentre, University of Auckland, and the University of Canterbury. This paper provides a general overview of the project describing a number of issues encountered in the planning of this programme including issues related to international collaboration, the test plan, and technical issues.
Disaster recovery involves the restoration, repair and rejuvenation of both hard and soft infrastructure. In this report we present observationsfrom seven case studies of collaborative planning from post-earthquake Canterbury, each of which was selected as a means of better understanding ‘soft infrastructure for hard times’. Though our investigation is located within a disaster recovery context, we argue that the lessons learned are widely applicable. Our seven case studies highlighted that the nature of the planning process or journey is as important as the planning objective or destination. A focus on the journey can promote positive outcomes in and of itself through building enduring relationships, fostering diverse leaders, developing new skills and capabilities, and supporting translation and navigation. Collaborative planning depends as much upon emotional intelligence as it does technical competence, and we argue that having a collaborative attitude is more important than following prescriptive collaborative planning formulae. Being present and allowing plenty of time are also key. Although deliberation is often seen as an improvement on technocratic and expertdominated decision-making models, we suggest that the focus in the academic literature on communicative rationality and discursive democracy has led us to overlook other more active forms of planning that occur in various sites and settings. Instead, we offer an expanded understanding of what planning is, where it happens and who is involved. We also suggest more attention be given to values, particularly in terms of their role as a compass for navigating the terrain of decision-making in the collaborative planning process. We conclude with a revised model of a (collaborative) decision-making cycle that we suggest may be more appropriate when (re)building better homes, towns and cities.
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This study provides an initial examination of source parameter uncertainty in a New Zealand ground motion simulation model, by simulating multiple event realisations with perturbed source parameters. Small magnitude events in Canterbury have been selected for this study due to the small number of source input parameters, the wealth of recorded data, and the lack of appreciable off-fault non-linear effects. Which provides greater opportunity to identify systematic source, path and site effects, required to robustly investigate the causes of uncertainty.
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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
Recycling is often employed as part of a disaster waste management system. However, the feasibility, method and effectiveness of recycling varies between disaster events. This qualitative study is based on literature reviews, expert interviews and active participatory research of five international disaster events in developed countries (2009 Victorian Bushfires, Australia; 2009 L’Aquila earthquake, Italy; 2005 Hurricane Katrina, United States; 2010 and 2011 Canterbury earthquakes, New Zealand; 2011 Great East Japan earthquake) to answer three questions: What are the main factors that affect the feasibility of recycling post-disaster? When is on-site or off-site separation more effective? What management approaches improve recycling effectiveness? Seven disaster-specific factors need to be assessed to determine the feasibility of disaster waste recycling programmes: volume of waste; degree of mixing of waste; human and environmental health hazards; areal extent of the waste; community priorities; funding mechanisms; and existing and disaster-specific regulations. The appropriateness of on or off-site waste separation depends on four factors: time constraints; resource availability; degree of mixing of waste and human and public health hazards. Successful recycling programmes require good management including clear and well enforced policies (through good contracts or regulations) and pre-event planning. Further research into post-disaster recycling markets, funding mechanisms and recycling in developing countries is recommended.
Lake Taupō in New Zealand is associated with frequent unrest and small to moderate eruptions. It presents a high consequence risk scenario with immense potential for destruction to the community and the surrounding environment. Unrest associated with eruptions may also trigger earthquakes. While it is challenging to educate people about the hazards and risks associated with multiple eruptive scenarios, effective education of students can lead to better mitigation strategies and risk reduction. Digital resources with user-directed outcomes have been successfully used to teach action oriented skills relevant for communication during volcanic crisis [4]. However, the use of choose your own adventure strategies to enhance low probability risk literacy for Secondary school outreach has not been fully explored. To investigate how digital narrative storytelling can mediate caldera risk literacy, a module “The Kid who cried Supervolcano” will be introduced in two secondary school classrooms in Christchurch and Rotorua. The module highlights four learning objectives: (a) Super-volcanoes are beautiful but can be dangerous (b) earthquake (unrest) activity is normal for super-volcanoes (c) Small eruptions are possible from super-volcanoes and can be dangerous in our lifetimes (d) Super-eruptions are unlikely in our lifetimes. Students will create their digital narrative using the platform Elementari (www.elementari.io). The findings from this study will provide clear understanding of students’ understanding of risk perceptions of volcanic eruption scenarios and associated hazards and inform the design of educational resources geared towards caldera risk literacy.
Following the 2010/2011 Canterbury earthquakes, approximately 60% of multi-story buildings with reinforced concrete walls required demolition. Both practitioners and researchers have increasingly realized that low-damage structural systems could be an alternative to improve the seismic behaviour of concrete buildings and to reduce the economic and social impact of structural damage in future earthquakes. To verify the seismic response of a low-damage concrete wall building representing state-of-art design practice, a shake table test on a two-story concrete building was recently conducted as part of an ILEE-QuakeCoRE collaborative research program. The building utilized flexible wall-to-floor connections in the long span direction and isolating wall-to-floor devices in the short span direction to provide a comparison of their respective behaviour. Additionally, the wall-to-floor interaction such as effects of wall uplift on the link slab, and force transfer mechanism from floor to the wall will be discussed in this paper.
Unreinforced masonry (URM) structures comprise a majority of the global built heritage. The masonry heritage of New Zealand is comparatively younger to its European counterparts. In a country facing frequent earthquakes, the URM buildings are prone to extensive damage and collapse. The Canterbury earthquake sequence proved the same, causing damage to over _% buildings. The ability to assess the severity of building damage is essential for emergency response and recovery. Following the Canterbury earthquakes, the damaged buildings were categorized into various damage states using the EMS-98 scale. This article investigates machine learning techniques such as k-nearest neighbors, decision trees, and random forests, to rapidly assess earthquake-induced building damage. The damage data from the Canterbury earthquake sequence is used to obtain the forecast model, and the performance of each machine learning technique is evaluated using the remaining (test) data. On getting a high accuracy the model is then run for building database collected for Dunedin to predict expected damage during the rupture of the Akatore fault.
Light timber framed (LTF) structures provide a cost-effective and structurally efficient solution for low-rise residential buildings. This paper studies seismic performance of single-storey LTF buildings sheathed by gypsum-plasterboards (GPBs) that are a typical lining product in New Zealand houses. Compared with wood-based structural panels, GPBs tend to be more susceptible to damage when they are used in bracing walls to resist earthquake loads. This study aims to provide insights on how the bracing wall irregularity allowed by the current New Zealand standard NZS 3604 and the in-plane rigidity of ceiling diaphragms affect the overall seismic performance of these GPB-braced LTF buildings. Nonlinear time-history analyses were conducted on a series of single-storey baseline buildings with different levels of bracing wall irregularities and ceiling diaphragm rigidity. The results showed significant torsional effect caused by the eccentric bracing wall layout with semi-rigid/rigid ceiling diaphragms. On average, bracing wall drift demand caused by the extreme bracing wall irregularities was three times of that in the regular bracing wall layout under the rigid diaphragm assumption. This finding agreed well with the house survey after the 2011 Canterbury Earthquake in which significantly more damage was observed in the houses with irregular bracing wall layouts and relatively rigid diaphragms. Therefore, it is recommended to limit the level of bracing wall eccentricity and ensure the sufficiently rigid diaphragms to avoid excessive damage in these LTF buildings in future events.
There is an increasing recognition that the seismic performance of buildings will be affected by the behaviour of both structural and non-structural elements. In light of this, work has been progressing at the University of Canterbury to develop guidelines for the seismic assessment of commercial glazing systems. This paper reviews the seismic assessment guidelines prescribed in Section C10 of the MBIE building assessment guidelines. Subsequently, the C10 approach is used to assess the drift capacity of a number of glazing units recently tested at the University of Canterbury. Comparing the predicted and observed drift capacities, it would appear that the C10 guidelines may lead to nonconservative estimates of drift capacity. Furthermore, the experimental results indicate that watertightness may be lost at very low drift demands, suggesting that guidance for the assessment of serviceability performance would also be beneficial. As such, it is proposed that improved guidance be provided to assist engineers in considering the possible impact that glazing could have on the structural response of a building in a large earthquake.
Glazing systems are non-structural elements in a building that, more often than not, appear to be given little consideration in seismic design. Recent experimental work into glazing systems at the University of Canterbury, however, has shown that glazing systems can be very susceptible to serviceability damage, defined as loss of water-tightness. The focus of this paper is to highlight the difference in vulnerability of standard and seismic glazing systems and consider the implications of this for future repair costs and losses. The paper first describes the damage states chosen for glazing units according to the repair strategies required and expected repair costs. This includes three damage states: DS1: Water Leakage, DS2: Gasket Failure and DS3: Frame/Glass Failure. Implementing modern performance-based earthquake engineering, the paper proceeds to highlight a case study comparing costs and expected losses of a standard glazing unit and a seismic glazing unit installed on a case study building. It is shown that the use of seismic glazing units is generally beneficial over time, due to the early onset of serviceability damage in standard glazing units. Finally, the paper provides suggestions for designers aimed at reducing costs related to earthquake induced repairs of glazing.
