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Articles, UC QuakeStudies

An edited copy of the pdf transcript of Michelle's second earthquake story, captured by the UC QuakeBox Take 2 project. At the participant's request, parts of this transcript have been redacted. Interviewer: Jennifer Middendorf. Transcriber: Josie Hepburn.

Research papers, University of Canterbury Library

After a high-intensity seismic event, inspections of structural damages need to be carried out as soon as possible in order to optimize the emergency management, as well as improving the recovery time. In the current practice, damage inspections are performed by an experienced engineer, who physically inspect the structures. This way of doing not only requires a significant amount of time and high skilled human resources, but also raises the concern about the inspector’s safety. A promising alternative is represented using new technologies, such as drones and artificial intelligence, which can perform part of the damage classification task. In fact, drones can safely access high hazard components of the structures: for instance, bridge piers or abutments, and perform the reconnaissance by using highresolution cameras. Furthermore, images can be automatically processed by machine learning algorithms, and damages detected. In this paper, the possibility of applying such technologies for inspecting New Zealand bridges is explored. Firstly, a machine-learning model for damage detection by performing image analysis is presented. Specifically, the algorithm was trained to recognize cracks in concrete members. A sensitivity analysis was carried out to evaluate the algorithm accuracy by using database images. Depending on the confidence level desired,i.e. by allowing a manual classification where the alghortim confidence is below a specific tolerance, the accuracy was found reaching up to 84.7%. In the second part, the model is applied to detect the damage observed on the Anzac Bridge (GPS coordinates -43.500865, 172.701138) in Christchurch by performing a drone reconnaissance. Reults show that the accuracy of the damage detection was equal to 88% and 63% for cracking and spalling, respectively.

Articles, UC QuakeStudies

An edited copy of the pdf transcript of Laura's second earthquake story, captured by the UC QuakeBox Take 2 project. At the participant's request, parts of this transcript have been redacted. Interviewer: Jennifer Middendorf. Transcriber: Laura Moir.

Audio, Radio New Zealand

There are hopes an earthquake simulation in Porirua might result in homes being better prepared for a big shake. Houses on Christchurch's Port Hills suffered more damage than houses in other areas during the Canterbury Earthquakes - even though the ground shaking was roughly the same. Now the Earthquake Commission is on a mission to find out why that was - and prevent the same level of damage in a future quake. Checkpoint reporter Logan Church and video journalist Dom Thomas start their report up on a hilly farm above Wellington.

Audio, Radio New Zealand

EQC was ill-prepared to deal with the wide spread damage of the Christchurch Earthquakes and as a consequence its reputation been left in tatters with many seeing the commission as uncaring, miserly and inefficient. That is according to the findings of the inquiry into EQC and its handling of quake claims in Canterbury and Kaikōura. Inquiry Chair Dame Silvia Cartwright lays out a raft of inadequacies including EQC not being equiped to handle a mass scale managed repair programme - leading to multiple mistakes, poor staffing decisions and inadequate quality control. Damage assessments were the root of claimants disputes time and time again. Dame Silvia Cartwright described to Checkpoint the way claimants have been treated by EQC.

Audio, Radio New Zealand

A momentous day in Christchurch as a huge steel frame was installed as part of the stabilisation work for Christ Church Cathedral. Karyn speaks with project director Keith Paterson about the plans to return the famed rose window extensively damage in the 2011 earthquake.

Research papers, University of Canterbury Library

Recent severe earthquakes, such as the 2010-2011 Christchurch earthquake series, have put emphasis on building resilience all over the world. To achieve such resilience, procedures for low damage seismic design have been developed to satisfy both life safety requirements and the need to minimize undesirable economic effects of required building repair or structural member replacement following a major earthquake. Seismic resisting systems following this concept are expected to withstand severe earthquakes without requiring major post-earthquake repairs, using isolating mechanisms or sacrificial systems that either do not need repair or are readily repairable or replaceable. These include the sliding hinge joint with asymmetric friction connections (SHJAFCs) in beam-to-column connections of the moment resisting steel frames (MRSFs) and symmetric friction connections (SFCs) in braces of the braced frames. A 9 m tall, configurable three-storey steel framed composite floor building incorporating frictionbased 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. The structural systems are configurable, allowing different moment and braced frame structural systems tested in two horizontal directions. The structure is designed and detailed to undergo, at worst, minor damage under a planned series of severe earthquakes.

Images, eqnz.chch.2010

This is St Peters Riccarton. It was damaged in one of the two big Earthquakes to hit Christchurch in September 2010 and February 2011. Its taken a LONG time for work to really get going, but now that it is, they are also upgrading and extending the church with a modern annexe.

Research papers, University of Canterbury Library

Field surveys and experimental studies have shown that light steel or timber framed plasterboard partition walls are particularly vulnerable to earthquake damage prompting the overarching objective of this research, which is to further the development of low damage seismic systems for non-structural partition walls in order to facilitate their adoption by industry to assist with reducing the losses associated with the maintenance and repair cost of buildings across their design life. In particular, this study focused on the behaviour of steel-framed partition walls systems with novel detailing that aim to be “low-damage” designed according to common practice for walls used in commercial and institutional buildings in New Zealand. This objective was investigated by (1) investigating the performance of a flexible track system proposed by researchers and industry by experimental testing of full-scale specimens; (2) investigating the performance of the seismic gap partition wall systems proposed in a number of studies, further developed in this study with input from industry, by experimental testing of full-scale specimens; and (3) investigating the potential implications of using these systems compared with traditionally detailed partition wall systems within multi-storey buildings using the Performance Based Earthquake Engineering loss assessment methodology. Three full-scale testing frames were designed in order to replicate, under controlled laboratory conditions, the effects of seismic shaking on partition walls within multi-storey buildings by the application of quasi-static uni-directional cyclic loading imposing an inter-storey drift. The typical configuration for test specimens was selected to be a unique “y-shape”, including one angled return wall, with typical dimensions of approximately 2400 mm along the main wall and 600 mm along (approximately) the returns walls with a height of 2405 mm from floor to ceiling. The specimens were aligned within test frames at an oblique angle to the direction of loading in order to investigate bi- directional effects. Three wall specimens with flexible track detailing, two identical plane specimens and the third including a doorway, were tested. The detailing involved removing top track anchors within the proximity of wall intersections, thus allowing the tracks to ‘bow’ out at these locations. Although the top track anchors were specified to be removed the proximity of wall intersections, a construction error was made whereby a single top track slab to concrete anchor was left in at the three-way wall junction. Despite this error, the experimental testing was deemed worthwhile since such errors will also occur in practice and because the behaviour of the wall can be examined with this fixing in mind. The specimens also included an acoustic/fire sealant at the top lining to floor boundary. In addition to providing drift capacities, the force-displacement behaviour is also reported, the dissipated energy was computed, and the parameters of the Wayne-Stewart hysteretic model were fitted to the results. The specimen with the door opening behaved significantly different to the plane specimens: damage to the doorway specimen began as cracking of the wallboard propagating from the corners of the doorway following which the L- and Y- shaped junctions behaved independently, whereas damage to the plane specimens began as cracking of the wallboard at the top of the L-junction and wall system deformed as a single unit. The results suggest that bi-directional behaviour is important even if its impact cannot be directly quantified by the experiments conducted. Damage to sealant implies that the bond between plasterboard and sealant is important for its seismic performance. Careful quality control is advised as defects in the bond may significantly impact its ability to withstand seismic movement. Two specimens with seismic gap detailing were tested: a steel stud specimen and a timber stud specimen. Observed drift capacities were significantly greater than traditional plasterboard partition systems. Equations were used to predict the drift at which damage state 1 (DS1) and damage state 2 (DS2) would initiate. The equation used to estimate the drift at the onset of DS1 accurately predicted the onset of plaster cracking but overestimated the drift at which the gap filling material was damaged. The equation used to predict the onset of DS2 provided a lower bound for both specimens and also when used to predict results of previous experimental tests on seismic gap systems. The gap-filling material reduced the drift at the onset of DS1, however, it had a beneficial effect on the re-centring behaviour of the linings. Out-of-plane displacements and return wall configuration did not appear to significantly impact the onset of plaster cracking in the specimens. A loss assessment according to the PBEE methodology was conducted on four steel MRF case study buildings: (1) a 4-storey building designed for the Christchurch region, (2) a 4-storey building designed for the Wellington region, (3) a 12-storey building designed for the Christchurch region, and (4) a 12- storey building designed for the Wellington region. The fragility parameters for a traditional partition system, the flexible track partition system, and the seismic gap steel stud and timber stud partition systems were included within the loss assessment. The order (lowest to highest) of each system in terms of the expected annual losses of each building when incorporating the system was, (1) the seismic gap timber stud system, (2) the seismic gap steel stud system, (3) the traditional/baseline system, and (4) the flexible track system. For the seismic gap timber stud system, which incurred the greatest reduction in expected annual losses for each case study building, the reduction in expected annual losses in comparison to the losses found when using the traditional system ranged from a 5% to a 30% reduction. This reinforces the fact that while there is a benefit to the using low damage partition systems in each building the extent of reduction in expected annual losses is significantly dependent on the particular building design and its location. The flexible track specimens had larger repair costs at small hazard levels compared to the traditional system but smaller repair costs at larger hazard levels. However, the resulting expected annual losses for the flexible track system was higher than the traditional system which reinforces findings from past studies which observed that the greatest contribution to expected annual losses arises from low to moderate intensity shaking seismic events (low hazard levels).

Research papers, University of Canterbury Library

The performance of buildings in recent New Zealand earthquakes (Canterbury, Seddon and Kaikōura), delivered stark lessons on seismic resilience. Most of our buildings, with a few notable exceptions, performed as our Codes intended them to, that is, to safeguard people from injury. Many buildings only suffered minor structural damage but were unable to be reused and occupied for significant periods of time due to the damage and failure of non-structural elements. This resulted in substantial economic losses and major disruptions to our businesses and communities. Research has attributed the damage to poor overall design coordination, inadequate or lack of seismic restraints for non structural elements and insufficient clearances between building components to cater for the interaction of non structural elements under seismic actions. Investigations have found a clear connection between the poor performance of non-structural elements and the issues causing pain in the industry (procurement methods, risk aversion, the lack of clear understanding of design and inspection responsibility and the need for better alignment of the design codes to enable a consistent integrated design approach). The challenge to improve the seismic performance of non structural elements in New Zealand is a complex one that cuts across a diverse construction industry. Adopting the key steps as recommended in this paper is expected to have significant co-benefits to the New Zealand construction industry, with improvements in productivity alongside reductions in costs and waste, as the rework which plagues the industry decreases.

Audio, Radio New Zealand

Tomorrow will mark four years since a huge 7.8 magnitude earthquake rocked North Canterbury. As well as severely damaging homes and roads, it left some hill country farms in the area with up to 40 percent of their land unusable. Four years on, sheep and beef farmers are finding new ways to work. Rural reporter, Maja Burry and cameraman Nate McKinnon have the story.

Audio, Radio New Zealand

Moves towards returning the famed rose window to Christ Church Cathedral begin today. An eighteen-tonne steel frame is being installed onto the cathedral's west facade as part of restoration work. It will eventually housing the rose window. The cathedral was critically damaged in the Christchurch earthquake of 2011. Project director Keith Paterson is in Cathedral Square. He speaks to Susie Ferguson.

Audio, Radio New Zealand

The chair of the inquiry in to the Earthquake Commission has grave concerns about the state of the housing stock in Christchurch due to EQC's failure to properly fix quake damage. It's just one of a raft of findings released by Dame Silvia Cartwright today, after a year and a half long inquiry that heard from hundreds of homeowners and key players. Conan Young has the story.

Research papers, University of Canterbury Library

A wide range of reinforced concrete (RC) wall performance was observed following the 2010/2011 Canterbury earthquakes, with most walls performing as expected, but some exhibiting undesirable and unexpected damage and failure characteristics. A comprehensive research programme, funded by the Building Performance Branch of the New Zealand Ministry of Business, Innovation and Employment, and involving both numerical and experimental studies, was developed to investigate the unexpected damage observed in the earthquakes and provide recommendations for the design and assessment procedures for RC walls. In particular, the studies focused on the performance of lightly reinforced walls; precast walls and connections; ductile walls; walls subjected to bi-directional loading; and walls prone to out-of-plane instability. This paper summarises each research programme and provides practical recommendations for the design and assessment of RC walls based on key findings, including recommended changes to NZS 3101 and the NZ Seismic Assessment Guidelines.

Audio, Radio New Zealand

A Christchurch couple locked in an ongoing legal battle with state-owned quake insurer Southern Response says it is sobering for a Court of Appeal decision to go their way, one decade on from the harrowing earthquakes. An earlier High Court decision found Southern Response guilty of misleading and deceptive behaviour when it short-changed Karl and Alison Dodds tens of thousands of dollars after their quake damaged house was written off. The Dodds say they were tricked into accepting a lower offer from Southern Response only to later discover the insurer had kept secret from them a second higher estimate to rebuild their damaged house, a so-called second secret detailed repair and rebuild analysis (DRA). The High Court ordered Southern Response to pay the Dodds almost $180,000 in damages, plus costs. But the government appealed the decision, saying it needed clarity, because of the thousands of similar cases it could be liable for. The Court of Appeal reduced the damages Southern Response has to pay $10,656.44 due to an earlier error in calculations. The Minister responsible Grant Robertson has declined to be interviewed. Southern Response also declined to be interviewed. Neither have ruled out appealing the decision in the Supreme Court.

Audio, Radio New Zealand

On 22 February 2011, Christchurch police sargeant Dave Harvey was outside the earthquake-damaged Hotel Grand Chancellor on Cashel Street, unsure if anyone was trapped inside. In case they were, he grabbed a can of spray paint and painted 'Help is on the way' in one-metre high letters on the road. Harvey's quick thinking really helped the people trapped in the hotel, says Clare Mackey, producer of the new documentary Help is on the Way.

Audio, Radio New Zealand

Some of Christchurch's earthquake damaged red-zone land is another step closer to having some long term decisions made about its future. Today the Minister of Greater Christchurch Regeneration, Megan Woods, formally handed over ownership of 70 hectares of land to the Christchurch City Council. The land gifted to the council is in the coastal suburbs of Southshore, South Brighton and Brooklands, where residents have been waiting almost a decade to find out what the future holds for their area. Rachel Graham reports

Audio, Radio New Zealand

Time is nearly up for owners of on-sold quake damaged properties in Canterbury to apply to claim money for botched repairs. The Government announced last year it would give an ex-gratia payment to home-owners with properties that went over the Earthquake Commission's then cap of $100,000. Today is the last day for applications after the original August deadline was extended due to Covid-19. But there are calls to extend that deadline again, as applications have flooded in over the past month.