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Research papers, The University of Auckland Library

The connections between walls of unreinforced masonry (URM) buildings and flexible timber diaphragms are critical building components that must perform adequately before desirable earthquake response of URM buildings may be achieved. Field observations made during the initial reconnaissance and the subsequent damage surveys of clay brick URM buildings following the 2010/2011 Canterbury, New Zealand earthquakes revealed numerous cases where anchor connections joining masonry walls or parapets with roof or floor diaphragms appeared to have failed prematurely. These observations were more frequent for adhesive anchor connections than for through-bolt connections (i.e. anchorages having plates on the exterior façade of the masonry walls). Subsequently, an in-field test program was undertaken in an attempt to evaluate the performance of adhesive anchor connections between unreinforced clay brick URM walls and roof or floor diaphragms. The study consisted of a total of almost 400 anchor tests conducted in eleven existing URM buildings located in Christchurch, Whanganui and Auckland. Specific objectives of the study included the identification of failure modes of adhesive anchors in existing URM walls and the influence of the following variables on anchor load-displacement response: adhesive type, strength of the masonry materials (brick and mortar), anchor embedment depth, anchor rod diameter, overburden level, anchor rod type, quality of installation and the use of metal mesh sleeve. In addition, the comparative performance of bent anchors (installed at an angle of minimum 22.5o to the perpendicular projection from the wall surface) and anchors positioned horizontally was investigated. Observations on the performance of wall-to-diaphragm connections in the 2010/2011 Canterbury earthquakes, a snapshot of the performed experimental program and the test results and a preliminary proposed pull-out capacity of adhesive anchors are presented herein.

Research papers, University of Canterbury Library

To this extent, modern buildings generally demonstrated good resistance to collapse during the recent earthquakes in New Zealand. However, damage to non-structural elements (NSE) has been persistent during these events. NSEs include secondary systems or components attached to the floors, roofs, and walls of a building or industrial facility that are not explicitly designed to participate in the main vertical or lateral load-bearing mechanism of the structure. They play a major role in the operational and functional aspects of buildings and contribute a major portion of the building’s overall cost. Therefore, they are expected to accommodate the effects of seismic actions such as drifts and accelerations. Typical examples of NSEs include internal non-loadbearing partitions, suspended ceilings, sprinkler piping systems, architectural claddings, building contents, mechanical/electrical equipment, and furnishings. The main focus of this thesis is the drift sensitive NSEs: precast concrete cladding panels and internal partition walls. Even though most precast concrete cladding panels performed well from a life-safety point of view during recent earthquakes in NZ, some collapsed panels posed a significant threat to life safety. It is, therefore, important that the design and detailing of the panel-to-structure connections ensure that their strength and displacement capacity are adequate to meet the corresponding seismic demands, at least during design level earthquakes. In contrast, the partition wall is likely to get damaged and lose serviceability at a low inter-story drift unless designed to accommodate the relative deformations between them and the structure. Partition walls suffered wide-ranging damage such as screw failures, diagonal cracking, detachments to the gypsum linings, and anchorage failures during the 2011 Canterbury Earthquake Sequence in NZ. Therefore, the thesis is divided into two parts. Part I of the thesis focuses on developing novel low-damage precast concrete cladding panel connections, i.e. “rocking” connection details comprising vertically slotted steel embeds and weld plates. The low-damage seismic performance of novel “rocking” connection details is verified through experimental tests comprising uni-directional, bi-directional, and multi-storey scaled quasi-static cyclic tests. Comparison with the seismic performance of traditional panel connections reported in the literature demonstrated the system’s significantly improved seismic resilience. Furthermore, the finite element models of panel connections and sealants are developed in ABAQUS. The force-drift responses of the “rocking” panel system modelled in SAP2000 is compared with the experimental results to evaluate their accuracy and validity. Part II of the thesis focuses on a) understanding the seismic performance of traditional rigid timber-framed partition wall, b) development and verification of low-damage connections (i.e. “rocking” connection details comprising of dual-slot tracks), and c) seismic evaluation of partition walls with a novel “bracketed and slotted” connections (comprising of innovative fastener and plastic bracket named Flexibracket) under uni-directional and bidirectional quasi-static cyclic loadings. Moreover, parametric investigation of the partition walls was conducted through several experimental tests to understand better the pros and cons of the rocking connection details. The experimental results have confirmed that the implementation of the proposed low damage solutions of precast cladding panels and internal partition walls can significantly reduce their damage in a building.

Audio, Radio New Zealand

Despite a hasty retreat from its iconic building in Christchurch's Square following the February earthquake, 'The Press', is in celebration mode. It's 150 years since the paper began with a six page edition that sold for six pence. It's first pages warned of the crippling cost of a new tunnel and rail line connecting Lyttelton to Christchurch, and on the back, a for sale ad for 100,000 gorse plants! Deb Nation finds the paper celebrated their centenary 50 years earlier, with memories of pigeon post and paper boys.

Audio, Radio New Zealand

In the hours after the February 2011 Canterbury earthquake, Chessie Henry's father Chris Henry, a Kaikoura-based doctor, crawled into makeshift tunnels in the collapsed CTV building to rescue the living and look for the dead. Six years later, Chessie interviewed Chris in an attempt to understand the trauma that lead her father to burnout. In her book just published, We Can Make A Life: A memoir of family, earthquakes and courage, Chessie Henry considers the psychological cost of heroism and unravels stories and memories from her family history.

Audio, Radio New Zealand

Its budget may have blown out by almost a third more than the original figure, but this weekend the doors to the Christchurch Town Hall will re-open for the first time since the 2011 earthquakes. It was touch and go whether the 47 year-old building would even be repaired after the 6.2 quake eight years ago today. 167-million-dollars later and the city is finally getting its town hall back. Conan Young was allowed inside for a sneak peak ahead of Saturday's official opening.

Audio, Radio New Zealand

The company running the restoration of Christchurch's Anglican Cathedral is confident it will be able to raise the extra $51 million still needed to finish the job, and says potential large donors are already being approached here and overseas. The building has sat derelict since the 2011 earthquake and now the cost to fix it has soared from an original estimate of $104 million to $154 million. Some Cantabrians are finding the price hard to justify. The director of the restoration project Keith Paterson speaks to Corin Dann.

Audio, Radio New Zealand

The public policy think tank, the New Zealand Initiative, says this country is still under-prepared for the next big earthquake. The group of economists has reviewed the policy response to the Canterbury earthquakes and has just released its report: Recipe for disaster: Building policy on shaky ground. It says recovery from the quakes was hindered by avoidable policy mistakes that still haven't been addressed. One of the report's co authors Dr Eric Crampton joins Susie Ferguson to discuss the issues.

Audio, Radio New Zealand

The much loved 'Dux de Lux' pub in Christchurch could be set to open its doors again in the next few years if enough money can be raised to restore it. The building was badly damaged by the earthquake in 2011 and a group looking to rebuild the pub say it could take around 12 million dollars to see it welcoming Cantabrians back. James Stewart of Gemelli Consulting had a yarn with Nathan Rarere about a couple of schemes to raise the money.

Audio, Radio New Zealand

A Christchurch man with terminal cancer is using his final days to battle his insurance company, a decade on from the deadly earthquakes. Brian Shaw owns an apartment that's in a block of 11. They were all damaged in 2011. Shaw is a building consent officer. He says getting technical reports and chasing a settlement with insurer Vero has already cost the unit owners about $400,000, and they still have not even made it to court. On Friday morning he will be protesting outside Vero's Christchurch office, along with other unhappy customers.

Audio, Radio New Zealand

It was so nearly lost. As the Christ Church Anglican Cathedral is being rebuilt, historian Edmund Bohan is releasing a history of the distinctive Gothic building. It shows it was controversial even before work started on designing it, let alone building in. From the laying of the foundations to the official opening, it took 40 years, after squabbles over pretty much every aspect of its construction - not to mention the huge problems raising the money to build it in the City Centre. In Heart of the City: The Story of Christchurch's Controversial Cathedral, Edmund is critical of the former Anglican Bishop Victoria Matthews' determination to demolish the badly-damaged cathedral after the Canterbury earthquakes, to replace it with a modern church. And he tells Lynn Freeman he's very much looking forward to seeing the Cathedral restored to its former glory after a lengthy and pricey rebuild. But first he sets the scene. Back in the 1860s, there was controversy over where the cathedral should go, its design, whether it should be in stone or timber - even if there should be a cathedral built at all! Heart of the City: The Story of Christchurch's Controversial Cathedral, by Edmund Bohan is published by Quentin Wilson Publishing.

Research papers, University of Canterbury Library

Seismically vulnerable buildings constitute a major problem for the safety of human beings. In many parts of the world, reinforced concrete (RC) frame buildings designed and constructed with substandard detailing, no consideration of capacity design principles, and improper or no inclusion of the seismic actions, have been identified. Amongst those vulnerable building, one particular typology representative of the construction practice of the years previous to the 1970’s, that most likely represents the worst case scenario, has been widely investigated in the past. The deficiencies of that building typology are related to non-ductile detailing in beam column joints such as the use of plain round bars, the lack of stirrups inside the joint around the longitudinal reinforcement of the column, the use of 180° end hooks in the beams, the use of lap splices in potential ‘plastic hinge’ regions, and substandard quality of the materials. That type of detailing and the lack of a capacity design philosophy create a very fragile fuse in the structure where brittle inelastic behaviour is expected to occur, which is the panel zone region of exterior beam column joints. The non-ductile typology described above was extensively investigated at the University of Canterbury in the context of the project ‘Retrofit Solutions for New Zealand Multi-Storey Buildings’ (2004-2011), founded by the ‘Foundation for Research, Science and Technology’ Tūāpapa Rangahau Pūtaiao. The experimental campaign prior to the research carried out by the author consisted of quasi-static tests of beam column joint subassemblies subjected to lateral loading regime, with constant and varying axial load in the column. Most of those specimens were representative of a plane 2D frame (knee joint), while others represented a portion of a space 3D frame (corner joints), and only few of them had a floor slab, transverse beams, and lap splices. Using those experiments, several feasible, cost-effective, and non-invasive retrofit techniques were developed, improved, and refined. Nevertheless, the slow motion nature of those experiments did not take into account the dynamical component inherent to earthquake related problems. Amongst the set of techniques investigated, the use of FRP layers for strengthening beam column joints is of particular interest due to its versatility and the momentum that its use has gained in the current state of the practice. That particular retrofit technique was previously used to develop a strengthening scheme suitable for plane 2D and space 3D corner beam column joints, but lacking of floor slabs. In addition, a similar scheme was not developed for exterior joints of internal frames, referred here as ‘cruciform’. In this research a 2/5 scale RC frame model building comprising of two frames in parallel (external and internal) joined together by means of floor slabs and transverse beams, with non-ductile characteristics identical to those of the specimens investigated previously by others, and also including lap splices, was developed. In order to investigate the dynamic response of that building, a series of shake table tests with different ground motions were performed. After the first series of tests, the specimen was modified by connecting the spliced reinforcement in the columns in order to capture a different failure mode. Ground motions recorded during seismic events that occurred during the initial period of the experimental campaign (2010) were used in the subsequent experiments. The hierarchy of strengths and sequence of events in the panel zone region were evaluated in an extended version of the bending moment-axial load (M-N) performance domain developed by others. That extension was required due to the asymmetry in the beam cross section introduced by the floor slab. In addition, the effect of the torsion resistance provided by the spandrel (transverse beam) was included. In order to upgrade the brittle and unstable performance of the as-built/repaired specimen, a practical and suitable ad-hoc FRP retrofit intervention was developed, following a partial retrofit strategy that aimed to strengthen exterior beam column joints only (corner and cruciform). The ability of the new FRP scheme to revert the sequence of events in the panel zone region was evaluated using the extended version of the M-N performance domain as well as the guidelines for strengthening plane joints developed by others. Weakening of the floor slab in a novel configuration was also incorporated with the purpose of reducing the flexural capacity of the beam under negative bending moment (slab in tension), enabling the damage relocation from the joint into the beam. The efficacy of the developed retrofit intervention in upgrading the seismic performance of the as-built specimen was investigated using shake table tests with the input motions used in the experiments of the as-built/repaired specimen. Numerical work aimed to predict the response of the model building during the most relevant shake table tests was carried out. By using a simple numerical model with concentrated plasticity elements constructed in Ruaumoko2D, the results of blind and post-experimental predictions of the response of the specimen were addressed. Differences in the predicted response of the building using the nominal and the actual recorded motions of the shake table were investigated. The dependence of the accuracy of the numerical predictions on the assumed values of the parameters that control the hysteresis rules of key structural members was reviewed. During the execution of the experimental campaign part of this thesis, two major earthquakes affected the central part of Chile (27 of February 2010 Maule earthquake) and the Canterbury region in New Zealand (22 February 2011 Canterbury earthquake), respectively. As the author had the opportunity to experience those events and investigate their consequences in structures, the observations related to non-ductile detailing and drawbacks in the state of the practice related to reinforced concrete walls was also addressed in this research, resulting in preliminary recommendations for the refinement of current seismic code provisions and assessment guidelines. The investigations of the ground motions recorded during those and other earthquakes were used to review the procedures related to the input motions used for nonlinear dynamic analysis of buildings as required by most of the current code provisions. Inelastic displacement spectra were constructed using ground motions recorded during the earthquakes mentioned above, in order to investigate the adequacy of modification factors used to obtain reduced design spectra from elastic counterparts. Finally a simplified assessment procedure for RC walls that incorporates capacity compatible spectral demands is proposed.

Videos, UC QuakeStudies

A video of Lianne Dalziel speaking to a public gathering about her reasons for standing for the mayoralty of Christchurch. Dalziel talks about starting her mayoralty where Share an Idea left off, making the Council a high performing team, and getting the community involved in the decisions about the future of the city. The video also includes footage of Dalziel taking a tour of the Christchurch central city. Dalziel visits the ChristChurch Cathedral, pointing out a sign which reads, "The earthquakes stopped us, but inept procedures are killing us". She also visits the new Westende Jewellers building, which she notes was the first rebuild in the Christchurch central city but will come down as part of CERA's Transport Plan. Dalziel is shown socialising with members of the public and watching the Christchurch Wizard bless New Regent Street.

Audio, Radio New Zealand

So what's the Prime Minister Jacinda Ardern got to look forward to when she's back at work? Construction firms falling over, business confidence at a nine-year low, unemployment rising and New Zealand is desperate need of infrastructure to cope with its 10 percent population shock in the last five years. Welcome back Ms Ardern! Ebert Construction is the latest construction company to go belly-up. The Panelists consider why, when the country needs new buildings the most, construction companies aren't making the grade? Peter Silcock of Civil Contractors talks bout the failing of processes and business models used by building firms. Christchurch central seems to have a business micro-climate. And right now it's chilly. The CBD is nothing like it used to be before the 2011 earthquake and those businesses that re-opened say they really had no choice because of the demands of insurance companies. The Kingsland Business Society in Auckland is offering free child minding for couples who go out for the evening in the suburb. United States federal air marshals now follow seemingly ordinary citizens not suspected of a crime, nor on any terrorist watch list. It's a new surveillance programme called "Quiet Skies" and it collects extensive information on travellers based on their behaviour on flights and especailly in airports.

Audio, Radio New Zealand

Tax, water and housing concerns were all debated at length by Bill English and Jacinda Ardern in last night's TVNZ leaders debate. The debate came just an hour after shock 1 News Colmar Brunton poll put Labour out in front. There have been fires and explosions at a flood damaged chemical plant near Houston forcing the evacuation of people in nearby homes. A block of flats in Aro Street has been evacuated after a large slip has come down behind it. After heavy rains and flooding a Mumbai building has collapsed, killing at least 23 people. Biosecurity officials say they expect to decide by the end of the year whether they will need to order the destruction of dairy herds to wipe out a cow disease that's broken out in the South Island. It's been revealed that not a single one of New Zealand's 315 police buildings constructed before 2011 have had a full earthquake safety check. People who've bought houses in Canterbury since the September 2010 earthquake and are still battling with insurance companies over repairs, have been told that if they want to take the matter to court, today is their last chance. The Government has begun urgent talks with Australia over the Queensland's state government's "discriminatory" trade policy which takes effect today. Trade Minister Todd McClay joins us.

Research papers, University of Canterbury Library

Validating dynamic responses of engineered systems subjected to simulated ground motions is essential in scrutinising the applicability of simulated ground motions for engineering demand analyses. This paper compares the responses of two 3D building models subjected to recorded and simulated ground motions scaled to the NZS1170.5 design response spectrum, in order to evaluate the applicability of simulated ground motions for use in conventional engineering practice in New Zealand. The buildings were designed according to the NZS1170.5 and physically constructed in Christchurch prior to the 2010-2011 Canterbury earthquakes. 40 recorded ground motions from the 22 February 2011 Christchurch earthquake, along with the simulated ground motions for this event from Razafindrakoto et al. (2018) are considered. The seismic responses of the structures are principally quantified via the peak floor acceleration and maximum inter-storey drift ratio. Overall, the results indicate a general agreement in seismic demands obtained using the recorded and simulated ensembles of ground motions and provide further evidence that simulated ground motions using state-of-the-art methods can be used in code-based structural performance assessments inplace of, or in combination with, ensembles of recorded ground motions.

Images, eqnz.chch.2010

Damage to the Hotel Grand Chancellor can be seen in the middle. At the bottom left is the lift shaft (now fully demolished) of the CTV building which claimed over 100 lives when it collapsed in the earthquake. Taken during a scenic flight over Christchurch, New Zealand, 3 months after the deadly earthquake of 22 February, 2011. Much of the inn...

Images, eqnz.chch.2010

The current state of the Christchurch Cathedral can be seen in the middle. The spire collapsed as a result of the earthquake. Taken during a scenic flight over Christchurch, New Zealand, 3 months after the deadly earthquake of 22 February, 2011. Much of the inner city CBD is still cordoned off and will be for some time. About 900 buildings are ...

Images, eqnz.chch.2010

20140522_8951_EOS M-22 Demolition Of what many in Christchurch know as the Millers building, but for many recent years was the home to the Christchurch City Council, till just a week or two before the first earthquake of 2010. Now, in mid-2014 it is finally being demolished after nearly 45 months empty. A bus is leaving the new (temporary) bu...

Images, Alexander Turnbull Library

The title is 'Gerry BrownLie?' and the cartoon shows the Minister for Earthquake recovery, Gerry Brownlee, saying 'It was NOT a lie. It was a false promise'. Context: Earthquake Minister Gerry Brownlee has apologised for falsely promising red zone homeowners they would be paid out for improvements to their house. Brownlee promised in June that, in some cases, home improvements like new kitchens would be included in the government settlement offer for red zone houses. But the offer is only valid if the improvement has added to the footprint of the house. (Press - 4 September 2011) Alternate version of DCDL-0018758 Quantity: 1 digital cartoon(s).

Research papers, University of Canterbury Library

Mr Wayne Tobeck, Director of Southrim Group (SRG), sponsored this 2013 MEM Project titled; A Technical and Economic Feasibility Study for the Integration of GSHP Technology in the Christchurch Rebuild. Following the recent Christchurch earthquakes, a significant amount of land has become too unstable to support traditional building foundations. This creates an opportunity to implement new and unique foundation designs previously unconsidered due to high costs compared to traditional methods. One such design proposes that an Injection Micro-Piling technique could be used. This can also be coupled with HVAC technology to create a Ground Source Heat Pump (GSHP) arrangement in both new buildings and as retrofits for building requiring foundation repair. The purpose of this study was to complete a feasibility study on the merits of SRG pursuing this proposed product. A significant market for such a product was found to exist, while the product was also found to be technically and legally feasible. However, the proposed product was found to not be economically feasible with respect to Air Source Heat Pumps due to the significantly higher capital and installation costs required. Further analysis suggests GSHPs may become more economically attractive in operating temperatures lower than -9oC, though the existence of markets with this climate in NZ has not been studied. It is therefore suggested that SRG do not proceed with plans to develop a GSHP coupled foundation solution for the Christchurch rebuild.

Audio, Radio New Zealand

Our programme this morning is completely devoted to the aftermath of yesterday's Christchurch earthquake. Civil Defence says rescue teams in Christchurch are still recovering people alive who have been trapped in buildings in the city overnight. The emergency department at Christchurch Hospital is extremely busy with many seriously injured people. After an emergency cabinet meeting yesterday, the Prime Minister flew to Christchurch to view the aftermath of the quake first hand. Numerous stories, some of survival, others more tragic are emerging in the aftermath of the quake.

Audio, Radio New Zealand

On 31 May, Dr Ann Brower will deliver a lecture at the University of Canterbury, titled: A Little Guy's Guide to Making a Difference after receiving the Critic and Conscience of Society Award earlier this month. Dr Brower is probably best known for her advocacy for more stringent regulation of earthquake-prone buildings, a campaign informed by her experience of being on a bus crushed by falling masonry in Christchurch's 2011 earthquake. Twelve passengers died on or beside the bus. She's also been prominent in highlighting high country land being transferred from Crown to private ownership.

Images, UC QuakeStudies

A damaged brick building on Tuam Street. Bricks have fallen from the wall exposing the interior, where a wooden structure can be seen to have collapsed. The photographer comments, "This is the damage caused by the numerous earthquakes in Christchurch, New Zealand. It closely resembles a face and the round blob in the square hole at the top of the nose is a pigeon".

Images, UC QuakeStudies

A digitally manipulated image of a high-reach excavator demolishing a building. The photographer comments, "After the earthquakes in Christchurch, New Zealand the demolition of most of the City Centre began. After two years the government thought that the progress was far too slow, so began the start of the automatic demolition. Luckily when the solar powered demolition machines started to cause indiscriminate death and destruction they were isolated to the South Island and unable to cross the seas".

Research papers, University of Canterbury Library

Structural pounding may be defined as the collisions occurring between adjacent dynamically excited structures which lack a sufficient separation gap between them. Extensive theoretical and experimental studies have been conducted to investigate this phenomenon. However, the majority, if not all, of these studies fail to consider the flexibility of the soil upon which these structures are constructed. This study aims to investigate the degree of approximation inherent in previous pounding studies which neglected this important feature. In this study, two aspects of soil flexibility effects on dynamic structural response were investigated: the influence of the supporting soil properties on the individual structures (soil-structure interaction) and the through-soil interaction between the foundations of the adjacent structures. Two structural configurations of reinforced concrete moment-resistant frames were considered: the case of two adjacent twelve-storey frames and the pounding of a twelve- and six-storey frames. Four cases of external excitation were investigated: two actual earthquake records applied from two directions each. A nonlinear inelastic dynamic analysis software package developed at the University of Canterbury has been utilized in this study. Suitable numerical models were developed for the through-soil interaction phenomenon and for the structures, which were designed in accordance to the relevant New Zealand design codes. Soilstructure interaction was represented by means of existing models available in the literature. Various separation gaps were provided and the results were compared with the no pounding case. Storey-level impacts only were considered. The pounding response in which soil flexibility was accounted for was compared to the fixed base response for each of the separation gaps incorporated in this study. A high variation in the results was witnessed, indicating the significance of consideration of soil flexibility effects. In addition, the importance of excitation direction was highlighted in this study. The relative storey accelerations were more dependent on the characteristics of the excitation rather than on the magnitudes of the impact forces. Recommendations were proposed which aim towards the generalization of the results of this study.