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Research papers, University of Canterbury Library

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

Research papers, University of Canterbury Library

Beach ridge stratigraphy can provide an important record of both sustained coastal progradation and responses to events such as extreme storms, as well as evidence of earthquake induced sediment pulses. This study is a stratigraphic investigation of the late Holocene mixed sand gravel (MSG) beach ridge plain on the Canterbury coast, New Zealand. The subsurface was imaged along a 370 m shore-normal transect using 100 and 200 MHz ground penetrating radar (GPR) antennae, and cored to sample sediment textures. Results show that, seaward of a back-barrier lagoon, the Pegasus Bay beach ridge plain prograded almost uniformly, under conditions of relatively stable sea level. Nearshore sediment supply appears to have created a sustained sediment surplus, perhaps as a result of post-seismic sediment pulses, resulting in a flat, morphologically featureless beach ridge plain. Evidence of a high magnitude storm provides an exception, with an estimated event return period in excess of 100 years. Evidence from the GPR sequence combined with modern process observations from MSG beaches indicates that a paleo storm initially created a washover fan into the back-barrier lagoon, with a large amount of sediment simultaneously moved off the beach face into the nearshore. This erosion event resulted in a topographic depression still evident today. In the subsequent recovery period, sediment was reworked by swash onto the beach as a sequence of berm deposit laminations, creating an elevated beach ridge that also has a modern-day topographic signature. As sediment supply returned to normal, and under conditions of falling sea level, a beach ridge progradation sequence accumulated seaward of the storm feature out to the modern-day beach as a large flat, uniform progradation plain. This study highlights the importance of extreme storm events and earthquake pulses on MSG coastlines in triggering high volume beach ridge formation during the subsequent recovery period.

Research papers, University of Canterbury Library

Timber has experienced renewed interests as a sustainable building material in recent times. Although traditionally it has been the prime choice for residential construction in New Zealand and some other parts of the world, its use can be increased significantly in the future through a wider range of applications, particularly when adopting engineered wood material, Research has been started on the development of innovative solutions for multi-storey non-residential timber buildings in recent years and this study is part of that initiative. Application of timber in commercial and office spaces posed some challenges with requirements of large column-free spaces. The current construction practice with timber is not properly suited for structures with the aforementioned required characteristics and new type of structures has to be developed for this type of applications. Any new structural system has to have adequate capacity for carry the gravity and lateral loads due to occupancy and the environmental effects. Along with wind loading, one of the major sources of lateral loads is earthquakes. New Zealand, being located in a seismically active region, has significant risk of earthquake hazard specially in the central region of the country and any structure has be designed for the seismic loading appropriate for the locality. There have been some significant developments in precast concrete in terms of solutions for earthquake resistant structures in the last decade. The “Hybrid” concept combining post-tensioning and energy dissipating elements with structural members has been introduced in the late 1990s by the precast concrete industry to achieve moment-resistant connections based on dry jointed ductile connections. Recent research at the University of Canterbury has shown that the concept can be adopted for timber for similar applications. Hybrid timber frames using post-tensioned beams and dissipaters have the potential to allow longer spans and smaller cross sections than other forms of solid timber frames. Buildings with post-tensioned frames and walls can have larger column-free spaces which is a particular advantage for non-residential applications. While other researchers are focusing on whole structural systems, this research concentrated on the analysis and design of individual members and connections between members or between member and foundation. This thesis extends existing knowledge on the seismic behaviour and response of post-tensioned single walls, columns under uni-direction loads and small scale beam-column joint connections into the response and design of post-tensioned coupled walls, columns under bi-directional loading and full-scale beam-column joints, as well as to generate further insight into practical applications of the design concept for subassemblies. Extensive experimental investigation of walls, column and beam-column joints provided valuable confirmation of the satisfactory performance of these systems. In general, they all exhibited almost complete re-centering capacity and significant energy dissipation, without resulting into structural damage. The different configurations tested also demonstrated the flexibility in design and possibilities for applications in practical structures. Based on the experimental results, numerical models were developed and refined from previous literature in precast concrete jointed ductile connections to predict the behaviour of post-tensioned timber subassemblies. The calibrated models also suggest the values of relevant parameters for applications in further analysis and design. Section analyses involving those parameters are performed to develop procedures to calculate moment capacities of the subassemblies. The typical features and geometric configurations the different types of subassemblies are similar with the only major difference in the connection interfaces. With adoption of appropriate values representing the corresponding connection interface and incorporation of the details of geometry and configurations, moment capacities of all the subassemblies can be calculated with the same scheme. That is found to be true for both post-tensioned-only and hybrid specimens and also applied for both uni-directional and bi-directional loading. The common section analysis and moment capacity calculation procedure is applied in the general design approach for subassemblies.

Images, UC QuakeStudies

A photograph of Dr Lucy D'Aeth, Public Health Specialist for All Right?, taking part in #FiveYearsOn. Lucy holds a sign which reads, "Five years on, I feel... ...tired, but I still love Chch. Lucy Beckenham." All Right? posted the photograph on their Facebook Timeline on 21 February 2016 at 9:12am. All Right? captioned the photograph. "Lucy from Healthy Christchurch is feeling tired, but she still loves Chch!! #fiveyears on #5yearson #allrightnz".

Research papers, University of Canterbury Library

In this paper Paul Millar outlines the development of the University of Canterbury Quakebox project, a collaborative venture between the UC CEISMIC Canterbury Earthquakes Digital Archive and the New Zealand Institute of Language Brain and Behaviour to preserve people’s earthquake stories for the purposes of research, teaching and commemoration. The project collected over 700 stories on high definition video, and Millar is now looking at using the corpus to underpin a longitudinal study of post-quake experience.

Images, Alexander Turnbull Library

The cartoon shows Christchurch mayor Bob Parker and his wife in bed. Bob Parker's wife says 'Bob darling, the chances of a news crew bursting in here at this time of night are virtually nil, so please take that bloody jacket off...' Context - Bob Parker, it is true, seems to be wearing the same trendy orange and black 'site manager's jacket for the very many photo opportunities afforded post earthquake of 22 February 2011. Quantity: 1 digital cartoon(s).

Images, UC QuakeStudies

An image suggesting how watching the Cricket World Cup Final can be an opportunity to take notice. The image suggests being proud considering the journey the Black Caps have taken to get to the final. The image is from the 'World Cup Final Survival Guide' which depicted ways to practice the Five Ways to Wellbeing while watching the match. All Right? posted the image on their Facebook page on 27 March 2015 at 3:19pm.

Images, UC QuakeStudies

A photograph of two people from BECA at the Winter Survival Kit launch at Shirley Intermediate School. In the background are the 'All Righties' and Ciaran Fox from All Right?. All Right? posted the photograph on their Facebook Timeline on 25 July 2014 at 4:02pm. The Facebook image is captioned, "All paid for by the wonderful people at BECA... who collected money from their staff around the world after the February earthquake. Good people.

Images, UC QuakeStudies

A photograph of Ciaran Fox, Mental Health Promoter for All Right?, taking part in #FiveYearsOn. Fox holds a sign which reads, "Five years on I feel... Proud, hopeful// less tired, less angry// Ciaran, Lyttelton." All Right? posted the photograph on their Facebook Timeline on 21 February at 9:11am. All Right? captioned the photograph. "Lyttelton's Ciaran from All Right? is feeling proud, hopeful, less tired and less angry. #fiveyears on #5yearson #allrightnz".

Articles, UC QuakeStudies

A PDF copy of a poster created with the All Right? Poster Generator. The poster features the responses from a number of Christchurch residents about what makes them feel good, such as "Walking up Harry Ell makes everything all right. Alana, Cashmere." The posters were placed around the city at locations such as cafes, doctors surgeries and fish and chip shops. All Right? posted this poster on their Facebook Timeline on 10 May 2013 at 4:07pm.

Articles, UC QuakeStudies

A PDF copy of a poster like those created on the All Right? Poster Generator. The poster features the responses from a number of Christchurch residents about what makes them feel good, such as "Talking to my friends. Tatiana (11), Woolston." The posters were placed around the city at locations such as cafes, doctors surgeries and fish and chip shops. All Right? posted this poster on their Facebook Timeline on 10 May 2013 at 4:06pm.

Articles, UC QuakeStudies

A PDF copy of two draft images created for the Hanmer Springs competition. Both images read, "Win a Hanmer Springs getaway! We have a Family Escape ($419) or Pamper Pack ($329) to give away, along with eight Mini-Group passes to the hot pools. To be in to win, simply visit fb.com/allrightnz and post a photo of something that makes you feel all right in winter. Entries close at 5pm on Thursday 21 August".

Images, UC QuakeStudies

A man reads a sign posted on the door of the Christchurch Art Gallery, which reads "The gallery is currently closed to the public". The photographer comments, "Red Carded - A red-coloured card shown by a referee to a player, especially in soccer, to indicate that the player is being ejected from the pitch. The Christchurch Art Gallery has left the building. All the current and future exhibitions of the Art Gallery are being mainly held out of doors".

Videos, UC QuakeStudies

A video of Adam McGrath, Jess Shanks and Alice Ryan Williams from Lyttelton band The Eastern singing songs to people in the community. The song recipients were nominated by family, friends or workmates, and in total seven people were chosen, including a teacher, office worker and traffic controller. The video and event were organised by All Right?. The video was distributed by The Press and was posted to the All Right? Facebook Timeline in October 2014.

Images, UC QuakeStudies

An image used as a profile picture on the All Right? Facebook page. The image reads, "All Right? Winter Photo Competition. Win dinner at Roots Restaurant! Share a picture of what's making you feel All Right this winter and be in to win a five course meal for two (worth $150!) at Roots, Lyttelton's hot new restaurant." The image was also posted by All Right? to their Facebook Timeline on 30 July 2013 at 9:18am.

Images, UC QuakeStudies

A car stuck in a large pothole on River Road. The wheels on the right hand side of the car have fallen into the hole, leaving the car grounded against the road surface. The photographer comments, "This car belonged to a postal delivery worker - the NZ Post bike rack is mounted on the towbar. The owner must have biked home. Later a tow truck arrived to extract the car from the hole that had opened under its front wheel".

Research papers, University of Canterbury Library

Liquefaction during the 4th September 2010 Mw 7.1 Darfield earthquake and large aftershocks in 2011 (Canterbury earthquake sequence, CES) caused severe damage to land and infrastructure within Christchurch, New Zealand. Approximately one third of the total CES-induced financial losses were directly attributable to liq- uefaction and thus highlights the need for local and regional authorities to assess liquefaction hazards for present and future developments. This thesis is the first to conduct paleo-liquefaction studies in eastern Christchurch for the purpose of de- termining approximate return times of liquefaction-inducing earthquakes within the region. The research uncovered evidence for pre-CES liquefaction dated by radiocarbon and cross-cutting relationships as post-1660 to pre-1905. Additional paleo-liquefaction investigations within the eastern Christchurch suburb of Avon- dale, and the northern township of Kaiapoi, revealed further evidence for pre-CES liquefaction. Pre-CES liquefaction in Avondale is dated as post-1321 and pre-1901, while the Kaiapoi features likely formed during three distinct episodes: post-1458 and possibly during the 1901 Cheviot earthquake, post-1297 to pre-1901, and pre-1458. Evaluation of the liquefaction potential of active faults within the Can- terbury region indicates that many faults have the potential to cause widespread liquefaction within Avondale and Kaiapoi. The identification of pre-CES liquefac- tion confirms that these areas have previously liquefied, and indicates that residen- tial development in eastern Christchurch between 1860 and 2005 occurred in areas containing geologic evidence for pre-CES liquefaction. Additionally, on the basis of detailed field and GIS-based mapping and geospatial-statistical analysis, the distribution and severity of liquefaction and lateral spreading within the eastern Christchurch suburb of Avonside is shown in this study to be strongly in uenced by geomorphic and topographic variability. This variability is not currently ac- counted for in site-specific liquefaction assessments nor the simplified horizontal displacement models, and accounts for some of the variability between the pre- dicted horizontal displacements and those observed during the CES. This thesis highlights the potential applications of paleo-liquefaction investigations and ge- omorphic mapping to seismic and liquefaction hazard assessments and may aid future land-use planning decisions.

Research papers, The University of Auckland Library

This thesis presents the application of data science techniques, especially machine learning, for the development of seismic damage and loss prediction models for residential buildings. Current post-earthquake building damage evaluation forms are developed for a particular country in mind. The lack of consistency hinders the comparison of building damage between different regions. A new paper form has been developed to address the need for a global universal methodology for post-earthquake building damage assessment. The form was successfully trialled in the street ‘La Morena’ in Mexico City following the 2017 Puebla earthquake. Aside from developing a framework for better input data for performance based earthquake engineering, this project also extended current techniques to derive insights from post-earthquake observations. Machine learning (ML) was applied to seismic damage data of residential buildings in Mexico City following the 2017 Puebla earthquake and in Christchurch following the 2010-2011 Canterbury earthquake sequence (CES). The experience showcased that it is readily possible to develop empirical data only driven models that can successfully identify key damage drivers and hidden underlying correlations without prior engineering knowledge. With adequate maintenance, such models have the potential to be rapidly and easily updated to allow improved damage and loss prediction accuracy and greater ability for models to be generalised. For ML models developed for the key events of the CES, the model trained using data from the 22 February 2011 event generalised the best for loss prediction. This is thought to be because of the large number of instances available for this event and the relatively limited class imbalance between the categories of the target attribute. For the CES, ML highlighted the importance of peak ground acceleration (PGA), building age, building size, liquefaction occurrence, and soil conditions as main factors which affected the losses in residential buildings in Christchurch. ML also highlighted the influence of liquefaction on the buildings losses related to the 22 February 2011 event. Further to the ML model development, the application of post-hoc methodologies was shown to be an effective way to derive insights for ML algorithms that are not intrinsically interpretable. Overall, these provide a basis for the development of ‘greybox’ ML models.