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Images, UC QuakeStudies

Damage to the north-west corner of the Cathedral of the Blessed Sacrament. The upper part of the corner structure has collapsed. A statue of the Virgin Mary can be seen in a window. The photographer comments, "A bike ride around the CBD. Catholic Cathedral, Barbadoes St".

Images, eqnz.chch.2010

Aftermath of September 4th Earthquake in Canterbury. Shops on Colombo Street in Christchurch. The initial 7.1 quake has been followed by around 1590 aftershocks recorded to date - causing further damage to already weakened structures.

Research papers, University of Canterbury Library

Buildings subject to earthquake shaking will tend to move not only horizontally but also rotate in plan. In-plan rotation is known as “building torsion” and it may occur for a variety of reasons, including stiffness and strength eccentricity and/or torsional effects from ground motions. Methods to consider torsion in structural design standards generally involve analysis of the structure in its elastic state. This is despite the fact that the structural elements can yield, thereby significantly altering the building response and the structural element demands. If demands become too large, the structure may collapse. While a number of studies have been conducted into the behavior of structures considering inelastic building torsion, there appears to be no consensus that one method is better than another and as a result, provisions within current design standards have not adopted recent proposals in the literature. However, the Canterbury Earthquakes Royal Commission recently made the recommendation that provisions to account for inelastic torsional response of buildings be introduced within New Zealand building standards. Consequently, this study examines how and to what extent the torsional response due to system eccentricity may affect the seismic performance of a building and considers what a simple design method should account for. It is concluded that new methods should be simple, be applicable to both the elastic and inelastic range of response, consider bidirectional excitation and include guidance for multi-story systems.

Images, UC QuakeStudies

A photograph of a temporary structure titled Synthesis, which was created by students from CPIT, in partnership with Dance Hall and Soda Bar. Synthesis was part of CityUps - a 'city of the future for one night only', and the main event of FESTA 2014.

Images, UC QuakeStudies

Damage to the front of the Cathedral of the Blessed Sacrament. The upper part of the corner structures have collapsed, and the cross on the roof is on a lean. A statue of the Virgin Mary can be seen in a window. The photographer comments, "A bike ride around the CBD. Catholic Cathedral, Barbadoes St".

Images, UC QuakeStudies

A photograph of the earthquake damage to a building on Armagh Street. The walls of the building have crumbled and the bricks have spilt onto the footpath, exposing the wooden structure beneath. Police tape and road cones have been placed around the building as a cordon.

Images, UC QuakeStudies

A photograph of a temporary, inflatable structure titled Upload, which was created by students from the University of Auckland, in partnership with Chirney Coffee. Upload was part of CityUps - a 'city of the future for one night only', and the main event of FESTA 2014.

Images, UC QuakeStudies

A photograph of a temporary structure titled Equilibrium, which was created by students from the University of Auckland, in partnership with White Elephant Trust. Equilibrium was part of CityUps - a 'city of the future for one night only', and the main event of FESTA 2014.

Images, UC QuakeStudies

A photograph of a temporary structure titled Equilibrium, which was created by students from the University of Auckland, in partnership with White Elephant Trust. Equilibrium was part of CityUps - a 'city of the future for one night only', and the main event of FESTA 2014.

Images, UC QuakeStudies

A photograph of the earthquake damage to the Knox Church on the corner of Bealey Avenue and Victoria Street. The gable walls have crumbled, exposing the wooden structure inside. Wire fencing, road cones and cordon tape have been placed around the building as a cordon.

Images, UC QuakeStudies

A photograph of the earthquake damage to the back of Wharetiki on Colombo Street. The chimney of the house has pulled away from the back wall and collapsed onto the roof below. A wooden structure built up against the house has also pulled away from the wall.

Images, UC QuakeStudies

A photograph of a temporary structure titled CHCH2061, which was created by students from the University of Auckland, in partnership with DJ Jab. CHCH2061 was part of CityUps - a 'city of the future for one night only', and the main event of FESTA 2014.

Research papers, University of Canterbury Library

The 2010-2011 Christchurch earthquakes generated damage in several Reinforced Concrete (RC) buildings, which had RC walls as the principal resistant element against earthquake demand. Despite the agreement between structural engineers and researchers in an overall successfully performance there was a lack of knowledge about the behaviour of the damaged structures, and even deeper about a repaired structure, which triggers arguments between different parties that remains up to these days. Then, it is necessary to understand the capacity of the buildings after the earthquake and see how simple repairs techniques improve the building performance. This study will assess the residual capacity of ductile slender RC walls according to current standards in New Zealand, NZS 3101.1 2006 A3. First, a Repaired RC walls Database is created trying to gather previous studies and to evaluate them with existing international guidelines. Then, an archetype building is designed, and the wall is extracted and scaled. Four half-scale walls were designed and will be constructed and tested at the Structures Testing Laboratory at The University of Auckland. The overall dimensions are 3 [m] height, 2 [m] length and 0.175 [m] thick. All four walls will be identical, with differences in the loading protocol and the presence or absence of a repair technique. Results are going to be useful to assess the residual capacity of a damaged wall compare to the original behaviour and also the repaired capacity of walls with simpler repair techniques. The expected behaviour is focussed on big changes in stiffness, more evident than in previously tested RC beams found in the literature.

Images, UC QuakeStudies

A photograph of a temporary, inflatable structure, titled Upload, being installed for CityUps - a 'city of the future for one night only', and the main event of FESTA 2014. Upload was created by students from the University of Auckland, in partnership with Chirney Coffee.

Images, UC QuakeStudies

A photograph of a temporary structure titled GlowCity being installed for CityUps - a 'city of the future for one night only', and the main event of FESTA 2014. GlowCity was created by students from Unitec, in partnership with Games Hall street games.

Images, UC QuakeStudies

A photograph of a temporary, inflatable structure, titled Upload, which was created by students from the University of Auckland, in partnership with Chirney Coffee. Upload was part of CityUps - a 'city of the future for one night only', and the main event of FESTA 2014.

Images, UC QuakeStudies

A photograph of a temporary structure, titled Continuum, being installed for CityUps - a 'city of the future for one night only', and the main event of FESTA 2014. Continuum was created by students from the University of Auckland, in partnership with Excuse My French Crepe Cart.

Research papers, The University of Auckland Library

The full scale, in-situ investigations of instrumented buildings present an excellent opportunity to observe their dynamic response in as-built environment, which includes all the real physical properties of a structure under study and its surroundings. The recorded responses can be used for better understanding of behavior of structures by extracting their dynamic characteristics. It is significantly valuable to examine the behavior of buildings under different excitation scenarios. The trends in dynamic characteristics, such as modal frequencies and damping ratios, thus developed can provide quantitative data for the variations in the behavior of buildings. Moreover, such studies provide invaluable information for the development and calibration of realistic models for the prediction of seismic response of structures in model updating and structural health monitoring studies. This thesis comprises two parts. The first part presents an evaluation of seismic responses of two instrumented three storey RC buildings under a selection of 50 earthquakes and behavioral changes after Ms=7.1 Darfield (2010) and Ms=6.3 Christchurch (2011) earthquakes for an instrumented eight story RC building. The dynamic characteristics of the instrumented buildings were identified using state-of-the-art N4SID system identification technique. Seismic response trends were developed for the three storey instrumented buildings in light of the identified frequencies and the peak response accelerations (PRA). Frequencies were observed to decrease with excitation level while no trends are discernible for the damping ratios. Soil-structure interaction (SSI) effects were also determined to ascertain their contribution in the seismic response. For the eight storey building, it was found through system identification that strong nonlinearities in the structural response occurred and manifested themselves in all identified natural frequencies of the building that exhibited a marked decrease during the strong motion duration compared to the pre-Darfield earthquakes. Evidence of foundation rocking was also found that led to a slight decrease in the identified modal frequencies. Permanent stiffness loss was also observed after the strong motion events. The second part constitutes developing and calibrating finite element model (FEM) of the instrumented three storey RC building with a shear core. A three dimensional FEM of the building is developed in stages to analyze the effect of structural, non-structural components (NSCs) and SSI on the building dynamics. Further to accurately replicate the response of the building following the response trends developed in the first part of the thesis, sensitivity based model updating technique was applied. The FEMs were calibrated by tuning the updating parameters which are stiffnesses of concrete, NSCs and soil. The updating parameters were found to generally follow decreasing trends with the excitation level. Finally, the updated FEM was used in time history analyses to assess the building seismic performance at the serviceability limit state shaking. Overall, this research will contribute towards better understanding and prediction of the behavior of structures subjected to ground motion.

Images, UC QuakeStudies

A photograph of a temporary structure, titled Continuum, being installed for CityUps. CityUps was a 'city of the future for one night only', and the main event of FESTA 2014. Continuum was created by students from the University of Auckland, in partnership with Excuse My French Crepe Cart.

Articles, UC QuakeStudies

A PDF copy of the site map for CityUps. CityUps was a 'city of the future for one night only', and the main event of FESTA 2014. It was held on vacant sites at the intersection of Lichfield Street, Manchester Street and High Street. Architecture students from Unitec, The University of Auckland and CPIT collaborated with local businesses to create large-scale, temporary structures to entertain the public.

Research papers, University of Canterbury Library

Earthquake-triggered soil liquefaction caused extensive damage and heavy economic losses in Christchurch during the 2010-2011 Canterbury earthquakes. The most severe manifestations of liquefaction were associated with the presence of natural deposits of clean sands and silty sands of fluvial origin. However, liquefaction resistance of fines-containing sands is commonly inferred from empirical relationships based on clean sands (i.e. sands with less than 5% fines). Hence, existing evaluation methods have poor accuracy when applied to silty sands. Also, existing methods do not quantify appropriately the influence on liquefaction resistance of soil fabric and structure, which are unique to a specific depositional environment. This study looks at the influence of fines content, soil fabric (i.e. arrangement of soil particles) and structure (e.g. layering, segregation) on the undrained cyclic behaviour and liquefaction resistance of fines-containing sandy soils from Christchurch using Direct Simple Shear (DSS) tests on soil specimens reconstituted in the laboratory with the water sedimentation technique. The poster describes experimental procedures and presents early test results on two sands retrieved at two different sites in Christchurch.

Images, UC QuakeStudies

A photograph of the Durham Street Methodist Church on Durham Street. The church has almost completely collapsed and only a small section of the structure is still standing. Masonry and other rubble has spilled onto the footpath and street in front. To the right a plywood sign has been propped against the front fence. USAR codes have been spray-painted on the sign.

Images, UC QuakeStudies

A photograph looking south down Colombo Street from the intersection of Gloucester Street. In the distance a crane is hanging over Cathedral Square. Below the crane is a pile of rubble from the partially-demolished tower of ChristChurch Cathedral. To the right is a smaller crane and a steel structure which will be used to brace the front of the Cathedral.

Audio, UC QuakeStudies

An audio recording of a mayoral debate hosted by Generation Zero in partnership with 350 Christchurch. The event was titled Mayoral Debate: a climate-smart Christchurch. It was held on campus at the University of Canterbury on Thursday 22 September, 2016 and was moderated by Catarina Gutierrez of the Ministry of Awesome. The debate was structured as follows: Section 1: Candidates answered set questions sent prior to the event Section 2: Candidates answered set questions they have not seen before Interval Section 3: Candidates answered written questions from the audience (climate-related questions were submitted during the interval and a selection of these were given to the moderator). The audio recording was taken through the University's Echo system.

Research papers, University of Canterbury Library

In 2010 and 2011 a series of earthquakes hit the central region of Canterbury, New Zealand, triggering widespread and damaging liquefaction in the area of Christchurch. Liquefaction occurred in natural clean sand deposits, but also in silty (fines-containing) sand deposits of fluvial origin. Comprehensive research efforts have been subsequently undertaken to identify key factors that influenced liquefaction triggering and severity of its manifestation. This research aims at evaluating the effects of fines content, fabric and layered structure on the cyclic undrained response of silty soils from Christchurch using Direct Simple Shear (DSS) tests. This poster outlines preliminary calibration and verification DSS tests performed on a clean sand to ensure reliability of testing procedures before these are applied to Christchurch soils.

Research papers, The University of Auckland Library

This thesis presents an assessment of historic seismic performance of the New Zealand stopbank network from the 1968 Inangahua earthquake through to the 2016 Kaikōura earthquake. An overview of the types of stopbanks and the main aspects of the design and construction of earthen stopbanks was presented. Stopbanks are structures that are widely used on the banks of rivers and other water bodies to protect against the impact of flood events. Earthen stopbanks are found to be the most used for such protection measures. Different stopbank damage or failure modes that may occur due to flooding or earthquake excitation were assessed with a focus on past earthquakes internationally, and examples of these damage and failure modes were presented. Stopbank damage and assessment reports were collated from available reconnaissance literature to develop the first geospatial database of stopbank damage observed in past earthquakes in New Zealand. Damage was observed in four earthquakes over the past 50 years, with a number of earthquakes resulting in no stopbank damage. The damage database therefore focussed on the Edgecumbe, Darfield, Christchurch and Kaikōura earthquakes. Cracking of the crest and liquefaction-induced settlement were the most common forms of damage observed. To understand the seismic demand on the stopbank network in past earthquakes, geospatial analyses were undertaken to approximate the peak ground acceleration (PGA) across the stopbank network for ten large earthquakes that have occurred in New Zealand over the past 50 years. The relationship between the demand, represented by the peak ground acceleration (PGA) and damage is discussed and key trends identified. Comparison of the seismic demand and the distribution of damage suggested that the seismic performance of the New Zealand stopbank network has been generally good across all events considered. Although a significant length of the stopbank networks were exposed to high levels of shaking in past events, the overall damage length was a small percentage of this. The key aspect controlling performance was the performance of the underlying foundation soils and the effect of this on the stopbank structure and stability.

Research papers, University of Canterbury Library

Hybrid broadband simulation methods typically compute high-frequency portion of ground-motions using a simplified-physics approach (commonly known as “stochastic method”) using the same 1D velocity profile, anelastic attenuation profile and site-attenuation (κ0) value for all sites. However, these parameters relating to Earth structure are known to vary spatially. In this study we modify this conventional approach for high-frequency ground-shaking by using site-specific input parameters (referred to as “site-specific”) and analyze improvements over using same parameters for all sites (referred to as “generic”). First, we theoretically understand how different 1D velocity profiles, anelastic attenuation profiles and site-attenuation (κ0) values affects the Fourier Acceleration Spectrum (FAS). Then, we apply site-specific method to simulate 10 events from the 2010-2011 Canterbury earthquake sequence to assess performance against the generic approach in predicting recorded ground-motions. Our initial results suggest that the site-specific method yields a lower simulation standard deviation than generic case.