The city of Christchurch has experienced over 10,000 aftershocks since the 4th of September 2010 earthquake of which approximately 50 have been greater than magnitude 5. The damage caused to URM buildings in Christchurch over this sequence of earthquakes has been well documented. Due to the similarity in age and construction of URM buildings in Adelaide, South Australia and Christchurch (they are sister cities, of similar age and heritage), an investigation was conducted to learn lessons for Adelaide based on the Christchurch experience. To this end, the number of URM buildings in the central business districts of both cities, the extent of seismic strengthening that exists in both cities, and the relative earthquake hazards for both cities were considered. This paper will report on these findings and recommend strategies that the city of Adelaide could consider to significantly reduce the seismic risk posed by URM buildings in future earthquake
This thesis revisits the topic of earthquake recovery in Christchurch City more than a decade after the Canterbury earthquakes. Despite promising visions of a community reconnected and a sustainable and liveable city, significant portions of the city’s core – the Red Zone – remain dilapidated and “eerily empty”. At the same time, new developments in other areas have proven to be alienated or underutilised. Currently, the Canterbury Earthquake Recovery Authority’s plans for the rebuilding highlight the delivery of more residential housing to re-populate the city centre. However, prevalent approaches to housing development in Christchurch are ineffective for building an inclusive and active community. Hence, the central inquiry of the thesis is how the development of housing complexes can revitalise the Red Zone within the Christchurch city centre. The inquiry has been carried out through a research-through-design methodology, recognising the importance of an in-depth investigation that is contextualised and combined with the intuition and embodied knowledge of the designer. The investigation focuses on a neglected site in the Red Zone in the heart of Christchurch city, with significant Victorian and Edwardian Baroque heritage buildings, including Odeon Theatre, Lawrie & Wilson Auctioneers, and Sol Square, owned by The Regional Council Environment Canterbury. The design inquiry argues, develops, and is carried through a place-assemblage lens to housing development for city recovery, which recognizes the significance of socially responsive architecture that explores urban renewal by forging connections within the social network. Therefore, place-assemblage criteria and methods for developing socially active and meaningful housing developments are identified. Firstly, this thesis argues that co-living housing models are more focused on people relations and collective identity than the dominant developer-driven housing rebuilds, as they prioritise conduits for interaction and shared social meaning and practices. Secondly, the adaptive reuse of derelict heritage structures is proposed to reinvigorate the urban fabric, as heritage is seen to be conceived as and from a social assemblage of people. The design is realised by the principles outlined in the ICOMOS charter, which involves incorporating the material histories of existing structures and preserving the intangible heritage of the site by ensuring the continuity of cultural practices. Lastly, design processes and methods are also vital for place-sensitive results, which pay attention to the site’s unique characteristics to engage with local stakeholders and communities. The research explores place-assemblage methods of photographic extraction, the drawing of story maps, precedent studies, assemblage maps, bricolages, and paper models, which show an assembly of layers that piece together the existing heritage, social conduits, urban commons and housing to conceptualise the social network within its place
Predictive modelling provides an efficient means to analyse the coastal environment and generate knowledge for long term urban planning. In this study, the numerical models SWAN and XBeach were incorporated into the ESRI ArcGIS interface by means of the BeachMMtool. This was applied to the Greater Christchurch coastal environment to simulate geomorphological evolution through hydrodynamic forcing. Simulations were performed using the recent sea level rise predictions by the Intergovernmental Panel on Climate Change (2013) to determine whether the statutory requirements outlined in the New Zealand Coastal Policy Statement 2010 are consistent with central, regional and district designations. Our results indicate that current land use zoning in Greater Christchurch is not consistent with these predictions. This is because coastal hazard risk has not been thoroughly quantified during the process of installing the Canterbury Earthquake Recovery Authority residential red zone. However, the Christchurch City Council’s flood management area does provide an extent to which managed coastal retreat is a real option. The results of this research suggest that progradation will continue to occur along the Christchurch foreshore due to the net sediment flux retaining an onshore direction and the current hydrodynamic activity not being strong enough to move sediment offshore. However, inundation during periods of storm surge poses a risk to human habitation on low lying areas around the Avon-Heathcote Estuary and the Brooklands lagoon
A dramatic consequence of the Christchurch, New Zealand, earthquakes of 2010 and 2011 was the widespread liquefaction in the city. Part of the central business district (CBD) was badly affected by liquefaction but elsewhere large volumes of ejecta were not evident for those parts of the CBD where the upper layers in the soil profile are sandy gravel and gravelly sand. The purpose of the paper is to investigate the effect of the gravel permeability on the rise and dissipation of excess pore water pressure during cyclic loading of a soil profile idealised from Christchurch data. The Cyclic1D software, which performs one-dimensional non-linear effective stress site response analysis, was used. Permeability values associated with gravel were found to suppress the cyclic accumulation of excess pore water pressure in gravel layers. Given that there has not been any systematic measurement of the in situ permeability of the gravels in Christchurch, the modelling in the paper suggests that likely values for the bulk permeability of the gravel layers are within the range suggested in the geotechnical literature. However, the work reported is of wider application than Christchurch and emphasises the controlling influence of permeability on the accumulation and dissipation of cyclic pore pressures VoR - Version of Record
The Manchester Courts building was a heritage building located in central Christchurch (New Zealand) that was damaged in the Mw 7.1 Darfield earthquake on 4 September 2010 and subsequently demolished as a risk reduction exercise. Because the building was heritage listed, the decision to demolish the building resulted in strong objections from heritage supporters who were of the opinion that the building had sufficient residual strength to survive possible aftershock earthquakes. On 22 February 2011 Christchurch was struck by a severe aftershock, leading to the question of whether building demolition had proven to be the correct risk reduction strategy. Finite element analysis was used to undertake a performance-based assessment, validating the accuracy of the model using the damage observed in the building before its collapse. In addition, soil-structure interaction was introduced into the research due to the comparatively low shear wave velocity of the soil. The demolition of a landmark heritage building was a tragedy that Christchurch will never recover from, but the decision was made considering safety, societal, economic and psychological aspects in order to protect the city and its citizens. The analytical results suggest that the Manchester Courts building would have collapsed during the 2011 Christchurch earthquake, and that the collapse of the building would have resulted in significant fatalities
