It is interesting to consider how we are influenced by an intangible map of our senses and emotions tied to our place in the world. We pay little attention to how we feel walking around a familiar neighbourhood, looking at … Continue reading →
Unreinforced masonry (URM) cavity-wall construction is a form of masonry where two leaves of clay brick masonry are separated by a continuous air cavity and are interconnected using some form of tie system. A brief historical introduction is followed by details of a survey undertaken to determine the prevalence of URM cavity-wall buildings in New Zealand. Following the 2010/2011 Canterbury earthquakes it was observed that URM cavity-walls generally suffered irreparable damage due to a lack of effective wall restraint and deficient cavity-tie connections, combined with weak mortar strength. It was found that the original cavity-ties were typically corroded due to moisture ingress, resulting in decreased lateral loadbearing capacity of the cavity-walls. Using photographic data pertaining to Christchurch URM buildings that were obtained during post-earthquake reconnaissance, 252 cavity-walls were identified and utilised to study typical construction details and seismic performance. The majority (72%, 182) of the observed damage to URM cavity-wall construction was a result of out-of-plane type wall failures. Three types of out-of-plane wall failure were recognised: (1) overturning response, (2) one-way bending, and (3) two-way bending. In-plane damage was less widely observed (28%) and commonly included diagonal shear cracking through mortar bed joints or bricks. The collected data was used to develop an overview of the most commonly-encountered construction details and to identify typical deficiencies in earthquake response that can be addressed via the selection and implementation of appropriate mitigation interventions. http://www.journals.elsevier.com/structures
A video of a presentation by Dr Scott Miles during the Community Resilience Stream of the 2016 People in Disasters Conference. The presentation is titled, "A Community Wellbeing Centric Approach to Disaster Resilience".The abstract for this presentation reads as follows: A higher bar for advancing community disaster resilience can be set by conducting research and developing capacity-building initiatives that are based on understanding and monitoring community wellbeing. This presentation jumps off from this view, arguing that wellbeing is the most important concept for improving the disaster resilience of communities. The presentation uses examples from the 2010 and 2011 Canterbury earthquakes to illustrate the need and effectiveness of a wellbeing-centric approach. While wellbeing has been integrated in the Canterbury recovery process, community wellbeing and resilience need to guide research and planning. The presentation unpacks wellbeing in order to synthesize it with other concepts that are relevant to community disaster resilience. Conceptualizing wellbeing as either the opportunity for or achievement of affiliation, autonomy, health, material needs, satisfaction, and security is common and relatively accepted across non-disaster fields. These six variables can be systematically linked to fundamental elements of resilience. The wellbeing variables are subject to potential loss, recovery, and adaptation based on the empirically established ties to community identity, such as sense of place. Variables of community identity are what translate the disruption, damage, restoration, reconstruction, and reconfiguration of a community's different critical services and capital resources to different states of wellbeing across a community that has been impacted by a hazard event. With reference to empirical research and the Canterbury case study, the presentation integrates these insights into a robust framework to facilitate meeting the challenge of raising the standard of community disaster resilience research and capacity building through development of wellbeing-centric approaches.
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.