The sequence of earthquakes that has affected Christchurch and Canterbury since September 2010 has caused damage to a great number of buildings of all construction types. Following post-event damage surveys performed between April 2011 and June 2011, the damage suffered by unreinforced stone masonry buildings is reported and different types of observed failures are described. A detailed technical description of the most prevalently observed failure mechanisms is provided, with reference to recognised failure modes for unreinforced masonry structures. The observed performance of existing seismic retrofit interventions is also provided, as an understanding of the seismic response of these interventions is of fundamental importance for assessing the vulnerability of similar strengthening techniques when applied to unreinforced stone masonry structures.
A video of an address by Peter Davie, Chief Executive of Lyttelton Port Company, at the 2012 Seismics and the City forum. The talk is about how, in today's technological and economic environment, the ability to prevent, prepare for, or quickly recover from a disaster is a critical success factor. The seismic simulations that the Port of Lyttelton ran as part of its long term development plan became a key part of the Port's emergency response, and meant that cargo kept flowing with minimal downtime.
This paper examines the consistency of seismicity and ground motion models, used for seismic hazard analysis in New Zealand, with the observations in the Canterbury earthquakes. An overview is first given of seismicity and ground motion modelling as inputs of probabilistic seismic hazard analysis, whose results form the basis for elastic response spectra in NZS1170.5:2004. The magnitude of earthquakes in the Canterbury earthquake sequence are adequately allowed for in the current NZ seismicity model, however the consideration of ‘background’ earthquakes as point sources at a minimum depth of 10km results in up to a 60% underestimation of the ground motions that such events produce. The ground motion model used in conventional NZ seismic hazard analysis is shown to provide biased predictions of response spectra (over-prediction near T=0.2s , and under-predictions at moderate-to-large vibration periods). Improved ground motion prediction can be achieved using more recent NZ-specific models.
A video of an address by Jim Boult, Chief Executive of Christchurch International Airport Ltd, at the 2012 Seismics and the City forum. The talk covers the major challenge of keeping Christchurch International Airport open since 4 September 2010, and explores the role of the airport in the changed business and tourism environment.
A video of an address by John Vale, Chief Executive of Vynco, at the 2012 Seismics and the City forum. The talk covers how business continuity planning proved to be crucial to the Vynco's survival, and how the company's employees were able to work in new ways to keep export channels open and flowing.
The objective of this project is to collect perishable seismic response data from the baseisolated Christchurch Women's Hospital. The strong and continuing sequence of aftershocks presents a unique opportunity to capture high-fidelity data from a modern base-isolated facility. These measurements will provide quantitative information required to assess the mechanisms at play in this and in many other seismically-isolated structures.
A video of the first part of an address by Dr. John Vargo from the UC branch of Resilient Organisations, at the 2012 Seismics and the City forum. The talk covers case studies from the Canterbury Earthquakes, which shed light on the ingredients of a resilient organisational culture and best business practices for enhancing resilience.
A video of the second part of an address by Dr. John Vargo from the UC branch of Resilient Organisations, at the 2012 Seismics and the City forum. The talk covers case studies from the Canterbury Earthquakes, which shed light on the ingredients of a resilient organisational culture and best business practices for enhancing resilience.
A video of the first part of a series of talks on the topic of Planning and People, at the 2012 Seismics and the City forum. The talks are as follows: Mary Devine, Managing Director of Ballantyne and Co, on Anchoring Re:START and holding the centre; Anthony Leighs, Chief Executive of Leighs Construction, on Deconstruction and Reconstruction; and Sam Johnson, founder of the Student Volunteer Army, on Mobilising a Quick Response.
A video of the second part of a series of talks on the topic of Planning and People, at the 2012 Seismics and the City forum. The talks are as follows: Mary Devine, Managing Director of Ballantyne and Co, on Anchoring Re:START and holding the centre; Anthony Leighs, Chief Executive of Leighs Construction, on Deconstruction and Reconstruction; and Sam Johnson, founder of the Student Volunteer Army, on Mobilising a Quick Response
A video of the first part of an address by Roger Sutton, Chief Executive of Canterbury Earthquake Recovery Authority, at the 2012 Seismics and the City forum. The talk focuses on Sutton's roles as the CEO of Orion during the September and February earthquakes, and the co-ordinator of the recovery and rebuild of Christchurch.
A video of the second part of an address by Roger Sutton, Chief Executive of Canterbury Earthquake Recovery Authority, at the 2012 Seismics and the City forum. The talk focuses on Sutton's roles as the CEO of Orion during the September and February earthquakes, and the co-ordinator of the recovery and rebuild of Christchurch.
Previous earthquakes demonstrated destructive effects of soil-structure interaction on structural response. For example, in the 1970 Gediz earthquake in Turkey, part of a factory was demolished in a town 135 km from the epicentre, while no other buildings in the town were damaged. Subsequent investigations revealed that the fundamental period of vibration of the factory was approximately equal to that of the underlying soil. This alignment provided a resonance effect and led to collapse of the structure. Another dramatic example took place in Adapazari, during the 1999 Kocaeli earthquake where several foundations failed due to either bearing capacity exceedance or foundation uplifting, consequently, damaging the structure. Finally, the Christchurch 2012 earthquakes have shown that significant nonlinear action in the soil and soil-foundation interface can be expected due to high levels of seismic excitation and spectral acceleration. This nonlinearity, in turn, significantly influenced the response of the structure interacting with the soil-foundation underneath. Extensive research over more than 35 years has focused on the subject of seismic soil-structure interaction. However, since the response of soil-structure systems to seismic forces is extremely complex, burdened by uncertainties in system parameters and variability in ground motions, the role of soil-structure interaction on the structural response is still controversial. Conventional design procedures suggest that soil-structure interaction effects on the structural response can be conservatively ignored. However, more recent studies show that soil-structure interaction can be either beneficial or detrimental, depending on the soil-structure-earthquake scenarios considered. In view of the above mentioned issues, this research aims to utilise a comprehensive and systematic probabilistic methodology, as the most rational way, to quantify the effects of soil-structure interaction on the structural response considering both aleatory and epistemic uncertainties. The goal is achieved by examining the response of established rheological single-degree-of-freedom systems located on shallow-foundation and excited by ground motions with different spectral characteristics. In this regard, four main phases are followed. First, the effects of seismic soil-structure interaction on the response of structures with linear behaviour are investigated using a robust stochastic approach. Herein, the soil-foundation interface is modelled by an equivalent linear cone model. This phase is mainly considered to examine the influence of soil-structure interaction on the approach that has been adopted in the building codes for developing design spectrum and defining the seismic forces acting on the structure. Second, the effects of structural nonlinearity on the role of soil-structure interaction in modifying seismic structural response are studied. The same stochastic approach as phase 1 is followed, while three different types of structural force-deflection behaviour are examined. Third, a systematic fashion is carried out to look for any possible correlation between soil, structural, and system parameters and the degree of soil-structure interaction effects on the structural response. An attempt is made to identify the key parameters whose variation significantly affects the structural response. In addition, it is tried to define the critical range of variation of parameters of consequent. Finally, the impact of soil-foundation interface nonlinearity on the soil-structure interaction analysis is examined. In this regard, a newly developed macro-element covering both material and geometrical soil-foundation interface nonlinearity is implemented in a finite-element program Raumoko 3D. This model is then used in an extensive probabilistic simulation to compare the effects of linear and nonlinear soil-structure interaction on the structural response. This research is concluded by reviewing the current design guidelines incorporating soil-structure interaction effects in their design procedures. A discussion is then followed on the inadequacies of current procedures based on the outcomes of this study.
This paper discusses the seismic performance of the standard RC office building in Christchurch that is given as a structural design example in NZS3101, the concrete structures seismic standard in New Zealand. Firstly the push-over analysis was carried out to evaluate the lateral load carrying capacity of the RC building and then to compare that carrying capacity with the Japanese standard law. The estimated figures showed that the carrying capacity of the New Zealand standard RC office building of NZS3101:2006 was about one third of Japanese demanded carrying capacity. Secondly, time history analysis of the multi-mass system was performed to estimate the maximum response story drift angle using recorded ground motions. Finally, a three-dimensional analysis was carried out to estimate the response of the building to the 22nd February, 2011 Canterbury earthquake. The following outcomes were obtained. 1) The fundamental period of the example RC building is more than twice that of Japanese simplified calculation, 2) The example building’s maximum storey drift angle reached 2.5% under the recorded ground motions. The main purpose of this work is to provide background information of seismic design practice for the reconstruction of Christchurch.
The seismic response of unreinforced masonry (URM) buildings, in both their as-built or retrofitted configuration, is strongly dependent on the characteristics of wooden floors and, in particular, on their in-plane stiffness and on the quality of wall-to-floor connections. As part of the development of alternative performance-based retrofit strategies for URM buildings, experimental research has been carried out by the authors at the University of Canterbury, in order to distinguish the different elements contributing to the whole diaphragm's stiffness. The results have been compared to the ones predicted through the use of international guidelines in order to highlight shortcomings and qualities and to propose a simplified formulation for the evaluation of the stiffness properties.
The paper discusses modelling of cyclic stress-strain behaviour of soil, in particular a simple model that can produce a desired stiffness and hysteretic damping for a given strain level as observed in laboratory testing is formulated. The unloading-reloading relationship is developed for total stress seismic site response analysis with appropriate damping at large strain. The constitutive model employs a hyperbolic equation as the backbone curve, and uses a modification of the extended Masing unloading-reloading relationship leading to correct measured modulus reduction and damping curves simultaneously. A quasi-static cyclic loading of increasing amplitude is used to demonstrate the model’s performance and its capability to allow improved modelling of the magnitude of energy dissipation based on an experimental program on native sandy soils from Christchurch, New Zealand.
Impact between structures of bridge sections can play a major, unexpected role in seismic structural damage. Linear and non-linear models are developed to analyze structural impact and response of two single-degree-of-freedom structures, representing adjacent buildings or bridge sections. The analyses presented assess probability of impact, displacement change due to impact, and the probability of increased displacement due to impact. These are assessed over a matrix of structural periods for each degree-of-freedom, different impact coefficients of restitution, and a probabilistically scaled suite of earthquake events. Linear versus non-linear effects are assessed using a Ramberg-Osgood non-linear model for column inelasticity. The normalized distance, or gap-ratio (GR), defined as a percentage of the summed spectral displacements, is used to create probabilistic design requirements. Increasing GR and structural periods that are similar (T2/T1~0.8-1.25) significantly decrease the likelihood of impact, and vice-versa. Including column inelasticity and decreasing coefficient of restitution decrease displacement increases due to impact and thus reduce potential damage. A minimum GR~0.5-0.9 ensures that any displacement increases will be less than 10% for 90% of ground motions over all structural period combinations (0.2-5.0sec). These results enable probabilistic design guidelines to manage undesirable effects of impact– an important factor during the recent Canterbury, New Zealand Earthquakes.
In 2010 and 2011, Aotearoa New Zealand was hit by a number of major disasters involving loss of human life and severe disruption to social, ecological and economic wellbeing. The Pike River mine explosions were closely followed by a sequence of major earthquakes in Christchurch, seismic events that have permanently altered the lives of thousands of people in our third largest city, the closure of the central business district and the effective abandonment of whole residential areas. In early October 2011, the ship, Rena, grounded on a reef off the port of Tauranga and threatened a major oil spill throughout the Bay of Plenty, where local communities with spiritual and cultural connections to the land depend on sea food as well as thrive on tourism. The Council for Social Work Education Aotearoa New Zealand (CSWEANZ), representing all the Schools of Social Work in New Zealand, held a ‘Disaster Curriculum’ day in November 2011, at which social workers and Civil Defence leaders involved in the Christchurch earthquakes, the Rena Disaster, Fiji floods and the Boxing Day tsunami presented their narrative experience of disaster response and recovery. Workshops discussed and identified core elements that participants considered vital to a social work curriculum that would enable social work graduates in a range of community and cultural settings to respond in safe, creative and informed ways. We present our core ideas for a social work disaster curriculum and consider a wide range of educational content based on existing knowledge bases and new content within a disaster framework. http://www.swsd-stockholm-2012.org/
PAUL GOLDSMITH to the Minister of Finance: What steps is the Government taking to support new jobs and build a productive and competitive economy?
Rt Hon WINSTON PETERS to the Minister responsible for the GCSB: Specifically, have there been staff issues associated with the Government Communications Security Bureau and Dotcom affair brought to his attention by the Government Communications Security Bureau or members of the New Zealand Police, in which such staff members no longer work in their previous capacity for the Government Communications Security Bureau or any government agency; if so, what were the circumstances?
DAVID SHEARER to the Prime Minister: Further to his answers to the first supplementary question to Oral Question No 1 on 26 September and the first supplementary question to Oral Question No 1 yesterday, does he now know on what date the Government Communications Security Bureau was first told that its surveillance of Kim Dotcom was illegal?
ALFRED NGARO to the Minister for Social Development: What recent announcements has she made regarding providing extra financial assistance to grandparents raising grandchildren and other kin-carers?
Hon DAVID PARKER to the Minister of Finance: When he said yesterday that with a "relatively high" exchange rate, our exporters "have been sufficiently resilient to be able to grow export volumes and value" did he mean that all export sectors have been growing, and according to Statistics New Zealand, in 2008 dollars what is the percentage change in exports of simply and elaborately transformed manufactured goods from the 2008 to 2012 financial years?
METIRIA TUREI to the Prime Minister: Does he stand by his statement, in response to a question about whether he will support my Income Tax (Universalisation of In-work Tax Credit) Amendment Bill that "she wants to give the same millionaires yet more money to raise their kids"?
SHANE ARDERN to the Minister for Primary Industries: What progress can he report on the Primary Growth Partnership Initiative?
JACINDA ARDERN to the Minister for Social Development: What vulnerabilities were identified in the report prepared by Dimension Data on the security of the Work and Income kiosks?
Dr JACKIE BLUE to the Minister of Health: What reports has he received on improving the quality and efficiency of health services?
TE URUROA FLAVELL to the Minister of Broadcasting: How does he ensure that the legislative requirement for TVNZ to provide high-quality content that reflects Māori perspectives is reflected in the programming strategy for TV1 and TV2?
CHRIS HIPKINS to the Minister of Education: Is she confident that the information she relied upon in deciding on proposals for school closures and mergers in Christchurch was robust and reliable; if so, why?
CHRIS AUCHINVOLE to the Minister for Canterbury Earthquake Recovery: What reports has he received on the availability of insurance cover to support the rebuilding of Canterbury following the seismic events?
