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Research papers, Lincoln University

The housing and mortgage market in Christchurch experienced significant changes since the 2011 earthquake, especially after the reconstruction of the city. The increasing speed of Christchurch average house price exceed the average house price of the whole country, as well as the number of new dwellings. By this regard, this study surveyed the households in Christchurch to analyze the effect of the earthquake on housing and mortgage market. This includes factors such as housing price, interest rate, government policy and socioeconomic factors in terms of age, gender, educational attainment, income, marital status and family life cycle. Logistic regression model is used to analyze the data. The study provides an overview of the housing market and mortgage market in Christchurch. The logistic regression, results show changes on sensitivity between the socio-economic factors and house purchase, as well as mortgage borrowing pre- and post-earthquake. The result indicates that the earthquake in Christchurch has affected households’ decision on house purchase and mortgage borrowing.

Research papers, University of Canterbury Library

Capacity design and hierarchy of strength philosophies at the base of modern seismic codes allow inelastic response in case of severe earthquakes and thus, in most traditional systems, damage develops at well-defined locations of reinforced concrete (RC) structures, known as plastic hinges. The 2010 and 2011 Christchurch earthquakes have demonstrated that this philosophy worked as expected. Plastic hinges formed in beams, in coupling beams and at the base of columns and walls. Structures were damaged permanently, but did not collapse. The 2010 and 2011 Christchurch earthquakes also highlighted a critical issue: the reparability of damaged buildings. No methodologies or techniques were available to estimate the level of subsequent earthquakes that RC buildings could still sustain before collapse. No repair techniques capable of restoring the initial condition of buildings were known. Finally, the cost-effectiveness of an eventual repair intervention, when compared with a new building, was unknown. These aspects, added to nuances of New Zealand building owners’ insurance coverage, encouraged the demolition of many buildings. Moreover, there was a perceived strong demand from government and industry to develop techniques for assessing damage to steel reinforcement bars embedded in cracked structural concrete elements. The most common questions were: “Have the steel bars been damaged in correspondence to the concrete cracks?”, “How much plastic deformation have the steel bars undergone?”, and “What is the residual strain capacity of the damaged bars?” Minimally invasive techniques capable of quantifying the level and extent of plastic deformation and residual strain capacity are not yet available. Although some studies had been recently conducted, a validated method is yet to be widely accepted. In this thesis, a least-invasive method for the damage-assessment of steel reinforcement is developed. Based on the information obtained from hardness testing and a single tensile test, it is possible to estimate the mechanical properties of earthquake-damaged rebars. The reduction in the low-cycle fatigue life due to strain ageing is also quantified. The proposed damage assessment methodology is based on empirical relationships between hardness and strain and residual strain capacity. If damage is suspected from in situ measurements, visual inspection or computer analysis, a bar may be removed and more accurate hardness measurements can be obtained using the lab-based Vickers hardness methodology. The Vickers hardness profile of damaged bars is then compared with calibration curves (Vickers hardness versus strain and residual strain capacity) previously developed for similar steel reinforcement bars extracted from undamaged locations. Experimental tests demonstrated that the time- and temperature-dependent strain-ageing phenomenon causes changes in the mechanical properties of plastically deformed steels. In particular, yield strength and hardness increases, whereas ductility decreases. The changes in mechanical properties are quantified and their implications on the hardness method are highlighted. Low-cycle fatigue (LCF) failures of steel reinforcing bars have been observed in laboratory testing and post-earthquake damage inspections. Often, failure might not occur during a first seismic event. However, damage is accumulated and the remaining fatigue life is reduced. Failure might therefore occur in a subsequent seismic event. Although numerous studies exist on the LCF behaviour of steel rebars, no studies had been conducted on the strain-ageing effects on the remaining fatigue life. In this thesis, the reduction in fatigue life due to this phenomenon is determined through a number of experimental tests.

Audio, Radio New Zealand

There have been dramatic scenes at the America's cup in Bermuda with Team New Zealand capsizing at the start of its second race of the day against the Bristish team Ben Ainslie Racing. Our America's Cup correspondent Todd Niall was at the Team New Zealand base. Transport Minister Simon Bridges has been caught trying to block an Official Information request for details about a proposed new 50 million dollar Auckland railway line. Kiwirail argued it was legally required to release the information, but the idea of releasing that information was making Mr Bridges 'extremely uncomfortable.' A man believed to be an Algerian student has attacked a police officer with a hammer outside Notre-Dame Cathedral in Paris. Our correspondent Peter Allen says there is still a heavy police presence. The Labour Party says the government is short changing the health sector to the tune of $2.3 billion. The party's leader Andrew Little says funding hasn't kept up with the growing population and changing demographic. The United States secretary of state Rex Tillerson used a fleeting visit to Wellington yesterday to emphasise the importance of the Asia Pacific region and denying the US is stepping back from involvement here. Foreign affairs minister Gerry Brownlee says the US pulling out of the TPP doesn't prove anything. The immediate aftermath of the devastating 2011 Christchurch earthquake and its ongoing impact on residents' mental health is being described as a recovery of two halves. The latest wellbeing survey from the Canterbury District Health Board shows that one in five people, predominantly those living in the eastern suburbs, say they experience stress most or all of the time. Nicky Wagner, the Minister supporting Greater Christchurch Regeneration, says the city has a good quality of life when compared to the rest of the country, despite a new survey showing one in five people say they experience stress most or all of the time. Ms Wagner, says 82 per cent have a good or very good quality of life in Christchurch, which compares with 81 percent nationwide. She says the east side of the city is very low lying and suffered the most damage and work is still being down in that area.