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.
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 magnitude Mw 6.2 earthquake of February 22nd 2011 that struck beneath the city of Christchurch, New Zealand, caused widespread damage and was particularly destructive to the Central Business District (CBD). The shaking caused major damage, including collapses of structures, and initiated ground failure in the form of soil liquefaction and consequent effects such as sand boils, surface flooding, large differential settlements of buildings and lateral spreading of ground towards rivers were observed. A research project underway at the University of Canterbury to characterise the engineering behaviour of the soils in the region was influenced by this event to focus on the performance of the highly variable ground conditions in the CBD. This paper outlines the methodology of this research to characterise the key soil horizons that underlie the CBD that influenced the performance of important structures during the recent earthquakes, and will influence the performance of the rebuilt city centre under future events. The methodology follows post-earthquake reconnaissance in the central city, a desk study on ground conditions, site selection, mobilisation of a post-earthquake ground investigation incorporating the cone penetration test (CPT), borehole drilling, shear wave velocity profiling and Gel-push sampling followed by a programme of laboratory testing including monotonic and cyclic testing of the soils obtained in the investigation. The research is timely and aims to inform the impending rebuild, with appropriate information on the soils response to dynamic loading, and the influence this has on the performance of structures with various foundation forms.
Despite over a century of study, the relationship between lunar cycles and earthquakes remains controversial and difficult to quantitatively investigate. Perhaps as a consequence, major earthquakes around the globe are frequently followed by 'prediction' claims, using lunar cycles, that generate media furore and pressure scientists to provide resolute answers. The 2010-2011 Canterbury earthquakes in New Zealand were no exception; significant media attention was given to lunarderived earthquake predictions by non-scientists, even though the predictions were merely 'opinions' and were not based on any statistically robust temporal or causal relationships. This thesis provides a framework for studying lunisolar earthquake temporal relationships by developing replicable statistical methodology based on peer reviewed literature. Notable in the methodology is a high accuracy ephemeris, called ECLPSE, designed specifically by the author for use on earthquake catalogs, and a model for performing phase angle analysis. The statistical tests were carried out on two 'declustered' seismic catalogs, one containing the aftershocks from the Mw7.1 earthquake in Canterbury, and the other containing Australian seismicity from the past two decades. Australia is an intraplate setting far removed from active plate boundaries and Canterbury is proximal to a plate boundary, thus allowing for comparison based on tectonic regime and corresponding tectonic loading rate. No strong, conclusive, statistical correlations were found at any level of the earthquake catalogs, looking at large events, onshore events, offshore events, and the fault type of some events. This was concluded using Schuster's test of significance with α=5% and analysis of standard deviations. A few weak correlations, with p-5-10% of rejecting the null hypothesis, and anomalous standard deviations were found, but these are difficult to interpret. The results invalidate the statistical robustness of 'earthquake predictions' using lunisolar parameters in this instance. An ambitious researcher could improve on the quality of the results and on the range of parameters analyzed. The conclusions of the thesis raise more questions than answers, but the thesis provides an adaptable methodology that can be used to further investigation the problem.
Questions to Ministers
1. DAVID SHEARER to the Prime Minister: Does he stand by his statement in the House yesterday, in answer to Oral Question No 2, that his Government is selling assets because "New Zealanders want less debt, more productive assets, and an economy that is going to function, not a load more debt"?
2. PAUL GOLDSMITH to the Minister for Economic Development: What progress is the Government making in implementing its economic growth agenda?
3. PHIL TWYFORD to the Minister of Transport: Does the Government consider it important for its transport spending to be cost-effective and provide a good return on investment?
4. Dr RUSSEL NORMAN to the Minister for State Owned Enterprises: What, according to the Crown Ownership Monitoring Unit, was the average total shareholder return of Genesis, Meridian, Mighty River Power and Solid Energy over the last five years and how does that compare to the average cost of borrowing to the Government right now?
5. NICKY WAGNER to the Minister of Local Government: What reports has he received on how much rates increased nationally in the decade since the Local Government Act 2002 and how does this compare to the previous decade?
6. GRANT ROBERTSON to the Minister for the Environment: Does he stand by his statement made in the House yesterday in relation to the grounding of the Rena that "the statute sets down very clearly that I as Minister for the Environment should not be encouraging or discouraging a proper, independent decision by Environment Bay of Plenty as to whether they should or should not take a prosecution"?
7. KANWALJIT SINGH BAKSHI to the Minister of Broadcasting: What recent announcements has the Government made on progress towards digital switchover?
8. Rt Hon WINSTON PETERS to the Prime Minister: Does he still have confidence in all his Ministers?
9. Hon LIANNE DALZIEL to the Minister for Canterbury Earthquake Recovery: How many written comments were received on the draft Recovery Plan for the Christchurch CBD and is it his intention to consider them all before making a decision on the draft Recovery Plan for the CBD, in accordance with the process set out on the Canterbury Earthquake Recovery Authority's website?
10. MELISSA LEE to the Minister of Internal Affairs: What recent steps have there been to promote New Zealand citizenship as a successful settlement pathway for migrants?
11. CLARE CURRAN to the Minister of Broadcasting: Does he stand by the Prime Minister's statement in relation to the appointment of the Prime Minister's electorate chairman Stephen McElrea to the NZ On Air board that "if you look at the vast array of appointments we make, I think the balance is about right"?
12. CATHERINE DELAHUNTY to the Minister of Education: Will she rule out implementing Treasury's advice to increase class sizes in schools?
