Search

found 20 results

Images for scale; more images...

Research papers, University of Canterbury Library

Research Report No.2010-03Ground motion prediction equations (GMPEs) for geometric-mean pseudo-spectral acceleration amplitudes from New Zealand (NZ) earthquakes are developed. A database of 2437 three-component ground motion records is developed by applying stringent quality criteria to the historically recorded events in NZ. Despite the large number of records, the database is deficient in empirical records from large magnitude events recorded at close distances to the fault rupture plane. As a result, the basis for the NZ-specific GMPE development is to examine the applicability of foreign GMPEs for similar tectonic regions and then modify the most applicable GMPEs based on both theoretical and statistically significant empirically-driven arguments. For active shallow crustal events, five different GMPEs are considered. It was found that the McVerry et al. (2006) model, which is the current model upon which seismic design guidelines and site-specific seismic hazard analyses in NZ are based, provided the worst fit to the NZ database, and that the Chiou et al. (2010) (C10) modification of the Chiou and Youngs (2008) model was the most applicable. Discrepancies between the C10 model and the NZ database that were empirically identified and theoretically justified were used to modify the C10 model for: (i) small magnitude scaling; (ii) scaling of short period ground motion from normal faulting events in volcanic crust; (iii) scaling of ground motions on very hard rock sites; (iv) anelastic attenuation in the NZ crust; and (v) consideration of the increased anelastic attenuation in the Taupo Volcanic Zone (TVZ). For subduction slab events, initially three models were considered. It was found that all of the models had some significant biases with respect to applicability for NZ. The Zhao et al. (2006) (Z06) model was selected because of the rigorous database upon which it was developed and modified by: (i) NZ-specific scaling at small magnitudes; (ii) path scaling at large distances; (iii) consideration of the increased TVZ attenuation; and (iv) revision of the standard deviation model. Based on these modifications the developed model showed no bias of the inter- and intra-event residuals as a function of various predictor variables. The standard deviation of the residuals using the revised standard deviation model also indicated that the model has an adequate precision. Three GMPEs were considered for subduction interface events. The Zhao et al. (2006) (Z06) model was the best performing model with only bias exhibited in the site response model, and possible over-prediction of large magnitude events. The Z06 interface model was modified to account for site response and magnitude scaling using the same functional forms as those of the developed active shallow crustal and subduction slab models. The developed model showed no bias of the inter- and intra-event residuals as a function of various predictor variables. The developed GMPEs include specific features as evident in the NZ database; consistent scaling for parameters not well constrained by the NZ database; and pseudo-spectral amplitudes for vibration periods from 0.01 to 10 seconds. Hence, these models represent a significant advance in the state-of-the art for empirical ground motion prediction in NZ.

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. Wayne Alexander has now lived through 3 earthquakes with a richter scale of 7 plus. 1968 Inangahua, 1989 San Francisco and 2010 Christchurch. His father also lived through three of the same magnitude. They live in one of the old Deans family residences which sustained chimney damage in Saturday's earthquake".

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. Wayne Alexander has now lived through 3 earthquakes with a richter scale of 7 plus. 1968 Inangahua, 1989 San Francisco and 2010 Christchurch. His father also lived through three of the same magnitude. Wayne and his son Lochlan Alexander (2 yr). They live in one of the old Deans family residences, which sustained chimney damage in Saturday's earthquake".

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. Wayne Alexander has now lived through 3 earthquakes with a richter scale of 7 plus. 1968 Inangahua, 1989 San Francisco and 2010 Christchurch. His father also lived through three of the same magnitude. (L-R) Lochlan Alexander (2 yr), Wayne Alexander and Annemarie Winstone (mother of Lochlan). They live in one of the old Dean's family residences which sustained chimney damage in Saturday's earthquake".

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. Wayne Alexander has now lived through 3 earthquakes with a richter scale of 7 plus. 1968 Inangahua, 1989 San Francisco and 2010 Christchurch. His father also lived through three of the same magnitude. (L-R) Lochlan Alexander (2 yr), Wayne Alexander and Annemarie Winstone (mother of Lochlan). They live in one of the old Deans family residences which sustained chimney damage in Saturday's earthquake".

Images, eqnz.chch.2010

Rolleston/Burnham, South Island, NZ It's been a busy few weeks! Was away on geology fieldtrips all the previous two weeks, then on Saturday morning 4th September 2010 at 4.35 am we got woken in Westport to a reasonable but very long earthquake. My husband was back in Christchurch at the time and texted me saying "are you ok?". I replied, "yes!"...

Articles, UC QuakeStudies

This report provides information on the locations and character of active geological faults and folds in Mackenzie District. The faults are mapped at a district scale and the information is intended to highlight areas where there is a risk of fault movement, and where more detailed investigations should be done if development is proposed in that area(depending on the potential activity of the fault and the type of development proposed). Most of the faults and folds identified at the ground surface in Mackenzie District are in rural or very sparsely populated areas. In addition, most of the faults have relatively long recurrence intervals (long-term average time between fault movements) in the order of several thousand years. Following the Ministry for the Environment Active Fault Guidelines, normal residential development would be allowed on or near faults with recurrence intervals this long. There are no recommendations associated with this report. The information in the report will be reviewed as required, after the remaining district reports are completed in the region. See Object Overview for background and usage information.

Research papers, University of Canterbury Library

A team of earthquake geologists, seismologists and engineering seismologists from GNS Science, NIWA, University of Canterbury, and Victoria University of Wellington have collectively produced an update of the 2002 national probabilistic seismic hazard (PSH) model for New Zealand. The new model incorporates over 200 new onshore and offshore fault sources, and utilises newly developed New Zealand-based scaling relationships and methods for the parameterisation of the fault and subduction interface sources. The background seismicity model has also been updated to include new seismicity data, a new seismicity regionalisation, and improved methodology for calculation of the seismicity parameters. Background seismicity models allow for the occurrence of earthquakes away from the known fault sources, and are typically modelled as a grid of earthquake sources with rate parameters assigned from the historical seismicity catalogue. The Greendale Fault, which ruptured during the M7.1, 4 September 2010 Darfield earthquake, was unknown prior to the earthquake. However, the earthquake was to some extent accounted for in the PSH model. The maximum magnitude assumed in the background seismicity model for the area of the earthquake is 7.2 (larger than the Darfield event), but the location and geometry of the fault are not represented. Deaggregations of the PSH model for Christchurch at return periods of 500 years and above show that M7-7.5 fault and background source-derived earthquakes at distances less than 40 km are important contributors to the hazard. Therefore, earthquakes similar to the Darfield event feature prominently in the PSH model, even though the Greendale Fault was not an explicit model input.

Audio, Radio New Zealand

Questions to Ministers 1. Dr RUSSEL NORMAN to the Minister of Justice: Is it his view that the justice system should provide rehabilitation and give people the chance to change? 2. Hon ANNETTE KING to the Minister for Canterbury Earthquake Recovery: Is he satisfied with progress on the recovery from the Canterbury earthquake so far? 3. DAVID BENNETT to the Minister of Broadcasting: What recent announcements have been made regarding digital switchover? 4. SUE MORONEY to the Minister of Education: What policy initiatives has she developed for early childhood education? 5. AARON GILMORE to the Minister of Civil Defence: What is the update on the Canterbury Civil Defence states of emergency? 6. Hon DAVID CUNLIFFE to the Minister of Finance: Did the Treasury evaluate the net effect on South Canterbury Finance's position of the February 2010 acquisition of Helicopters (NZ) Ltd and Scales Corporation shares, including the effect of the transaction on the recoverability or impairment of South Canterbury Finance's $75 million loan to its parent company, Southbury Group Ltd? 7. LOUISE UPSTON to the Minister of Energy and Resources: Will Cantabrians whose chimneys have been significantly damaged by the recent earthquake be covered by the Earthquake Commission to replace their old log burners or open fires with new efficient heaters? 8. Hon TREVOR MALLARD to the Minister of Education: What support will be available in 2011 to schools that have very poor numeracy national standards results in 2010? 9. SANDRA GOUDIE to the Minister of Corrections: What support is the Corrections Department offering to Canterbury community groups and individuals to help with earthquake recovery? 10. DARIEN FENTON to the Minister of Labour: Does she stand by her statement to the House on 14 September 2010 that the 90-day trial provisions "do not take away rights"? 11. CHESTER BORROWS to the Minister of Housing: What is the Government doing to assist people whose homes are not habitable following the Canterbury earthquake? 12. PHIL TWYFORD to the Minister of Local Government: When he said in the House yesterday that the Auckland Transition Agency "ran a tender to deliver an enterprise resource planning system" was he referring to merely the $14.3 million contract for the implementation of the Enterprise Resource Planning system or was he referring to the full contract of $53.8 million to deliver the Enterprise Resource Planning system? Questions to Members 1. DARIEN FENTON to the Chairperson of the Transport and Industrial Relations Committee: How many submissions have been received on the Employment Relations Amendment Bill (No 2)?

Research papers, University of Canterbury Library

This report describes in-plane experimental testing and numerical modelling of timberconcrete floor diaphragms. The experimental tests investigated the in-plane stiffness of the diaphragm and the stiffness and strength of different connections between the diaphragm and the lateral load resisting system. The test model was 1/3 scale and three meters square in plan. Seven tests with a different kind of connection between the floor and the rigid lateral supports (which simulated a timber lateral load resisting system) have been performed. The results of the experimental testing are used to calibrate numerical models which are used to investigate the effects of the floor flexibility on the seismic behaviour of post-tensioned timber buildings. For the experimental tests, screw and nail fasteners were used to connected to floor unit to the lateral supports. These fasteners were embedded into the concrete slab or timber edge joints at different orientations. The stiffness of the diaphragm connections was vastly different for each detail. Screws installed at a 45? angle (inclined) to the lateral supports were four times stiffer than the screws installed orthogonal to the lateral supports. The initial stiffness of the inclined fasteners was similar for timber-to-timber and concrete-to-timber connections. For the timberto- timber connections the orientation did not seem to influence the strength of the connection. The tested diaphragm had an uncracked stiffness of 4000 kN/mm and a cracked stiffness of 300 kN/mm. For the tested floor unit it was concluded that the influence of the diaphragm flexibility was negligible compared to the connector flexibility. The floor flexibility can be idealized as three different parts, the deformation of the connectors, the shear deformation of the diaphragm and the flexural deformation of the diaphragm. The numerical analyses showed that in most perceivable situations the connection deformation will govern the in-plane seismic response of the floor. Hence, it is justified to model it as a single-degree-of-freedom (SDOF) element. The influence of the floor flexibility on the seismic response of post-tensioned timber buildings is small. In most cases neglecting the floor flexibility is a conservative approach for the structural design of the building. However, structures with stiff walls and long floor spans there can be a significant amplification of the seismic response. For that case, a simple SDOF representation is proposed. Code-based recommendations for predicting the peak floor accelerations are found to be inadequate. A methodology is proposed to more accurately predict the expected peak floor accelerations for design

Research papers, University of Canterbury Library

Research Report: 2010-02The objective in writing this report is to provide a guide to structural engineers on how to assess the potential seismic performance of existing hollow-core floors in buildings and the steps involved in the design of new floors. Hollow-core units in New Zealand do not contain stirrups within the precast concrete section. This is due to the way that they are manufactured. The only reinforcement in the great majority of hollow-core units consists of pretensioned strands that are located close to the soffit. A consequence of this is that hollow-core units have a number of potential brittle failure modes that can occur when adverse structural actions are induced in the units. These adverse actions can be induced in a major earthquake due to the relative vertical, horizontal and rotational displacements that occur between hollow-core units and adjacent structural elements, such as beams or structural walls. A number of large scale structural tests backed up by analytical research has shown that extensive interaction occurs between floors containing prestressed precast units and other structural elements, such as walls and beams. The constraint that prestressed units in a floor can apply to adjacent beams can result in an increase in strength of the beams to a considerably greater strength than that indicated in editions of the New Zealand Structural Concrete Standard published prior to 2006. The extent of this increase is such that it could in some cases result in the development of a non-ductile failure mechanism instead of the ductile failure mechanism assumed in the design. Prestressed floor units tie the floor bays together leaving a weak section where the floor joins to supporting structural elements. The restraint provided by the prestress restricts the opening of cracks within the bay. In the event of an earthquake this restraint can result in wide cracks developing at some of the boundaries to floor bays. These cracks may have a significant influence on the performance of the floor when it acts as a diaphragm to transfer seismic forces to the lateral force resisting structural elements in the building. The report contains details of; 1. The different failure modes, which may be induced in hollow-core floors, and the failure modes that may develop in a buildings due to the presence of hollow-core units in the floors; 2. Criteria that may be used to assess the magnitude of the design earthquake which may be safely resisted by a hollow-core floor in a building; 3. Details of how construction practice related to the use of hollow-core floors in New Zealand has changed over the last five decades. This highlights particular aspects that need to be considered in carrying out an assessment of existing hollow-core floors; 4. Information on how a new hollow-core floor may be designed to be consistent with the Earthquake Actions Standard, NZS1170.5: 2004 and the Structural Concrete Standard, NZS3101: 2006 (plus Amendment 2); 5. A review of the research findings relevant to the behaviour of New Zealand hollow-core floors under earthquake conditions. Research that was used to develop the assessment and design criteria is described together with details of how the different criteria were developed from this work.