Digitally manipulated image of the damaged Cathedral of the Blessed Sacrament, superimposed with a seismograph trace. The photographer comments, "What we want to forget, but must remember".
A year after the first earthquake on 4 September 2010, aftershocks continue to be felt in Canterbury, and they're not always seismic ones. When buildings collapse or are cordoned off, or even just closed for repairs - what happens to the lives and livelihoods of those who used to fill them with noise and energy? Kris Vavasour returns to Lyttelton to catch up with performers and friends, to hear about life in an altered landscape.
Unreinforced masonry (URM) buildings have repeatedly been shown to perform poorly in large magnitude earthquakes, with both New Zealand and Australia having a history of past earthquakes that have resulted in fatalities due to collapsed URM buildings. A comparison is presented here of the URM building stock and the seismic vulnerability of Christchurch and Adelaide in order to demonstrate the relevance to Australian cities of observations in Christchurch resulting from the 2010/2011 Canterbury earthquake swarm. It is shown that the materials, architecture and hence earthquake strength of URM buildings in both countries is comparable and that Adelaide and other cities of Australia have seismic vulnerability sufficient to cause major damage to their URM buildings should a design level earthquake occur. Such an earthquake is expected to cause major building damage, and fatalities should be expected.
There is a critical strand of literature suggesting that there are no ‘natural’ disasters (Abramovitz, 2001; Anderson and Woodrow, 1998; Clarke, 2008; Hinchliffe, 2004). There are only those that leave us – the people - more or less shaken and disturbed. There may be some substance to this; for example, how many readers recall the 7.8 magnitude earthquake centred in Fiordland in July 2009? Because it was so far away from a major centre and very few people suffered any consequences, the number is likely to be far fewer than those who remember (all too vividly) the relatively smaller 7.1 magnitude Canterbury quake of September 4th 2010 and the more recent 6.3 magnitude February 22nd 2011 event. One implication of this construction of disasters is that seismic events, like those in Canterbury, are as much socio-political as they are geological. Yet, as this paper shows, the temptation in recovery is to tick boxes and rebuild rather than recover, and to focus on hard infrastructure rather than civic expertise and community involvement. In this paper I draw upon different models of community engagement and use Putnam’s (1995) notion of ‘social capital’ to frame the argument that ‘building bridges’ after a disaster is a complex blend of engineering, communication and collaboration. I then present the results of a qualitative research project undertaken after the September 4th earthquake. This research helps to illustrate the important connections between technical rebuilding, social capital, recovery processes and overall urban resilience.
Text reads 'One of the many faces of Mother Nature' and the cartoon shows a moon with a seismic graph across it that has taken on the shape of a face. A second version does not have the moon and a third version has the face say 'I have a few faults'. Context - The Christchurch earthquakes. Three versions of this cartoon are available Quantity: 3 digital cartoon(s).
In order to provide information related to seismic vulnerability of non-ductile reinforced concrete (RC) frame buildings, and as a complementary investigation on innovative feasible retrofit solutions developed in the past six years at the University of Canterbury on pre-19170 reinforced concrete buildings, a frame building representative of older construction practice was tested on the shake table. The specimen, 1/2.5 scale, consists of two 3-storey 2-bay asymmetric frames in parallel, one interior and one exterior, jointed together by transverse beams and floor slabs. The as-built (benchmark) specimen was first tested under increasing ground motion amplitudes using records from Loma Prieta Earthquake (California, 1989) and suffered significant damage at the upper floor, most of it due to lap splices failure. As a consequence, in a second stage, the specimen was repaired and modified by removing the concrete in the lap splice region, welding the column longitudinal bars, replacing the removed concrete with structural mortar, and injecting cracks with epoxy resin. The modified as-built specimen was then tested using data recorded during Darfield (New Zealand, 2010) and Maule (Chile, 2010) Earthquakes, with whom the specimen showed remarkably different responses attributed to the main variation in frequency content and duration. In this contribution, the seismic performance of the three series of experiments are presented and compared.
The cartoon shows a house for sale in Christchurch after the earthquakes; there is a jagged rip through the house and the road outside that looks like a seismic graph after a lot of activity. The 'For Sale' sign says 'Open Plan living, open home, Seismologist's dream!'. Context - A house wrecked by the Christchurch earthquakes of September 4th 2010, February 22 2011 and June 13 2011. Quantity: 1 digital cartoon(s).
In the top frames two children shout 'four point one', 'three point six', and 'five point two' and in the frame below it is seen that they are responding to bumps in the road as their mother drives through Christchurch streets. Context - The children have become expert at guessing the seismic intensity of earthquakes in Christchurch and are now applying them to bumps in the road. Colour and black and white versions available Quantity: 2 digital cartoon(s).
A Christchurch seismic monitor churns out reams of paper with wild fluctuations showing earthquakes and aftershocks. Nearby two men examine a second monitor and one of them says 'This one's connected to Gerry Brownlee!' The reams of paper show a perfectly straight line - it appears that nothing is going on in Gerry Brownlee's head. Context - A sense that the Minister for Earthquake Recovery is being less than effective. Colour and black and white versions available Quantity: 2 digital cartoon(s).
An overview of the 22 February 2011 Christchurch earthquake is presented in the context of characterization of extreme/rare events. Focus is given to the earthquake source, observed near-source strong ground motions, and effects of site response, while structural response and consequences are mentioned for completeness. For each of the above topics comparisons and discussions are made with predictive models for each of phenomena considered. In light of the observations and predictive model comparisons, the author’s opinion on improving the characterization of such extreme/rare events, and their appropriate consideration in seismic design is presented
In the aftermath of the 22 February 2011 earthquake, the Natural Hazards Research Platform (NHRP) initiated a series of Short Term Recovery Projects (STRP) aimed at facilitating and supporting the recovery of Christchurch from the earthquake impacts. This report presents the outcomes of STRP 6: Impacts of Liquefaction on Pipe Networks, which focused on the impacts of liquefaction on the potable water and wastewater systems of Christchurch. The project was a collaborative effort of NHRP researchers with expertise in liquefaction, CCC personnel managing and designing the systems and a geotechnical practitioner with experience/expertise in Christchurch soils and seismic geotechnics.
A photograph of a sign taped to a window. The sign includes a bullet pointed list of humorous observations about Christchurch following the February 2011 earthquake. The sign reads, "You know you're from Christchurch when: you use the term 'liquefaction' and 'seismic design' in casual conversation; digging a hole and shitting in your garden is no longer weird; your mayor describes the city as munted. If he means FUBARed, you agree; weaving through car size potholes on the street is no longer weird; a shower is heaven; you have a preference of which kind of silt you'd rather shovel, dry or wet; you see tanks...driving around town; you are always noting what you are under; due to frequent aftershocks during the night, you sleep like a baby - every 10 minutes you wake up and shit yourself".
The cartoon shows members of the 'Japan Seismic Institute studying an earthquake graph; one of them says 'Where was that Kiwi moonman when we wanted him?' Depicted also is thew 'moonman' Ken Ring as a wizard studying an astrological chart. Behind them all Japan is depicted as a devastated wasteland. Context - the Japanese earthquake and tsunami of 4th March 2011 and the present threat of a nuclear catastrophe. Also the so-called Moon Man, astrologer Ken Ring, who predicted that Christchurch would be hit by a huge earthquake today (20 March 2011). His claims have terrified Cantabrians and led to people fleeing Christchurch. Quantity: 1 digital cartoon(s).
Text reads 'The earth moved...... and so did the government's infrastructure spending estimate'. Centre cartoon is the text '$17 billion' set against the backdrop of a seismic graph. Context - Auckland and Christchurch have been given top priority in the Government's latest national infrastructure plan, with more than seven billion dollars of its $17 billion budget going to the two cities. NZ Council for Infrastructure chief executive Stephen Selwood says hes not surprised at the large amount of funding going to Auckland and Christchurch, saying its clear the Christchurch rebuild will require a major commitment and Aucklands continued growth also requires significant funding. (Source: www.3news.co.nz, 5 July 2011) Quantity: 1 digital cartoon(s).
Extended Direct Analysis (EDA), developed at the University of Canterbury, is an advance on the AISC Direct Analysis method for the analysis of frames subjected to static forces. EDA provides a faster, simple and more rational way to properly consider the second-order effects, initial residual stresses (IRS) and the initial imperfections or steel structures under one directional loading than conventional analysis methods. This research applied the EDA method to quantify the effect of member overstrength on frame behaviour for a single storey frame. Also, the effects of IRS, which were included in the EDA static analysis, but which are not considered explicitly in non-linear seismic analysis, were evaluated in two ways. Firstly, they were considered for simple structures subject to increasing cyclic displacement in different directions. Secondly, incremental dynamic analysis with realistic ground motion was used to quantify the likely effect of IRS in earthquakes. It was found that, contrary to traditional wisdom and practice, greater member strengths can result in lower frame strengths for frames under monotonic lateral loading. The structural lateral capacity of the overstrength case was reduced by 6% compared to the case using the dependable member strengths. Also, it resulted significantly different in member demands. Therefore, it is recommended that when either plastic analysis or EDA is used, that both upper and lower bounds on the likely member strength should be considered to determine the total frame strength and the member demands. Results of push-pull analysis under displacement control showed that for IRS ratio, gamma < 0.5 and axial compressive force ratio, N*/Ns, up to 0.5, IRS did affect the structural behaviour in the first half cycle. However, the behavior in the later cycles was not significantly affected. It also showed that the effect of initial residual stresses in the frame was less significant than for the column alone when the column was subjected to similar axial compressive force. The incremental dynamic analysis results from both cantilever column and the three-storey steel frame showed that by increasing gamma = 0 to 0.5, the effect of IRS on seismic responses, based on the 50% confidence level, was less than 3% for N*/Ns, up to 0.5.
As part of the 'Project Masonry' Recovery Project funded by the New Zealand Natural Hazards Research Platform, commencing in March 2011, an international team of researchers was deployed to document and interpret the observed earthquake damage to masonry buildings and to churches as a result of the 22nd February 2011 Christchurch earthquake. The study focused on investigating commonly encountered failure patterns and collapse mechanisms. A brief summary of activities undertaken is presented, detailing the observations that were made on the performance of and the deficiencies that contributed to the damage to approximately 650 inspected unreinforced clay brick masonry (URM) buildings, to 90 unreinforced stone masonry buildings, to 342 reinforced concrete masonry (RCM) buildings, to 112 churches in the Canterbury region, and to just under 1100 residential dwellings having external masonry veneer cladding. In addition, details are provided of retrofit techniques that were implemented within relevant Christchurch URM buildings prior to the 22nd February earthquake and brief suggestions are provided regarding appropriate seismic retrofit and remediation techniques for stone masonry buildings. http://www.nzsee.org.nz/publications/nzsee-quarterly-bulletin/
This paper outlines the deconstruction, redesign and reconstruction of a 2 storey timber building at the University of Canterbury, in Christchurch, New Zealand. The building consists of post tensioned timber frames and walls for lateral and gravity resistance, and timber concrete composite flooring. Originally a test specimen, the structure was subjected to extreme lateral displacements in the University structural testing laboratory. This large scale test of the structural form showed that post tensioned timber can withstand high levels of drift with little to no structural damage in addition to displaying full recentering characteristics with no residual displacements, a significant contributor to post earthquake cost. The building subsequently has been dismantled and reconstructed as offices for the Structural Timber Innovation Company (STIC). In doing this over 90% of the materials have been recycled which further enhances the sustainability of this construction system. The paper outlines the necessary steps to convert the structure from a test specimen into a functioning office building with minimal wastage and sufficient seismic resistance. The feasibility of recycling the structural system is examined using the key indicators of cost and time.
Text top left reads 'Downsizemic activity' and a seismic graph zigzags wildly but gradually tails off into the words 'Interest rates' which take a serious downwards trend. Context - The Christchurch earthquakes of 4 September 2010 and 22 February 2011 which have had an impact on an already stagnating economy. The Reserve Bank has made a relatively large 50-point cut in its benchmark interest rate, the Official Cash Rate (from 3% to 2.5 per cent). Critics say that inflation is already running unacceptably high and there is a threat of much higher inflation in a year or two when the rebuilding of Christchurch begins to put pressure on limited resources. The Reserve Bank acknowledged these factors, but it has chosen instead to focus on the immediate impact of the earthquake on the economy and particularly on all-important business and consumer sentiment. (Press editorial 12 March 2011) Quantity: 1 digital cartoon(s).
The cartoon shows the Christchurch Anglican Cathedral tower in ruins and without its steeple. Above the drawing is the date '22.2.11'. A second version shows a huge magnitude 6.3 earthquake tremor on a seismic graph on top of which is the date '22.2.11'. Context - On 22 February 2011 at 12:51 pm (NZDT), Christchurch experienced a major magnitude 6.3 earthquake, which resulted in severe damage and many casualties. A National State of Emergency has been declared. The cathedral tower has collapsed and there has been devastating damage to the remaining structure. The Cathedral is one of around six sites of extreme concern around the city where many are believed to still be trapped. This earthquake followed on from an original magnitude 7.1 earthquake on 4 September 2010 which did far less damage and in which no-one died. Two versions of this cartoon are available Quantity: 2 digital cartoon(s).
The M7.1 Darfield earthquake shook the town of Christchurch (New Zealand) in the early morning on Saturday 4th September 2010 and caused damage to a number of heritage unreinforced masonry buildings. No fatalities were reported directly linked to the earthquake, but the damage to important heritage buildings was the most extensive to have occurred since the 1931 Hawke‟s Bay earthquake. In general, the nature of damage was consistent with observations previously made on the seismic performance of unreinforced masonry buildings in large earthquakes, with aspects such as toppled chimneys and parapets, failure of gables and poorly secured face-loaded walls, and in-plane damage to masonry frames all being extensively documented. This report on the performance of the unreinforced masonry buildings in the 2010 Darfield earthquake provides details on typical building characteristics, a review of damage statistics obtained by interrogating the building assessment database that was compiled in association with post-earthquake building inspections, and a review of the characteristic failure modes that were observed.