Liquefaction-induced lateral spreading during earthquakes poses a significant hazard to the built environment, as observed in Christchurch during the 2010 to 2011 Canterbury Earthquake Sequence (CES). It is critical that geotechnical earthquake engineers are able to adequately predict both the spatial extent of lateral spreads and magnitudes of associated ground movements for design purposes. Published empirical and semi-empirical models for predicting lateral spread displacements have been shown to vary by a factor of <0.5 to >2 from those measured in parts of Christchurch during CES. Comprehensive post- CES lateral spreading studies have clearly indicated that the spatial distribution of the horizontal displacements and extent of lateral spreading along the Avon River in eastern Christchurch were strongly influenced by geologic, stratigraphic and topographic features.
In 2010 and 2011 a series of earthquakes hit the central region of Canterbury, New Zealand, triggering widespread and damaging liquefaction in the area of Christchurch. Liquefaction occurred in natural clean sand deposits, but also in silty (fines-containing) sand deposits of fluvial origin. Comprehensive research efforts have been subsequently undertaken to identify key factors that influenced liquefaction triggering and severity of its manifestation. This research aims at evaluating the effects of fines content, fabric and layered structure on the cyclic undrained response of silty soils from Christchurch using Direct Simple Shear (DSS) tests. This poster outlines preliminary calibration and verification DSS tests performed on a clean sand to ensure reliability of testing procedures before these are applied to Christchurch soils.
essential systems upon which the well-being and functioning of societies depend. They deliver a service or a good to the population using a network, a combination of spatially-distributed links and nodes. As they are interconnected, network elements’ functionality is also interdependent. In case of a failure of one component, many others could be momentarily brought out-of-service. Further problems arise for buried infrastructure when it comes to buried infrastructure in earthquake and liquefaction-prone areas for the following reasons: • Technically more demanding inspections than those required for surface horizontal infrastructure • Infrastructure subject to both permanent ground displacement and transient ground deformation • Increase in network maintenance costs (i.e. deterioration due to ageing material and seismic hazard) These challenges suggest careful studies on network resilience will yield significant benefits. For these reasons, the potable water network of Christchurch city (Figure 1) has been selected for its well-characterized topology and its extensive repair dataset.
We present ground motion simulations of the Porters Pass (PP) fault in the Canterbury region of New Zealand; a major active source near Christchurch city. The active segment of the PP fault has an inferred length of 82 km and a mostly strike-slip sense of movement. The PP fault slip makes up approximately 10% of the total 37 mm/yr margin-parallel plate motion and also comprises a significant proportion of the total strain budget in regional tectonics. Given that the closest segment of the fault is less than 45 km from Christchurch city, the PP fault is crucial for accurate earthquake hazard assessment for this major population centre. We have employed the hybrid simulation methodology of Graves and Pitarka (2010, 2015), which combines low (f<1 Hz) and high (f>1 Hz) frequencies into a broadband spectrum. We have used validations from three moderate magnitude events (𝑀𝑤4.6 Sept 04, 2010; 𝑀𝑤4.6 Nov 06, 2010; 𝑀𝑤4.9 Apr 29, 2011) to build confidence for the 𝑀𝑤 > 7 PP simulations. Thus far, our simulations include multiple rupture scenarios which test the impacts of hypocentre location and the finite-fault stochastic rupture representation of the source itself. In particular, we have identified the need to use location-specific 1D 𝑉𝑠/𝑉𝑝 models for the high frequency part of the simulations to better match observations.
As a result of the Canterbury earthquakes, over 60% of the concrete buildings in the Christchurch Central Business District have been demolished. This experience has highlighted the need to provide guidance on the residual capacity and repairability of earthquake-damaged concrete buildings. Experience from 2010 Chile indicates that it is possible to repair severely damaged concrete elements (see photo at right), although limited testing has been performed on such repaired components. The first phase of this project is focused on the performance of two lightly-reinforced concrete walls that are being repaired and re-tested after damage sustained during previous testing.
Heathcote Valley school strong motion station (HVSC) consistently recorded ground motions with higher intensities than nearby stations during the 2010-2011 Canterbury earthquakes. For example, as shown in Figure 1, for the 22 February 2011 Christchurch earthquake, peak ground acceleration at HVSC reached 1.4 g (horizontal) and 2 g (vertical), the largest ever recorded in New Zealand. Strong amplification of ground motions is expected at Heathcote Valley due to: 1) the high impedance contrast at the soil-rock interface, and 2) the interference of incident and surface waves within the valley. However, both conventional empirical ground motion prediction equations (GMPE) and the physics-based large scale ground motions simulations (with empirical site response) are ineffective in predicting such amplification due to their respective inherent limitations.
A pdf copy of a PowerPoint presentation made for the Water Services Association of Australia conference, about SCIRT's approach to asset investigation after the Canterbury earthquakes of 2010 and 2011.
A video of the Christchurch Mayor Lianne Dalziel's opening address at the 2016 People in Disasters Conference.
A document which contains the slide notes to go with the PowerPoint presentation made for the Water Services Association of Australia conference.
A media release which outlines the outcomes of the campaign to reclaim Christchurch cones.
A report which details the archaeological investigations carried out during the course of SCIRT project 11185, water main renewal work on Manchester Street.
A report which details the archaeological investigations carried out during the course of SCIRT projects 11115 and 11159, wastewater renewal work and storm water repair work on Ferry Road.
A presentation which was given as part of the FME Desktop World Tour in 2015 in Christchurch.
A document which summarises each winning Bill Perry Safety Award submission.
A video which describes the history of the bridge and SCIRT's repair methodology.
The SCIRT Health and Safety Policy, revised in February 2016.
A PDF version of the memento book created for those who contributed to the SCIRT programme.
A report reviewing pipe installation specifications and recommending alternatives that could improve standard specifications.
A report created by the University of Canterbury Quake Centre and the University of Auckland, funded by the Building Research Levy. It shows how an innovation process was initiated and managed throughout the rebuilding of the horizontal infrastructure after the Canterbury earthquakes.
A diagram which illustrates the numbers of people trained to July 2016.
A document which outlines the communication strategy behind the Lonely Cone campaign.
A copy of the award application for the Canterbury Heritage Awards 2016.
A document which outlines the purpose and processes associated with ECI at SCIRT.
A document which describes SCIRT's Geographic Information System (GIS) Viewer.
A plan which outlined the scope, approach and key deliverables for communications and stakeholder engagement for SCIRT.
A public relations flyer which outlines the repairs undertaken on the Gloucester Street bridge.
A management plan which describes how SCIRT will coordinate utility authorities and utility relocations.
A document which describes the establishment of the SCIRT Women in Construction (SWIC) group and its achievements.
A document containing the research questions asked by Opinions Market Research Ltd when carrying out telephone surveys about SCIRT work.
A document which sets out the terms of reference for SCIRT's Safety Leadership Group.
