In an earthquake event it will move independently of the building, taking much of the impact, while the main Te Papa “rolls with the punches”, experiencing a longer but gentler motion. Te Papa’s base isolation system takes the form of 152 flexible bearings, described as a “rubber-and-steel sandwich with a core of lead”, that sit between the main building and the concrete slab of its foundation. Examples include Te Papa museum in Wellington, Parliament House, the William Clayton building in Wellington and Christchurch Women’s Hospital. Many important buildings in New Zealand have been built with base isolation. There are various techniques to create base isolation, generally using rubber bearings, friction bearings, ball bearings and spring systems. The base isolation takes the weight of the building, dissipates the seismic forces and allows the foundations to move horizontally – separate from the superstructure. This is a similar idea to car suspension and sees the superstructure of a building decoupled from its substructure, isolating it. One technology to reduce earthquake impacts on buildings, pioneered by New Zealand scientist William Robinson in the 1970s, is what’s known as base isolators or a base isolation system. That was in 2012 to 2013, so they’ve had several years to retrofit those buildings and apply new technologies.”
Some buildings were marked as not complying and needing improvement.
He continued: “In Christchurch, Wellington and probably Auckland too, there was a period where teams were checking which buildings complied and which didn’t. When it comes to the buildings, Codd recalled that “after the Christchurch earthquake, there was a lot of talk about building regulations and how important they are”. It is “self-cleaning” because the structure’s elasticity is enough to use the falling rocks’ kinetic energy to bounce them into a safe zone – off the road. The one designed and installed for this location, following detailed rock fall modelling, is 104m long and is the first of its kind in the southern hemisphere. To combat this, the option of a self-cleaning rockfall canopy was decided to be the best mitigation for the scenario. One particular stretch of the road, below a sheer 90m high cliff face, has continued to experience dangerous rock falls since, which can damage the road – or worse. The transport corridor north and south of Kaikōura suffered extensive damage and was inundated by numerous rockfalls and more than 750,000m 3 of debris from 85 landslides. Meanwhile, one critical piece of infrastructure that was damaged in the 2016 Kaikōura quake was State Highway 1, the country’s longest and most used road. Routes will have been devised for the machinery and plant needed for repair operations to get to where they are needed.” “They know which roads would be affected, which lifeline infrastructure would be affected and then respond to them. “I know the local authorities on the Kapiti Coast, where this quake happened, will have resilience plans in place that will kick into action,” Codd said. The strategy for utilising this access is also part of building resilience. Construction of the NZ$1.25bn (£650M) road started in 2014 and was completed in 2022. This has seen them construct the Transmission Gully Motorway, a new 27km road that stretches past Wellington with the express purpose of improving safety and offering better access. To combat this, Waka Kotahi NZ Transport Agency has invested money into improving resilience of the roads and access for people, resources and materials in and out of the city. “There were only a few ways in, so there was a risk of it becoming isolated in a big earthquake.” “Wellington is a very different city to Christchurch, it’s got a higher population and, geographically, it’s a little bit more isolated,” he said. He said that Wellington – the nearest big city to this week’s earthquake – was previously in a particularly vulnerable position. Progress since the country's 2011 Christchurch earthquake, with a magnitude of 6.3, and the 2016 Kaikōura earthquake, which had a magnitude of 7.8, shows where New Zealand can – and has – improved in its response to massive weather events.Īecom associate director in ground engineering Jamie Codd moved to New Zealand in 2011, after the main Christchurch earthquake. New Zealand’s North Island was struck by a 6.1 magnitude offshore earthquake yesterday, coming shortly after the nation’s most destructive cyclone in decades, but the infrastructure and resilience systems are in place to cope with it more effectively than a few years ago, according to a former resident and chartered geologist.
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