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Earthquake-safe rocking walls tested by researchers

New Zealand researchers are testing advanced technology that aims to keep walls up during strong earthquakes.

Auckland University researchers are shake-testing a new concrete wall design to better withstand a strong quake. Source: 1 NEWS

They're called rocking walls, and Auckland University researchers are testing them to see how much shaking they can take to avoid repeats of Christchurch's wipespread devastation.

Traditional concrete walls, reinforced with steel, can be ripped apart in a strong earthquake.

In the new rocking walls the steel reinforcing isn't bonded to the concrete, instead it passes through holes and is tightened at each end. The high tension fastening turns each steel wire into what the researchers call a tendon.

"It sort of acts like an elastic band during an earthquake. When an earthquake comes along the wall will rock and then self centre," says Kimberly Twigden, Auckland University engineering PhD student.

Rebuilding Christchurch with the new rocking walls wouldn't just make the city safer, it would also be cheaper if another strong earthquake did hit in the future.

"Parts that are damaged can be easily replaced so you get to a point after a large earthquake where repairs are relatively straightforward, you don't require buildings to be shut down," says Rick Henry, an engineering lecturer at Auckland University.

The current scale model is holding up weights of four tonnes and Ms Twigden says it is being subjected to some serious shaking.

"The earthquakes we're running through are up to a one in 2000 year earthquake, which is something we might expect in Wellington one day," she says.

Rocking walls are already in use in some cities around the world.