[M II A II R II K]

Norway is getting a floating suspension bridge tethered to the bottom of the sea — and it could change the way we make bridges

https://www.businessinsider.com/norw...a-floor-2018-4

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- Bridge engineer Ian Firth discussed the 3-mile-long bridge, which will cross a long and deep Norwegian fjord known as Bjørnafjord, during a talk at this week's TED Conference in Vancouver, Canada. Bridge foundations in deep water can be incredibly expensive. But the Bjørnafjord bridge gets around that by floating. — The Bjørnafjord bridge will stand on floating pontoons that will be tethered to the seabed. In order to create stability, the tops of the bridge's towers will be tied together. A similar floating design has been used for oil platforms in the past — but never for multi-span suspension bridges until now.

- There is still a long way to go before this kind of bridge technology becomes commonplace, however. The Bjørnafjord bridge's materials are well understood, but there are construction challenges, including the building and maintenance of the top cables. The bridge will actually last longer than the cables — which support the bridge — so replacements will have to be made available. — "Nobody wants to do something that's been unproven and yet everybody wants to be the first," Firth said. "Once we've sold the technical challenges, it will reach that sweet spot where the economics become something that's doable."

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