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Remains of Worlds Longest Floating Bridge

In 1963, the Washington State Department of Transportation achieved a Guinness World Record when it constructed the worlds longest floating bridge which connected the cities of Bellevue and Seattle. The SR 520 Bridge, completed in August 1963 and measuring 2.39 miles in length, with a floating section stretching for almost 1.5 miles.

The bridge carried four lanes of traffic, separated by a curb that was later replaced with a simple Jersey barrier. At the center was a drawspan that opened for large vessels traversing the lake.

After serving Washington State for over 50 years it had begun to show it's age. The original Evergreen Point Floating Bridge was designed before the implementation of modern earthquake engineering standards, with vulnerabilities in its hollow support structures that could have failed in a major earthquake. Additionally, vibrations caused by storm surges and strong winds were able to compromise the aging drawspan, anchor cables and pontoons, which could lead to structural failure in a major storm. This required the bridge to close to traffic during sustained wind gusts of 50 miles per hour or higher for more than 15 minutes.

Although the original bridge carried two lanes of traffic in each direction, it did not include shoulders or pedestrian and bicycle infrastructure. The lack of a shoulder led to traffic congestion in the event of an accident, which would block one or two lanes in a given direction and block emergency services from accessing the bridge.

The new bridge was dedicated on April 2, 2016, and was certified by Guinness World Records as the new world's longest floating bridge at a length of 7,708.49 feet long, 130 feet longer than the bridge it replaced.

The bridge was deconstructed into sections 110 metres long with 25-centimetre thick walls and pontoons. It was supposed to be floated to an industrial site in Kenmore for disposal and recycling.However, the city rejected the plan, citing the possible release of toxins in the pontoon's concrete. The sections were acquired by True North Operations Group with the goal of re-purposing the pontoons as temporary or permanent docks or off-loading facilities, piers or offshore storage.

Four years later, the majority of the pontoons continue to sit unused in the Pitt River.

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