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West Seattle is about to lose one of its two bridges to downtown. The Lower Spokane Street Bridge will close for about a week, starting this weekend.

A swing bridge isn’t any good if it can’t swing, and the Lower Spokane Street Bridge swings about 1,500 times a year, or about four times a day, to let boats travel along the Duwamish River to Elliott Bay.

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There are two giant turn cylinders inside the bridge, and the Seattle Department of Transportation found damage to one in December.  “On one of the cylinders, which basically turns the bridge and rotates it to open and close position, the seals had leaked, and that resulted in the removal of that cylinder to be overhauled,” the Seattle Department of Transportation’s Kit Loo said.

That . It shut down the low bridge for several weeks at the start of the year. Now it’s time to put it back in.

“We’ve essentially overhauled that cylinder that was down and pulled out, and what we’re planning to do is reinstall that overhauled cylinder this upcoming week and then remove the second one to have it refurbished,” the SDOT interim director of roadway structures, Loo said.

The bridge was designed to open and close with just one functional cylinder. The cylinders had never been removed when workers started the job last time, so he said it took several weeks to make it happen.

“It was a learning process to understand how you move a 20,000-pound item down from 20 feet up in the air into a cradle and move it out that pier house with a really constrained space,” Loo said.

Loo said they learned a lot from that first removal that’s why this upcoming closure is only expected to take about a week because it will take them, “two to three days per cylinder in order to do the operations.” The time is also budgeted to test the bridge and make sure that everything is working correctly.

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The bridge will remain in the open position between Saturday, Oct. 7 and Saturday, Oct. 14. This is expected to cause delays, especially into the Port of Seattle.

“We have been coordinating with the Port of Seattle relating to truck movement into Terminal 5, so they’re aware of some slight changes in terms of how their trucks are going into that terminal,” Loo said. “There’ll be utilized in the high bridge.”

The high bridge is your primary alternate as well. You should expect heavy eastbound congestion near I-5 during the commute next week.

This is expected to have a bigger impact on bike commuters and pedestrians. They will have no access to the bridge either.

SDOT is providing a day who need help completing their trips.

Check out more of Chris’ Chokepoints.