West Seattle Bridge: A look at construction so far as reopening date looms
SEATTLE - The West Seattle Bridge remains on track for a Sept. 18 reopening date, Seattle Department of Transportation officials said on Thursday.
The bridge was shut down by Mayor Jenny Durkan on March 23, 2020 after engineers could not vouch for the bridge's structural integrity.
FOX 13 was able to take a look inside the inner sanctum of the hollow bridge where the major structural work had been completed on the $47 million repair.
Long steel cylinders full of steel cables are tightening the bridge in the key areas where cracks in the concrete structure started expanding rapidly in 2020. Multiple steel tendons line the floor into the cavernous bridge, each capable of 280,000 pounds of pulling pressure.
Four longer steel cylinders run nearly the entire length of the bridge. Each one contains 40 strands of steel wiring and each has the pulling strength of 1,000,000 pounds of pressure.
"It is compressing the bridge so that those cracks that had opened up are now squeezed shut, they are sealed with epoxy and they have a carbon fiber wrap that is applied to make sure they don’t open up in the future," said Adam Dour, the project manager for Kramer North America, the company responsible for strengthening the bridge.
There are still hairline cracks in the side walls of the hollow core. The larger cracks, some that began to form 15 years ago, have been filled with epoxy.
"These are more of a structural concern than the original hairline cracks," said Greg Banks, the chief bridge engineer for the project.
The millions of pounds of pressure to tighten the bridge has also improved its strength.
West Seattle Bridge expected to reopen on Sept. 18
As crews continue to work on the final stages of the West Seattle Bridge repairs, officials with the Seattle Department of Transportation announced on Thursday that the structure is now expected to reopen on Sept. 18.
"The rehabilitation tension repairs are designed to accommodate all the lanes of traffic currently on the bridge," said Dour. "The weight added by the cars is not a significant portion of the weight of the entire structure. 80% of the weight of this structure is the structure itself.
When it opens, it will not be a slow opening with just one or two lanes of vehicles.
"In the early days, we were thinking that might be the right way to go but no, we are not going to approach it that way -- we are just going to open the bridge," said Heather Marx, the Project Lead for the Seattle Department of Transportation.
The make sure the bridge performs as expected, a series of sensors were placed in areas that have shown cracking and will monitor its every move.
"The bridge moves when it reacts to the environment it goes up and down and everything and we've been studying that for a couple of years," said Greg Banks, the lead engineer on the repairs. "So if the movement is different from what we've seen, it will tell us something is happening and we'll come out and look at it."
Immediately after the bridge closed, restrictions were placed on when and who could use the best alternative to cross the Duwamish River – the Lower West Seattle Swing Bridge.
Using the lower bridge rather than a lengthy detour could save drivers 45 minutes.
Photo enforcement cameras were eventually installed and unauthorized drivers would receive a $75 citation. Those restrictions and the cameras are going away when the bridge reopens.
"Once this high bridge opens, you'll be able to drive freely on the low bridge with no photo enforcement and no restrictions," said Marx.
Load testing on the bridge will be getting underway next week. If the bridge fails the test, the opening could be delayed, according to Marx, but officials say they don’t expect that to happen.