1984 West Seattle Bridge closed March 23, 2020 for 2.5 years after just 36 years of service

(Archived Bridge Hunter; Satellite, the southern bridge)

The 2,607' (795m) long bridge has a main span of 590' (180m). [BridgeHunter]

It has a clearance of 157' (48m). [pauldorpat]

Street View, Jun 2019
[The Spokane Street Bridge, or Low Bridge, is in the background.]

Because it is a high-clearance bridge, it has long approaches.

Street View, Feb 2023

Until this bridge was built, the only access to the West Seattle peninsula from downtown Seattle was a drawbridge.

chron, License: Creative Commons Attribution (CC BY) via Dennis DeBruler

Traffic was so bad on these bridges that "on March 29, 1978, a who’s who of West Seattle launched a campaign to secede from Seattle....A separate West Seattle would become the state’s fourth largest city, with stronger status to secure money for a high bridge to connect with top dog Seattle." But at 2:58am June 11, 1978, the succession effort wasn't needed because a freighter allided with the bridge. "The culprit was the now-legendary three-minute “lack of concentration” of 80-year-old pilot Rolf Neslund, who, bizarrely, later was murdered by his wife." The damage was considered irreparable. After decades of fighting, politicians then quickly found funding for the desired high bridge. [pauldorpat]

The Antonio Chavez freighter that ended the funding controversies for a high bridge.

seattlemet, COURTESY SEATTLE MUNICIPAL ARCHIVES / 73167,
"'His ship was able to do in a few seconds something the city hasn’t been able to do in years….he helped solve a problem that decades of official oratory, committee-forming and money-spending had only turned into a bigger problem.' —Ross Anderson, The Seattle Times, June 27, 1978"
I read that at one time the name of the bridge was the Jeanette Williams Memorial Bridge. This webpage explains that she was the Seattle council member that helped lobby for federal funds. Naming a bridge after a pork-barrel hero is a long-standing tradition for bridges. (e.g. Huey P Long bridges) I wonder why they decided to remove her name.

But there must have been 6 years of congestion on the remaining bridge because the High Bridge did not open until 1984. [BridgeHunter]

Just 36 years later, during the Covid-19 lockdown the bridge was closed for 2.5 years.

whereiamnow
"An inspection in 2014 revealed cracks in the bridge that might have been caused by the Nisqually Earthquake of 2001. (Or was it from a tendency to flutter in high winds?) The bridge was monitored regularly from then on. It was declared unsafe and closed suddenly on March 23, 2020. As of this writing, it's still closed and undergoing repair. Because of a concrete workers' strike, it is uncertain when repairs will be complete and the bridge reopened."

seattlemet, COURTESY CHUN KWAN / SDOT
"The West Seattle Bridge, officially opened in July 1984, closed in March 2020 after the discovery of cracked support girders, which make travel on the 36-year-old structure unsafe."

They discovered that the bridge could not even hold its own deadweight! They had to do stabilization work in 2020 even though they may later decide to tear the whole thing down. The stabilization work involved building work platforms, epoxy injection crack filling, carbon-fiber wrapping, external post tensioning inside the box girders and freeing the lateral bearing at Pier 18.

sdotblog_20200629

From this photo, I thought Pier 18 was on the west side, but from this report, it is on the east side. The plan was to fix that bearing and see if the cracks quit growing.

sdotblog_20200422

This diagram is worth noting because the C bearings show the location of the suspended span for this cantilever bridge. This webpage also has a diagram of the lateral bearing and a detailed explanation of what is wrong.

sdotblog_20200422

sdotblog_20200407
This is an animated gif that shows how the cracks started growing faster and faster.

The 8 months of stabilization effort became Phase I of a repair plan because in Nov 2020 they decided to repair the bridge. Fixing the Pier 18 bearing "helped the bridge find some major stress relief" when completed in Nov 2020. 

sdotblog_20210122

While Phase I was called stabilization, Phase II was called rehabilitation. It was basically doing to the side spans what was done to the central span and do more carbon-fiber wrapping of the central span.

seattle

They expect this repair to last until 2060. But they planned how to replace it anyhow in case they are wrong.

"Once repaired, the lifespan of the bridge is estimated to be between 15 to 45 years." The repairs of this bridge and the Low Bridge cost federal taxpayers $11.2m. [seattlepi]

That lifespan estimate range implies that they really don't know how long it will last.