Work begins to stabilize West Seattle Bridge and determine its eventual fate
The Seattle Department of Transportation is beginning work to stabilize the West Seattle Bridge, and prepare it for its yet-to-be determined fate.
Before a decision can be made over whether to fully repair or demolish the span, the bridge needs to be stabilized, first by attaching movable work platforms to its underside. Those platforms will let workers to access the cracked areas of the bridge.
Once crews can safely access those areas, they’ll begin work to wrap sections with carbon fiber-reinforced polymer and “post-tensioning tendons,” before releasing bearings at Pier 18. This work could begin as soon as late-July. That initial process will take roughly 10 weeks.
All this constitutes a process SDOT describes as “a necessary next step toward either repairing the bridge or preparing it for demolition and replacement of some kind.”
“Though our recent analysis indicates that repairing the West Seattle High-Rise Bridge may be possible, we still do not know how much repairs would cost, how long they would take, how many lanes could be restored, and whether repairs would last long enough to be a worthwhile investment,” SDOT said in a recent blog post.
As of Tuesday, a community task force of 30-plus members has met three times to weigh in on the future of the bridge. The group has prepped for a variety of possible scenarios, including one where the bridge could inadvertently collapse under its own weight before fixes can be made.
Engineering firm WSP recently completed a failure analysis of the West Seattle Bridge, which suggests a partial collapse is a more likely scenario than the cracks just stopping. That said, it believes the city can minimize the risk by taking a series of preventative measures, all of which are already underway.