Optimism increasing in ability to fix West Seattle Bridge

Seattle transportation managers are increasingly confident that repairs can make the cracked West Seattle Bridge last for at least 15 more years.

The city would seek to restore six lanes of traffic in 2022, compared to a demolition and replacement that would disrupt travel until 2026 or longer, at greater expense, The Seattle Times reported.

A repair-or-replace decision by Mayor Jenny Durkan isn’t due until at least October, but the Seattle Department of Transportation has revealed some repair possibilities in recent forums and interviews.

Contractors are working to stabilize the bridge by wrapping portions of the cracked concrete girders in carbon fiber. This month, they’ll further strengthen it by stringing groups of steel cables inside the hollow girders. Like a rubber band, those cables will compress the four weak zones where cracks emerged, a method known as post-tensioning.

To make the bridge strong enough to handle 100,000 vehicles a day, a longer and more critical set of steel post-tensioning cables must be strung through the entire 590-foot (180-meter) central span from pier to pier.

It’s been nearly six months since accelerating cracks forced city transportation officials to declare an emergency closure March 23. As people return from COVID-19 quarantines, traffic jams and delays are worsening on detour routes, which is building support for repairs as the quickest remedy.