Crews complete post-tensioning work to strengthen West Seattle Bridge

KIRO 7 News Staff
·1 min read

The Seattle Department of Transportation said it has moved closer to reopening the West Seattle Bridge by completing post-tensioning work, which “dramatically” increases the bridge’s strength.

By tightening steel post-tension cables inside the bridge, it reinforces the bridge’s structure and helps to prevent it from cracking, officials said.

“Post-tensioning also helps the bridge better support itself and respond to environmental factors such as weather, vehicle loads, and other external forces.”

In April, construction crews begun the process to install a new post-tensioning system. Structural concrete components were poured for the new foundation. That work ended in May and was followed by workers building and positioning piping for the post-tension cables.

In June, crews pushed steel cables through the pipes, which added nearly 250,000 feet of new post-tensioning cables that spanned the bridge.

Then came the work of tightening the cables, where construction crews “tightened each cable in a specific sequence to ensure that the bridge structure is compressed evenly and consistently throughout the process.”

Now that the cables have been tightened to 100%, crews have other work to focus on, including epoxy injections to fill cracks and carbon-fiber wrapping to add strength to the bridge.

Looking ahead to reopening

  • With post-tensioning complete, the remaining tasks to reopen the West Seattle Bridge are:

  • Complete final epoxy injections and carbon-fiber wrapping

  • Complete cure time for the carbon-fiber wrapping

  • Remove work platforms

  • Load test and inspect the repairs

  • Restore the pavement on the bridge deck

  • Remove construction equipment and get the bridge ready for the public

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