SDOT: Upper bridge repair: Tensioning of steel cables in progress

Information from the Seattle Department of Transportation

In June 2022, we completed the assembly of cable conduits and temporary supports for the post-tensioning system. Cable trays create a system to hold and protect steel cables used for post-tensioning. We have also completed the initial phase of carbon fiber packaging. Watch our latest progress video to learn more.

This week marked major progress for the final repairs of the West Seattle Bridge. After completing the installation of the nearly 250,000 feet of steel cable needed for the new post-tensioning system inside the bridge last week, we began the process of tightening the post-tensioning system by pulling on cables with hydraulic equipment. This type of equipment is mounted on the steel cables and uses a high pressure liquid to pull and tighten each cable tightly.

We completed the first phase of the tensioning process earlier this week by tightening each steel cable to approximately 20% of its final tension strength. We tighten each cable in a specific sequence to ensure the deck structure is compressed evenly and consistently throughout the process.

We now increase the tension so that the steel cables are stretched to 100% of their final tension strength.

Once the cables are fully tensioned, we will begin our final phase of epoxy crack injection and carbon fiber wrap.

Hydraulic SDOT

We use hydraulic equipment to tighten each steel cable, as shown in this photo above. Once the cables are fully tensioned, the concrete of the bridge structure will be stronger than ever.

steel cables

As the steel cables are pulled through the hydraulic equipment, we measure them to ensure the bridge structure is compressed evenly and consistently throughout the process.

We also completed other maintenance work on and near the bridge this week. This included putting in place the replacement sign structures, demolishing and replacing the concrete panels at the western approach to the bridge structure, and continuing the concrete pours on the Fauntleroy Expressway.

Construction in West Seattle and South Park this weekend

Saturday and Sunday we will be repairing sidewalks and building ramps on 37th Ave SW and Fauntleroy Way SW. We will start working at 8:00 a.m. and end at 4:00 p.m. During this work, we will have to close a northbound traffic lane. Drivers should anticipate delays when traveling through the area.

Also on Saturday and Sunday from 7:00 a.m. to 5:00 p.m., we will be paving the east side of 35th Ave SW between SW Morgan St and SW Holly St. Traffic impacts include one lane closure in each direction . Parking will also be limited while we complete this work. Please navigate the area with caution.

Paving of Myers Way

Last weekend we completed the paving project on Myers Way S near the intersection with Olson Pl SW.

Saturday we will continue to update the traffic lights on 7th Ave S and S Cloverdale St in South Park. We do not anticipate significant impacts to travelers as we will be working from the side street on 7th Ave S.

Question of the Week: What’s the best way to stay informed about the West Seattle Bridge reopening schedule?

The best way to stay informed about the West Seattle Bridge reopening schedule is to sign up for our weekly Friday emails, which if you’re reading this you probably already have! Share this registration link via email with a friend, neighbor, colleague, family member, or anyone you think would like to stay up to date on the West Seattle Bridge program.

You can also stay up to date by visiting the SDOT blog, following SDOT on Facebook and Twitter, or reading the “What’s Happening Now” sections of our web pages.

About Dianne Stinson

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