Seattle

SDOT reaches intermediate milestone on repairs of West Seattle Bridge – Seattle, Washington

Seattle, Washington 2021-07-14 17:32:13 –

West Seattle skyscraper. The Seattle Department of Transportation states that it has reached an intermediate milestone in the repair of the West Seattle skyscraper. The bridge was closed from March 2020 after engineers saw a dangerous crack endangering the bridge.

Photo provider: SDOT

Information from the Seattle Department of Transportation

We have reached an intermediate design internal milestone in the final stages of West Seattle high-rise bridge (Takahashi) repair. This is the latest in several important milestones reached on time in an effort to reopen the bridge in mid-2022. This reflects an aggressive schedule for recovering trips to the bridge.

In March 2020, a high bridge was closed to protect public safety after city technicians discovered rapidly growing cracks in multiple locations. We immediately set about emergency stabilization work, including installing a 10-mile steel cable inside the bridge, repairing deformed bearings in the Pier 18 support structure, and wrapping the structure in carbon fiber in multiple locations. It was. These emergency measures We managed to prevent the cracks from growing and left the bridge upright, but additional work is needed to further strengthen the bridge to support the weight and stress of daily traffic.

After these repairs were completed, extensive monitoring was carried out to ensure that the bridge was functioning as expected, while designing the bridge for reuse.

The second final stage of repair is built on the same proven method, including filling epoxy injection cracks, post tension, and wrapping carbon fiber in the mainspun. This phase also includes strengthening the side spans of the bridge (between peers 15 and 16 and between peers 17 and 18 of the bridge columns).

In the first stage of stabilization of the high bridge, a temporary work platform was set up under the bridge.
Photo courtesy of Tim Durkan

Our team is confident that these repair methods will succeed in getting the bridge back into service on time, but that doesn’t mean the process is simple. Careful and complex planning is required. Install a temporary work platform in the working Dewarmish channel, mobilize skilled construction workers, and install steel cables and carbon fiber wraps along multiple spans 1,300 feet long and 140 feet high. To procure. bridge.

That’s why we’re excited to see construction contractor Kraemer North America riding under us. Pre-construction contract..

Having submitted these interim design plans, Kraemer’s team is looking for opportunities to scrutinize them, maximize efficiency, and speed up schedules. This means that Kraemer can start contacting the supplier about the custom-made materials needed to complete the repair. They will also attract local talent to repair the bridge as we continue to pursue local labor agreements.

The mid-design milestones were on schedule and we were ready to reach the final design in September. At that time, you can finalize the construction plan with Kraemer and share the details of the construction method and schedule.

Here’s what we now know about the details of Phase 2 rehabilitation:

Schematic diagram of side spans

Cross section of West Seattle Bridge
One cross section of the hollow girder of the bridge (straddling between the stanchions of the bridge). Hollow girders allow our team to access the inside of the box for inspection and maintenance purposes, install utilities and monitoring systems, and repair the bridge.

During Phase 1 stabilization, epoxy injection was attached to the concrete and coated with carbon fiber wrap to slow the spread of cracks in the damaged area. Phase 2 rehabilitation adds carbon fiber wrapping to the center and side spans of the bridge. Adding carbon fiber wrapping to the surface of the bridge works in conjunction with the steel already inside the bridge to increase the strength of the bridge.

Post tension steel cable

Post-tension steel cables are attached to the inside of the bridge’s concrete girders (supports) and tighten the concrete before the vehicle moves over the bridge, allowing the bridge to carry heavier loads. .. It also reinforces the structure of the bridge to prevent further cracking. Phase 1 will install a new post-tension in the center of the bridge’s central span and add post-tension to the side and center spans as part of Phase 2.

Bridge monitor

Since Phase 1 stabilization, we have used intelligent surveillance technology to assess how the bridge responds to repairs. As a precursor to Phase 2 construction, a more sophisticated long-term surveillance system will be installed to allow surveillance to continue after the active bridge is re-accessible.

At the end of this summer, you’ll see the team on the bridge install the first of a new long-term monitor. These monitors monitor the performance of bridges that opened in mid-2022, allowing you to proactively manage this important connection.

As you progress through future milestonesKeep your progress up to date in order to reopen the bridge as quickly and safely as possible.

Here’s what you need to know about repair efforts in case you miss it:

  • Completed in December 2020 Phase 1 stabilization work On the bridge. This work included a proven method designed to prevent further cracking and stabilize the bridge.
  • As we developed Preliminary design of the bridge In the winter of 2021, extensive surveillance was carried out to ensure that the bridge was functioning as expected when the weather changed from cool to warm.
  • This monitoring showed that the bridge was working as expected in the snow in February and the heat in July, completing the intermediate design and promoting the construction contract at the same time, and at the same time proceeding on schedule. is.
  • In May, we announced the selection of construction contractor Kraemer North America. Our decision to involve contractors early in the design process is just one way to speed up the schedule.
  • And in June, we confirmed that Kraemer had a notice (NTP) to continue under the pre-construction contract. Received over $ 11 million in federal grants to fund bridge repair efforts..

Do you have any questions about the work we are doing to reopen the bridge for traffic and manage the traffic while the bridge is closed? Join us for a virtual public conference on July 21st at 5:30 pm. Click here for details and participation..



SDOT reaches intermediate milestone on repairs of West Seattle Bridge Source link SDOT reaches intermediate milestone on repairs of West Seattle Bridge

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