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Ballinger Way Portal site and construction activities
- Ballinger Way NE near 19th Ave. NE in Shoreline

Construction updates - January 2008 Neighbors may have noticed the trailers with steam rising off of them at this site. These trailers contain freezer units being used in the ground freezing operation at this site (see 'Portal Construction section on this page). The ground is now prepared and excavation of the portal shaft will begin this month. There will be more activity and workers at the site. This phase of construction is expected to be completed early this summer. Previous updates: Ballinger Way July 2007 construction update (PDF file, 260 KB)

For this part of the project, construction is centered at the Ballinger Way Portal in Shoreline, located along Ballinger Way NE, just west of the 19th Ave. NE intersection. There are two main parts to this project:

Brightwater portals and pipelines: The system of pipes that brings wastewater to the treatment plant and treated wastewater to Puget Sound is called the conveyance system. To limit construction at the surface, the conveyance pipelines are being built below ground in tunnels 40 to 440 feet below the surface. Portals are the access shafts where workers, machines, soil, and equipment enter and exit the tunnels during construction.

Tunnel boring machines (TBMs) are being used to build the tunnels. These large machines do their work underground, excavating the tunnel and installing a concrete lining as they go.

The Ballinger Way Portal is a "receiving" portal: TBMs will not be launched from here. Instead, two TBMs - one coming from Point Wells to the west and another from Kenmore - will be pulled from the ground at this portal after completing their work. This means that less work and materials will be needed at the site and for a shorter duration compared to the launching portals.

Portal Construction:
Construction of the Ballinger access shaft began this summer and will take about one-and-a-half years to complete. King County's contractor is using ground freezing to assist in constructing the 25-foot diameter, 200-foot deep TBM retrieval shaft.

Ground freezing involves installing a series of small diameter, deep wells dug around the perimeter of the portal shaft. These wells will be lined and filled with a freezing saltwater brine. The brine is continuously circulated through the wells through above-ground refrigeration units. As the brine circulates, the nearby ground freezes, creating ground support which allows shaft excavation. Equipment will break up and remove the soil from the center of the shaft. Steel, concrete and wood supports will be installed to the wall of the shaft as a liner during excavation. When digging is complete a final concrete portal wall will be built.

When shaft construction is completed in late 2008, the site will be inactive until the two TBMs arrive from Kenmore and Point Wells and are removed from the shaft. TBM removal is expected to be in late 2009. The shaft will then be sealed.

Permanent Facilities:
After all of the underground work is done, the portal shaft will be sealed. An odor control facility will be built. This will be about 300 square feet in area and 15 feet tall. It will be attractively designed and landscaped.

Construction Activities

Portal construction started this summer and is expected to last for about four years.

What you can expect during construction

King County is committed to being a good neighbor and will work to minimize impacts to nearby businesses and residence during construction. At this portal site, there may be times between demolition and portal construction and between portal construction and TBM removal when the site is inactive.

During construction, neighbors may experience increased truck traffic, construction noise, and potential vibrations. To minimize these potential impacts we will implement a traffic management plan approved by the City of Shoreline, control erosion, and make sure that trucks do not track dirt or mud from the site.

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Contact us if you need more information about Brightwater.

King County Brightwater Project

22505 State Route 9
Woodinville, WA 98072-6010

Updated: January 11, 2008