Stuffed to the grates: filling complete in Seattle’s Battery Street Tunnel

Posted on Oct 5 2020 9:56 AM

Contractor crews working on Battery Street in Seattle completed a major milestone in the rebuilding of SR 99 through Seattle. And it’s possible nobody walking or driving nearby even noticed. In late September, crews completed the filling of the Battery Street Tunnel.

The Battery Street Tunnel once carried SR 99 between Aurora Avenue North and the Alaskan Way Viaduct. After the SR 99 tunnel opened in February 2019, crews began methodically removing the old tunnel’s mechanical and electrical systems, installing new utilities, and filling the structure. Much of the Battery Street Tunnel was filled with recycled concrete from the demolished Alaskan Way Viaduct. The final seven feet was filled with lightweight concrete pumped through ventilation grates along Battery Street. You can see photos of this process on our Flickr page

Two photos of of the same view of the Battery Street Tunnel entrance. In the top photo, traffic drives in and out. In the bottom photo, the space where the lanes had been is a dirt slope.

Above: A before-and-after view of the Battery Street Tunnel's south portal.

Through the rest of the year, contractor crews will continue their work along Battery Street, building ADA ramps at each intersection, removing and paving over the tunnel’s ventilation grates and fan boxes, and installing new lighting. The Battery Street Tunnel’s south portal will be also be turned into a slope and seeded with grass, then handed over to the City of Seattle.

Seventh Avenue North work also wrapping up

At the north end of the old Battery Street Tunnel, construction work is almost complete. The trench of highway lanes into and out of the tunnel that once prevented east-west travel between Denny Way and Mercer Street is now Seventh Avenue North. This new, three-block-long roadway offers bus lanes to help transit travel times, new signalized intersections for safe east-west crossings, and will support future bicycle and pedestrian corridor improvements along Thomas Street. The work has reconnected the South Lake Union and Uptown neighborhoods, as you can see in this video.

Although the project is nearly done, construction barrels will remain visible along Seventh Avenue North into early next year when a signal pole for the Denny Way intersection is expected to be installed and turned on.

What remains for the Alaskan Way Viaduct Replacement Program

The program to replace the Alaskan Way Viaduct has involved 30 separate projects. When the North Surface Streets and Battery Street Tunnel work concludes, that previously long checklist will be down to just two: rebuilding Alaskan Way (the project overseen and managed by City of Seattle’s Office of the Waterfront), and the South Access Surface Streets Connections project near Seattle’s stadiums.

The South Access project will complete roadway work between South Atlantic Street and South Dearborn Street in SODO. Sections of street and sidewalk that have been paved temporarily by asphalt will get longer-lasting concrete pavement. We will build a section of a new pedestrian plaza that will link Occidental Avenue to the new pedestrian amenities along Alaskan Way, connecting the waterfront to the stadiums. The project will also build a section of bicycle and pedestrian trail. Work on that project is scheduled to begin in spring 2021.

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