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The SR 99 tunnel contract you’ve never heard of

You may have noticed more construction along State Route 99, just north of the Battery Street Tunnel. That work is part of the SR 99 Tunnel Project, but it has its own name – the North Access Project. It’s also being built under a completely different contract than the one we have with Seattle Tunnel Partners, the contracting team responsible for most of the tunnel work. A map of major contracts within the program can be found here (pdf 1.1 Mb).

Our contractor for the North Access Project, Guy F. Atkinson Construction, is busy building the connections between the future SR 99 tunnel and Aurora Avenue North, as well as new on- and off-ramps at Republican Street. This rendering gives you an idea of what the area will look like when the tunnel opens to drivers.

Initially, crews are installing piles and building support walls before excavation of the area can begin. After that, permanent walls will be built to enclose the northbound roadway as it exits the tunnel.

SR 99 is not only a highway for cars and transit, but also hides a network of utilities below its surface. These utilities must be moved before crews rebuild SR 99 in this area and link it to the tunnel. Atkinson is busy at work along Harrison Street and Dexter Avenue North installing sewer, water and electrical lines. Our north end page will have the latest information about this work as it progresses.

You’ve also probably noticed that our crews aren’t the only ones working in the area. Stay tuned for a major milestone as our partners at the Seattle Department of Transportation transition to two-way traffic on Mercer Street and officially say farewell to Broad Street, which will permanently close in June. After that, our crews will fill in the former Broad Street roadway. We’ll provide more information on closures of SR 99 planned for later this summer to rebuild the SR 99 bridge over Broad Street.