New pavement and walls add shape to the tunnel’s future north portal
At the construction site for the SR 99 tunnel’s north portal, imagining the future is getting easier. While it all looks like one project, north portal construction is comprised of two separate contracts. Roughly everything south of the tunnel entrance near Harrison Street is part of the main tunnel contract being completed by Seattle Tunnel Partners. North of the tunnel entrance, crews working for Atkinson Construction are building the lanes and ramps that will connect the tunnel to SR 99/Aurora Avenue North and nearby streets. Construction started in March at the site on the west side of Aurora Avenue North. As the March photo below shows, the site was little more than a vacant lot. It was hard to imagine a modern freeway in this space.
Fast forward to late October and the landscape has been transformed, sculpted into the raw shape of the future roadway at the tunnel portal, and framed on the left by the curved walls of the portal.
The current view looking northwest from the top of the portal reveals more clues as to the shape of the future SR 99. The southbound lanes are easy to spot on the bottom-left side of the photo. You can see where crews have placed much of the permanent barrier on both sides of the roadway and paved the bottom layer of pavement. The northbound lanes and off-ramp are visible in the bottom-right side of the photo, where the dark green pickup truck and yellow crane are sitting.
After tunnel boring is complete, the future southbound lanes will connect to the 450-foot-long cut-and-cover section of tunnel that will later become the tunnel’s entrance. Shown under construction in the photo below, this part of the tunnel will serve as an access road for crews until the tunnel opens to traffic.
As you can see, there’s still plenty of work to be done, but it’s only a matter of time before the north portal looks like this: