August 21, 2020

Sound Transit finishes Bellevue East Link tunnel

Photos from Sound Transit [enlarge]

The tunnel comes out at Bellevue Downtown Station.

[enlarge]

The tunnel is nearly 28 feet tall and 34 feet wide, with a center wall separating the tracks.

Even with delays caused by the pandemic, Atkinson Construction was able to keep the East Link light rail tunnel in Bellevue on schedule. Sound Transit on Wednesday marked the completion of the nearly 2,000-foot-long tunnel after three years of construction.

When East Link opens in 2023, the tunnel will connect the East Main and Bellevue Downtown stations. Eastbound trains will enter the tunnel north of the East Main station at 112th Avenue Southeast and Main Street and travel under 110th Avenue Northeast, turning east near Northeast Sixth Street to emerge at the future Bellevue Downtown Station.

Atkinson used the sequential excavation method to build the tunnel, using track-mounted excavators and cutting equipment to remove soil in small sections, and supporting excavated areas with shotcrete. Crews then applied waterproofing, and constructed the center wall and final concrete lining.

The tunnel is nearly 28 feet tall and 34 feet wide, with a center wall separating the tracks. A total of 72,000 cubic yards of soil was excavated — equal to a football field dug down 43 feet.

By adapting to different ground conditions, Atkinson was able to complete excavation five months earlier than expected, which helped keep the project on schedule.

Atkinson is teaming up with Stacy and Witbeck on a separate contract for East Link that builds the stations and track that runs from downtown Bellevue to the Spring District. This work includes track and systems installations in the tunnel.

“East Link's opening in 2023 will be preceded in 2021 by Northgate Link and in 2022 by the Tacoma Link Hilltop Extension,” said Sound Transit CEO Peter Rogoff in a news release. “One year later, in 2024, we will extend Link to downtown Redmond, Lynnwood and Federal Way. They will more than double our current reach and simultaneously help fuel our region's economic recovery.”

East Link will extend light rail 14 miles from downtown Seattle to downtown Bellevue and the Overlake area of Redmond via Interstate 90, with 10 stations. In 2024, Link light rail will extend another 3.4 miles east to new stations in southeast Redmond and downtown Redmond.