Sound Transit constructing East Link light-rail tunnel in Bellevue one small section at a time

Written by Mischa Wanek-Libman, editor
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Crews are excavating the Bellevue light-rail tunnel at the south portal site at 112th Ave. Northeast and Main.
Sound Transit

A 2,000-linear-foot tunnel that will host light-rail service in Bellevue, Wash., as part of Sound Transit's East Link, is now under construction.

The tunnel will be approximately one-third of a mile long when completed and run between the future East Main and Downtown Bellevue stations under 100th Ave. Sound Transit says it is utilizing the Sequential Excavation Method (SEM) to excavate the tunnel rather than using the cut and cover method or a tunnel boring machine due to the tunnel’s short length and to mitigate community impact. Sound Transit says SEM’s advantages include minimized traffic disruption, reduced noise and dust impacts and the elimination of utility service disruptions.

The tunnel, which was included in the East Link project through the city of Bellevue’s contributions of $100-million, is being constructed 30 to 60 feet below the service, each side will be 16 feet, 3 inches wide with a center dividing wall and crews are expected to excavate three to four feet per day.

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. By the end of 2017, all segments of the East Link extension will be under construction and the entire line will be operational in 2023. The following year Sound Transit will open a 3.7-mile extension further east to new stations in Southeast Redmond and downtown Redmond under funding approved in November 2016.

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