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A view from under two elevated guideways at South Bellevue Station.
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Unique construction methods helped crews complete most of the East Link guideway.

Building bridges to connect light rail to the Eastside

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It’s been a busy year for East Link construction, which recently passed the two-thirds completion milestone.

Anyone who bused, biked, walked or drove anywhere along the 14-mile alignment was able to see the progress in real time, as crews built track and guideway structures between Seattle and Redmond.

None of these projects was more visible than the elevated bridge spanning I-90 in south Bellevue, which loomed over the freeway, seemingly suspended in mid-air for several months.

The overcrossing, constructed using a sophisticated balanced cantilever construction method, took just under a year to complete with movable concrete forms called “travelers.”

Form travelers and other construction equipment can be seen in this image, taken during East Link construction by I-90 in July.
Much of the travelers' work finished over the summer. This shot is from July.

Two travelers moved outward from columns on either side of the freeway, building the 360-foot main span 15.5 feet at a time. The bridge segments met in the middle of I-90, where crews joined them to complete the bridge this fall. 

Here's a video of highlights during the construction process, including a time-lapse of the travelers’ progress:

Just a few months before the I-90 overcrossing was finished, crews completed the bridge across I-405 in downtown Bellevue. In August, the freeway was closed for two weekends so crews could remove the temporary falsework structure that was used during construction.

The 810-foot bridge across I-405 will connect the Bellevue Downtown and Wilburton stations when East Link begins operating in 2023. Crews completed the cast-in-place bridge in just over a year.

Cars drive on southbound I-405, under the new light rail bridge in downtown Bellevue.
Fly above traffic through downtown Bellevue in 2023 on the new light rail bridge.

The I-90 floating bridge also had a big year. Crews added most of the eastbound track, and installed two of the track bridges, as well as the arch-shaped portals for the overhead catenary system. Construction on the floating bridge is expected to wrap up by the end of 2020. 

Other East Link construction progress in 2019 included near-completion of parking garages at the future Redmond Technology and South Bellevue stations, and the Mercer Island station itself. At the Bellevue tunnel, crews constructed the center wall and made significant progress on the final concrete lining. All 10 stations are taking shape.

View from the platform at South Bellevue Station, with the parking garage on the left.
The platform and parking garage at South Bellevue Station are taking shape.

And in just a few more weeks, crews will begin the heavy construction required to connect East Link to the existing light rail line. Recently, they finished a center platform at Pioneer Square station that will be used during the 10-week Connect 2020 period.

Riders should be prepared for changes in their light rail travels starting Jan. 4. It will be a disruptive few weeks, but necessary to get prepared for East Link.

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