Guy F Atkinson Construction has been named as the low bidder on Sound Transit’s 2,150ft (655m) light rail SEM tunnel in downtown Bellevue, Washington, as part of Sound Transit’s East Link Extension project.
Atkinson’s price of $121.4 million was the lowest of seven bids, and was more than 20% below the engineer’s estimate of $156.9 million.
The contract includes site work, demolition of several structures, and the tunnel. The tunnel will be constructed by the sequential excavation method (SEM), with about 250ft at the south portal built within a cut-and-cover box structure.
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The south portal will be near 110th Avenue Southeast and East Main Street. The tunnel will run under 110th Avenue Northeast for about half a mile before turning east near Northeast Sixth Street. The north portal will be at Northeast Sixth Street, near Bellevue City Hall.
HJH Final Design Partners is the designer for the tunnel and downtown station. The team includes Hatch Mott MacDonald, Jacobs Engineering Group and HNTB.
The second lowest bid, $143 million, was from Downtown Tunnel Partners. Other bidders were: Bellevue Tunnel JV, Dragados, Frontier-Kemper, Kiewit and Salini Impregilo Healy JV.
Construction on the tunnel could begin next spring with completion expected in spring 2020. It will be part of the $3.6 billion East Link line, which is expected to open in 2023.
The 14-mile East Link route will run from downtown Seattle to Mercer Island and Bellevue, and then to the Overlake area in Redmond. It will have 10 stations, The trip between downtown Seattle and downtown Bellevue should be 22 minutes.