Beacon Hill tunnel (Seattle)

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Beacon Hill tunnel
Sound Transit Light Link Rail Beacon Hill West Portal.jpg
Tunnel's west portal under an elevated portion of Interstate 5
Overview
Location Seattle, Washington
Coordinates 47°34′37″N 122°19′12″W / 47.577°N 122.320°W / 47.577; -122.320Coordinates: 47°34′37″N 122°19′12″W / 47.577°N 122.320°W / 47.577; -122.320
Status Active
Start SoDo, Seattle, Washington
End Rainier Valley, Seattle, Washington near Mount Baker station
Operation
Constructed 2005–2009
Owner Sound Transit
Traffic Link Light Rail
Technical
Length 1 mi (1.6 km)
Tunnel clearance 21 ft (6.4 m)[1]
Width 21 ft (6.4 m)[1]

Beacon Hill tunnel is a public transit tunnel in Seattle, Washington, carrying the Central Link light rail line under Seattle's Beacon Hill between Rainier Valley and SoDo just east of Interstate 5.[1] The Beacon Hill Link Light Rail station is approximately 165 feet (50 m) underground near the midpoint of the tunnel.

Construction[edit]

Construction of the station began in March 2005 and was completed in July 2009. Obayashi Corporation was the general contractor. The twin running tunnels were excavated with a tunnel boring machine (TBM) built by Mitsubishi, named the "Emerald Mole."[2] The station and crossover tunnels were constructed using the sequential excavation method (SEM), also known as the New Austrian tunnelling method (NATM).[3]

Several workers were injured and one was killed during construction of the tunnel.[4]

The tunnel was completed at a cost of $309 million, versus Obayashi's bid of $280 million.[5]

References[edit]

  1. ^ a b c Beacon Hill Station and Tunnel factsheet (PDF), Sound Transit, 2008 [permanent dead link]
  2. ^ Carl Molesworth (June 5, 2006). "Inside the Emerald Mole". Pacific Builder and Engineer. Archived from the original on 2008-02-14. 
  3. ^ "Sound Transit digs a cutting-edge tunnel". DJC. Retrieved 2009-09-17. 
  4. ^ Levi Pulkkinen; Larry Lange (February 7, 2007), "Worker killed in Sound Transit tunnel: Second accident in three months at light rail site", Seattle Post-Intelligencer 
  5. ^ Eric de Place (October 2009), Sightline Report: Cost Overruns For Seattle-Area Tunnel Projects (PDF), Sightline Institute, retrieved 2013-04-04 [permanent dead link]