Beacon HillUpdate - March 5, 2008: Tunnel boring machine completes second Beacon Hill light rail tunnel
Sound Transit contractors punched through the east side of Beacon Hill completing the second of two 4,300-foot tunnels through the hill for Link light rail trains to begin service in 2009. Obayashi Corporation’s 300-foot-long tunnel boring machine (TBM) nicknamed the “Emerald Mole” emerged within 5 millimeters of its target. Obayashi launched the TBM on its second trip through Beacon Hill in July, 2007 and excavated more than 50,000 cubic yards of soils as it made its way through Beacon Hill. In its path the 100-yard-long machine installed more than 800 pre-cast concrete segments forming the lining of the tunnel. Click here to see video of the break-through >>>
The Beacon Hill tunnel's west portal, or opening, will be under I-5, east of Airport Way. The underground Beacon Hill Station will be located at the southeast corner of Beacon Avenue South and South Lander Street.
The east portal, or opening, will be east of 25th Avenue South and south of South McClellan Street, where the light rail line will emerge to an elevated trackway as it approaches the Mount Baker Station near the intersection of Rainier Avenue South and South Stevens Street.
Obayashi Corporation is the Beacon Hill construction contractor. The contract includes construction of one mile tunnel under Beacon Hill, the west and east portals, a half mile of elevated trackway, and the Beacon Hill and Mount Baker stations.
Obayashi Corporation continues to build the underground Beacon Hill Station. The main shaft (which will ultimately hold the station’s four high-speed elevators) and the secondary shaft (which will provide ventilation and emergency staircases) are both excavated to their final depth. At approximately 165 feet deep, workers have completed major mining activities including the northbound and southbound running tunnels (by use of the tunnel boring machine), all of the station’s cross-passages and ventilation attits, and the underground station concourse, using the sequential excavation technique.
At the Mount Baker Station area, Obayashi is building the elevated trackway between the columns. Most of the elevated trackway sections are in place, and workers are concentrating on the sections on the west side of Martin Luther King Jr. Way South near the earth embankment. Workers continue to pour concrete for the Mount Baker Station’s top, bottom, and sides.
Beacon Hill businesses are open during construction. Learn more from our Marketing Flier (PDF 366kb)
Download Fact Sheets:
Download Forms:
Learn More
Submit Project Feedback
|
Link animations
Construction of the light rail system is underway. Visit our collection of conceptual animations of this exciting new service that begins in 2009.
See it now >>
|
