Ballard Siphon replacement tunnel - TunnelCast
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31 October, 2013: Construction work to replace wood-stave wastewater siphons built in 1935 under the Lake Washington ship canal in Seattle, Washington, is entering its final phases with the final 84in (2m) diameter fiberglass reinforced liner pipe being installed into the completed 2,000ft (610m) long x 2.6m diameter tunnel excavated by an EPBM at about 18m beneath the bed of Salmon Bay. Application of innovative shaft sinking technology is one of the highlights on the successful job as explained by Marty Noble, Project Representative for owner King County, and Rich Mascarello, Project Manager for contractor JW Fowler. The new CSO wastewater tunnel is on schedule to begin operation in early 2014.

References
Seattle mobilizes for sewer upgrade - TunnelTalk, Sept 2011
US debut for vertical shaft machine technology - TunnelTalk, April 2012

Snapshot

Ballard Siphon replacement project

Sterling Noren reporting for TunnelCast
Location:
Salmon Bay, Seattle, Washington
Dimensions:
2,000ft long (610m) up to 120ft (37m) beneath the Lake Washington ship canal
Type:
CSO wastewater tunnel to replace a pair of wood-stave siphons, built in 1935
Owner:
King County Department of Natural Resources and Parks Wastewater Treatment Division
Project Value:
$38 million
Contract Value:
$32.7 million
Launch shaft:
145ft deep x 30ft diameter (44m x 9m)
Reception shaft:
100ft deep x 70ft diameter (30.5m x 21m)
Methods:
2.6m diameter Herrenknecht EBPM
Herrenknecht VSM (vertical shaft machine)
Contractor:
JW Fowler Company of Oregon
Designer:
TetraTech & Staheli
Construction Management:
Jacobs Associates