The tunnel liner that is being placed by the Bertha tunnel boring machine consists of precast concrete segments. This video by the WSDOT shows how they are made at the casting yard, and what Bertha does with them once they get delivered to her where the action is happening. The finished tunnel will consist of over 14,000 of these precast segments! [Source: WSDOT YouTube Channel. Image: YouTube]
The world’s largest Tunnel Boring Machine or TBM just arrived in Seattle last week from Japan. Hitachi Zosen Corp built the 57 foot diameter TBM and tested it before disassembling it for the journey by […]
Seattle Tunnel Partners released a new schedule this week for the repair of the damaged seals on the Bertha Tunnel Boring Machine. This revised schedule shows that the TBM won’t be digging again until March […]
In Washington D.C., the D.C. Water and Sewer Authority (D.C. WASA) finalized a lont-term plan in 2002 aimed at reducing combined sewer outfalls into the Potomac River and its tributary, the Anacostia River. A major portion of this plan is a $2.2 Billion (US) deep tunnel program to handle excess stormwater flows and prevent the combined sewage from being discharged into the environment. Read on for a map and more info. (Photo of Anacostia River, by D.C. WASA)
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