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]
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The Port Authority of Allegheny County (Pittsburgh, Pennsylvania) has a major transit improvement project dubbed the North Shore Connector. Its main components are twin bored tunnels 1.2 miles long that will connect the Port Authority’s Light Rail Transit system, the T, 1.2 miles from the Gateway Subway Station underneath Stanwix Street and the Allegheny River to the North Shore. It will travel under the river and provide three new stations and allow for future improvements beneficial to future development and continued downtown revitalization. The $435 million project is making news recently for cost increases, drawing comparisons to Boston’s Big Dig much to the dismay of the Port Authority. Read on for project maps, links and more info.