The first long underwater tunnel in the world designed for motor vehicle use was built from 1920 to 1927. The 29.5-foot-diameter, 8,500-foot-long twin tubes of this tunnel were shield-driven by the pneumatic method through extremely difficult river-bottom conditions that were overcome by the ingenuity and determination of its engineers, Clifford M. Holland, Milton H. Freeman, and Ole Singstad. They were the largest in the United States when built.
Iron-lined
YearAdded:
Image Credit: Courtesy Flickr/Bill Benzon (CC BY-SA 2.0)Era_date_from: 1920
1984
Innovations
The first long underwater tunnel in the world designed for motor vehicle use was built from 1920 to 1927. The 29.5-foot-diameter, 8,500-foot-long twin tubes of this tunnel were shield-driven by the pneumatic method through extremely difficult river-bottom conditions that were overcome by the… Read More