bridgetunnel

A bridgetunnel is a type of tunnel that is partially submerged and partially elevated, connecting two landmasses. It typically consists of a bridge section that rises above the water and then transitions into a submerged tunnel section that passes beneath the water. This hybrid design is often employed in locations where a full bridge would be too high or obstructive, or where a full tunnel would be too deep or difficult to construct.

The submerged portion of a bridgetunnel is usually a pre-fabricated tube that is sunk into a trench on the seabed and then covered. The elevated portion is a conventional bridge structure. The transition between the two can be a ramp or a more gradual incline. This design allows for the passage of both surface and subsurface traffic, such as ships and submarines, while also providing a reliable transportation link.

One notable example of a bridgetunnel is the Chesapeake Bay Bridge-Tunnel in Virginia, United States. This structure spans over 17 miles and includes causeways, tunnels, and bridges. It was completed in 1964 and has since served as a vital link for transportation in the region. The bridgetunnel concept offers a flexible solution for crossing waterways, balancing the need for navigation clearance with the practicalities of construction and cost.