Submersible bridge

[edit] Introduction

A bridge is a spanning structure that creates a passage over an obstacle such as a river, gorge, valley, road, railway and so on. A movable bridge (or moveable bridge) is a spanning structure that can change position (or even shape) to accommodate different situations, such as the requirements of ships, barges and other types of traffic above or below it. Some movable bridges can be inconvenient due to delays caused when one stream of traffic is halted to accommodate the passage of the other.

One type of movable bridge is a submersible or submergible bridge. These structures may also be referred to as ducking bridges. Low water bridges are also sometimes referred to as submersible bridges. However, this is generally an inaccuracy, since low water bridges tend to be fixed structures while submersible bridges are actively movable.

[edit] The purpose of submersible bridges

Submersible bridges are generally built low and close to the average water level. They are generally inexpensive and simple to build and are suited to short spans. They primarily accommodate vehicles and pedestrians.

The construction of modern submersible bridges is similar to that of table bridges (where the roadway is raised upward by a mechanism), but instead of being raised up, the deck of a submersible bridge is pushed down below the surface of the water. The movement of the deck can be controlled by hydraulics.

Submersible bridges are designed and constructed in a manner that supports their operation under conditions such as:

• Flooding. Submersible bridges can be designed to sink below the water level during flooding conditions so floodwaters can move freely over the structure without damaging it. If repairs from flooding are required, they are generally minor.
• Shipping. Submersible bridges are also practical in areas where it is necessary to accommodate waterborne traffic - particularly sailing boats or other tall vessels. Since there is no structure overhead, there is no height restriction for ships passing over the submerged bridge.

[edit] Examples of submersible bridges

Submersible bridges are not common. There is an early example reported in a 1943 article in the magazine, Popular Science. This article explains how the technique was used by an Indian army engineer to allow waterborne vessels to travel over the submerged bridge and through an area where the Tigris and Euphrates rivers meet. Additional evidence of the existence of this bridge is not available.

There are two existing examples of submersible bridges that cross the Corinth Canal in Greece. One is located in Isthmia and the other is in Corinth.

The Japanese Infrastructure Partners (JIP) has been appointed to construct a series of submersible bridges in an area of Myanmar that is susceptible to flooding during the rainy season. Through the Myanmar Submergible Bridge Project, JIP will also provide technical support in an effort to help spread the concept throughout parts of Myanmar where inaccessible roads can be a severe disruption to commerce and every-day life. The first of these concrete bridges, constructed in the southern part of Myanmar, opened on 1 July 2021. It has been named the Moe Nine Bridge.

--Heidi Schwartz

[edit] Related articles on Designing Buildings

• Bridge construction.
• Bridges of the world.
• Bridge structures.
• Flood.
• Movable bridge.
• Navigable aqueduct.
• Pontoon bridge.
• Water engineering.

[edit] External references

• Japan Infrastructure Partners, Myanmar Submergible Bridge Project.