Pipeline bridge

A pipeline bridge is a bridge for running a pipeline over a river or another obstacle. Pipeline bridges for liquids and gases are, as a rule, only built when it is not possible to run the pipeline on a conventional bridge or under the river.^{[1][non-primary source needed]} However, as it is more common to run pipelines for centralized heating systems overhead, for this application even small pipeline bridges are common.

A pipeline bridge carrying the Trans-Alaska Pipeline

Pipeline bridges may be made of steel, fiber reinforced polymer, reinforced concrete or similar materials.^[2] They may vary in size and style depending on the size of the pipeline being run. As there is normally a steady flow in pipelines, they can be designed as suspension bridges. They may also be added to an existing bridge.^[1] A pipeline bridge may be equipped with a walkway for maintenance purposes,^[2] but for safety and security reasons, the walkway is usually not open to the public.^{[citation needed]}

One of the world's longest pipeline bridges, built in 1970, is 1,040 meters long and crosses the Fuji River in Shizuoka Prefecture of Japan.^[3] The highest at 393 m is Hegigio Gorge Pipeline Bridge in Papua New Guinea.