Bridge

A bridge is a structure built to span physical obstacles without closing the way underneath such as a body of water, valley, or road, for the purpose of providing passage over the obstacle. There are many different designs that each serve a particular purpose and apply to different situations. Designs of bridges vary depending on the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it.

Etymology

The Oxford English Dictionary traces the origin of the word bridge to an Old English word brycg, of the same meaning. The word can be traced directly back to Proto-Indo-European *bʰrēw-. The word for the card game of the same name has a different origin.

History

The first bridges made by humans were probably spans of cut wooden logs or planks and eventually stones, using a simple support and crossbeam arrangement. Some early Americans used trees or bamboo poles to cross small caverns or wells to get from one place to another. A common form of lashing sticks, logs, and deciduous branches together involved the use of long reeds or other harvested fibers woven together to form a connective rope capable of binding and holding together the materials used in early bridges.

Dubuque Rail Bridge

The Dubuque Rail Bridge carries a single rail line across the Mississippi River between Dubuque, Iowa, and East Dubuque, Illinois, near river mile 580.

It is currently operated by Canadian National Railway. as a result of their 1999 purchase of Illinois Central Railroad.

History

The original swing bridge was constructed by Andrew Carnegie and operated by the Dunleith & Dubuque Bridge Company opening in December 1868, primarily used by the Illinois Central Railroad.

The Dubuque Rail Bridge was rebuilt in the 1890s and has 5 spans and a swing-span. Because of a 150-foot bluff very close to the Mississippi riverbank on the Illinois side, the railroad tracks enter a 1/4-mile tunnel that curves 90-degrees to the south to allow trains to proceed along the tracks adjacent to the river south of the bridge.

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