Frisco Bridge
Encyclopedia
The Frisco Bridge, previously known as the Memphis Bridge, is a cantilevered
Cantilever bridge
A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from...

 through truss bridge
Truss bridge
A truss bridge is a bridge composed of connected elements which may be stressed from tension, compression, or sometimes both in response to dynamic loads. Truss bridges are one of the oldest types of modern bridges...

 carrying a rail line across the Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

 between West Memphis, Arkansas
West Memphis, Arkansas
West Memphis is the largest city in Crittenden County, Arkansas, United States. The population was 27,666 at the 2000 census, with an estimated population of 28,181 in 2005, and 31,329 in 2011 ranking it as the state's 11th largest city, behind Hot Springs...

 and Memphis, Tennessee
Memphis, Tennessee
Memphis is a city in the southwestern corner of the U.S. state of Tennessee, and the county seat of Shelby County. The city is located on the 4th Chickasaw Bluff, south of the confluence of the Wolf and Mississippi rivers....

.

Construction

At the time of the Memphis bridge construction, it was a significant technological challenge and is considered to be chief engineer George S. Morison's crowning achievement. No other bridges had ever been attempted on the Lower Mississippi River
Lower Mississippi River
The Lower Mississippi River is the portion of the Mississippi River downstream of Cairo, Illinois. From the confluence of the Ohio River and Upper Mississippi River at Cairo, the Lower flows just under 1600 kilometers to the Gulf of Mexico...

.

The bridge is built entirely of open-hearth steel, a newly developed material at the time of construction. The structure features a 790 foot main span and two additional 600 foot spans. Its 65 foot height above the water was the highest clearance of any U.S. bridge of that era. The construction of the piers went nearly 100 feet below the water's surface.

Though some sources claim two cantilevered roadways were added to the bridge in the 1930s, one on each side, they probably confuse this bridge with the neighboring Harahan Bridge
Harahan Bridge
The Harahan Bridge is a cantilevered through truss bridge carrying two rail lines across the Mississippi River between West Memphis, Arkansas and Memphis, Tennessee. The consulting engineer in charge was Ralph Modjeski. The bridge also carried motor vehicles from 1917–1949, when the Memphis &...

, which had two cantilevered roadways from 1917 until the Memphis & Arkansas Bridge opened in 1949. Today, the Harahan Bridge still has the metal remains of its cantilevered roadways; the Frisco Bridge does not. However, pedestrians, buggies, and some automobiles used the main deck of the Frisco Bridge before the Harahan Bridge opened (the bridge was closed to such traffic while a train was crossing).

Construction for the Kansas City, Fort Scott and Memphis Railroad began in 1888 and was completed May 12, 1892. In the end the project created a bridge that was the farthest south on the Mississippi River, featured the longest span in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and cost nearly 3 million dollars.

A testament to its design and construction, as of 2009 the bridge is still used by BNSF Railway
BNSF Railway
The BNSF Railway is a wholly owned subsidiary of Berkshire Hathaway Inc., and is headquartered in Fort Worth, Texas. It is one of seven North American Class I railroads and the second largest freight railroad network in North America, second only to the Union Pacific Railroad, its primary...

. The bridge is listed as a Historic Civil Engineering Landmark.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK