Cairo Rail Bridge
Encyclopedia
Cairo Rail Bridge is the name of two bridges crossing the Ohio River
Ohio River
The Ohio River is the largest tributary, by volume, of the Mississippi River. At the confluence, the Ohio is even bigger than the Mississippi and, thus, is hydrologically the main stream of the whole river system, including the Allegheny River further upstream...

 near Cairo, Illinois
Cairo, Illinois
Cairo is the southernmost city in the U.S. state of Illinois. It is the county seat of Alexander County. Cairo is located at the confluence of the Mississippi and Ohio rivers. The rivers converge at Fort Defiance State Park, an American Civil War fort that was commanded by General Ulysses S. Grant...

. The original was an 1889 George S. Morison through truss and deck truss bridge replaced by the current bridge in 1952. The second and current bridge is a through truss bridge that reused many of the original bridge piers. As of 2007, trains like the City of New Orleans
City of New Orleans
The City of New Orleans is a nightly passenger train operated by Amtrak which travels between Chicago, Illinois and New Orleans, Louisiana. Before Amtrak's formation in 1971, the train was operated by the Illinois Central Railroad along the same route . The train currently operates on a 19½ hour...

 travel over the Ohio River supported by the same piers whose construction began in 1887.

Original bridge

On July 1, 1887 construction began on the first caisson
Caisson (engineering)
In geotechnical engineering, a caisson is a retaining, watertight structure used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair of ships. These are constructed such that the water can be pumped out, keeping the working...

 for the foundations of the bridge piers. The first caisson descended into the riverbed at a rate of around 4 inches (10.2 cm) per day. Two men died and several more were seriously injured sealing the first caisson at a depth of 77 feet (23.5 m). Despite increased precautions following the deaths, a total of five men died of decompression sickness
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...

 during construction. February 19, 1889 the last pier was completed. The first train crossed the bridge from Illinois to Kentucky on October 29, 1889. Work continued until it was turned over to the railroad on March 1, 1890. Total cost of the structure exceeded $2.6 million, with nearly $1.2 million for the substructure alone. In order to comply with regulations meant to allow steam boat travel on the Ohio, the bridge was required to be 53 feet (16.2 m) above the river's high water mark. This resulted in the structure extending nearly 250 feet (76.2 m) from the bottom of the deepest foundation to the top of the highest iron work. The bridge, substructure and super structure weighed 194.6 million pounds (88,270 t), excluding the approaches.

On October 31, 1895 a 6.6 earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

 on the New Madrid Seismic Zone
New Madrid Seismic Zone
The New Madrid Seismic Zone , sometimes called the New Madrid Fault Line, is a major seismic zone and a prolific source of intraplate earthquakes in the southern and midwestern United States, stretching to the southwest from New Madrid, Missouri.The New Madrid fault system was responsible for the...

  with an epicenter at Charleston, Missouri
Charleston, Missouri
Charleston is a city in Mississippi County, Missouri, United States. The population was 4,732 at the 2000 census. It is the county seat of Mississippi County and it is a home to a local correctional facility.-History:...

 cracked a pier on the bridge. The quake is the biggest quake since the 1812 New Madrid earthquake which at 8.3 was the biggest recorded quake in the contiguous United States
Contiguous United States
The contiguous United States are the 48 U.S. states on the continent of North America that are south of Canada and north of Mexico, plus the District of Columbia....

.

Cairo bridge's two 518.5 ft (158 m) main spans were the longest pin-connected Whipple
Squire Whipple
Squire Whipple C.E. was a civil engineer born in Hardwick, Massachusetts, USA. His family moved to New York when he was thirteen. He studied at Fairfield Academy. He graduated from Union College after only one year...

 truss spans ever built. Pier IX, the largest, alone weighed 11000 short tons (9,821.4 LT). At the time, the bridge was the largest and most expensive ever undertaken in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. At 10580 feet (3,224.8 m), it was the longest metallic structure in the world. Its total length was 20461 ft (6,236.5 m) including wooden approach trestles. Its construction completed the first rail link between Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...

 and New Orleans and revolutionized north-south rail travel along 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...

.

External links

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