Eads Bridge
Encyclopedia
The Eads Bridge is a combined road and railway bridge over the Mississippi River
at St. Louis
, connecting St. Louis and East St. Louis, Illinois
.
The bridge is named for its designer and builder, James B. Eads. When completed in 1874, the Eads Bridge was the longest arch bridge in the world, with an overall length of 6,442 feet (1,964 m). The ribbed steel arch spans were considered daring, as was the use of steel as a primary structural material: it was the first such use of true steel in a major bridge project.
The Eads Bridge was also the first bridge to be built using cantilever
support methods exclusively, and one of the first to make use of pneumatic caissons
. The Eads Bridge caissons, still among the deepest ever sunk, were responsible for one of the first major outbreaks of "caisson disease
" (also known as "the bends" or decompression sickness
). Fifteen workers died, two other workers were permanently disabled, and 77 were severely afflicted.
On 14 June 1874, John Robinson led a "test elephant
" on a stroll across the new Eads Bridge to prove it was safe. A big crowd cheered as the elephant from a traveling circus lumbered towards Illinois. It was believed that elephants had instincts that would keep them from setting foot on unsafe structures. Two weeks later, Eads sent 14 locomotive
s back and forth across the bridge at one time.
The Eads Bridge, which became an iconic image of the city of St. Louis, from the time of its erection until 1965 when the Gateway Arch was constructed, is still in use. The bridge crosses the St. Louis riverfront between Laclede's Landing
, to the north, and the grounds of the Gateway Arch
, to the south. Today the road deck has been restored, allowing vehicular and pedestrian traffic to cross the river. The St. Louis MetroLink
light rail line has used the rail deck since 1993.
The Eads Bridge was built by the Illinois and St. Louis Bridge Company, with the Keystone Bridge Company serving as subcontractor for superstructure erection.
The domination of the river trade was no longer as important as before the American Civil War
, and Chicago was fast gaining as the center of commerce in the West. The Bridge was conceived as a solution to reverse this new found eminence.
Meanwhile in an attempt to secure their future, steamboat interests successfully lobbied to place restrictions on bridge construction, requiring spans and heights previously unheard of. Ostensibly this would maintain sufficient operating room for steamboats for the then foreseeable future beneath the bridge’s base. Their unproclaimed purpose was to require a bridge so grand and lofty that it would be impossible to erect according to conventional building techniques. The desired consequence would be the prevention of any structure, and continued sole dependence on river traffic to sustain commerce in the region.
A bridge of this magnitude would require a radical design solution.
Though the ribbed arch had been a known construction technique for centuries. The triple span, tubular metallic arch construction was supported by two shore abutments and two mid-river piers. Four pairs of arches per span (upper and lower) were set eight feet apart, supporting an upper deck for vehicular traffic and a lower deck for rail traffic.
Construction involved varied and confusing design elements and pressures. State and federal charters precluded suspension
or draw bridges, or wood construction. There were also constraints on span size and regarding the height above the water line. The location dictated a change from the low Illinois floodplain of the east bank to the high Missouri cliff on the west bank of the river. The bedrock was extremely deep, 38 m below water level on the Illinois side and 26 m below on the Missouri side.
These pressures resulted in a bridge noted as innovative for precision and accuracy of construction and quality control. Utilization of cast chromium steel components is arguably the first use of structural alloy steel in a major building construction. (Though the bridge as actually completed contained large—and unknown—amounts of wrought iron.) Eads argued that the great compressive strength of steel was ideal for use in the upright arch design. This decision resulted from a curious combination of chance and necessity, due to the insufficient strength of alternative material choices.
The particular physical difficulties of the site stimulated interesting solutions to construction problems. The deep caissons used for pier and abutment construction signaled a new chapter in civil engineering
. Unable to construct falsework
to erect the arches because they would obstruct river traffic, Eads's engineers devised a cantilevered rigging system to close the arches.
Although recognized as an innovative and exciting achievement, the Eads Bridge was undercapitalized
during construction and burdened with debt. With its focus on the river, St. Louis had a lack of adequate rail terminal facilities, and the bridge was poorly planned to coordinate rail access. An engineering and aesthetic success, the bridge was bankrupt within a year of opening.
Granite for the bridge came from the Iron County, Missouri
quarry of Missouri Governor and U.S. Senator B. Gratz Brown
who had helped secure federal financing for the bridge.
The Merchants Exchange eventually lost ownership to the Terminal Railroad Association of St. Louis
. The Exchange, fearing a Terminal Railroad rail monopoly
on the bridges, would then build the Merchants Bridge
(which in turn would eventually be taken over by the Terminal Railroad. The Terminal Railroad transferred the bridge to the City of St. Louis in 1989 in exchange for the MacArthur Bridge
.
Eads Bridge had long hosted only passenger trains on its rail deck. By the 1970s the TRRA had abandoned its Eads trackage, as the bridge had lost all remaining passenger rail traffic to the MacArthur during the early years of Amtrak
; the dimensions of modern passenger diesels were incompatible with both the bridge and the adjoining tunnel linking the Union Station trackage with Eads.
In 1998, the Naval Facilities Engineering Service Center
investigated the effects of the April 4, 1998, ramming of the bridge by the barge Anne Holly. The ramming resulted in the near breakaway of the SS Admiral riverboat casino
; several recommended changes reduced the odds of this happening in the future.
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...
at St. Louis
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...
, connecting St. Louis and East St. Louis, Illinois
East St. Louis, Illinois
East St. Louis is a city located in St. Clair County, Illinois, USA, directly across the Mississippi River from St. Louis, Missouri in the Metro-East region of Southern Illinois. As of the 2010 census, the city had a total population of 27,006, less than one-third of its peak of 82,366 in 1950...
.
The bridge is named for its designer and builder, James B. Eads. When completed in 1874, the Eads Bridge was the longest arch bridge in the world, with an overall length of 6,442 feet (1,964 m). The ribbed steel arch spans were considered daring, as was the use of steel as a primary structural material: it was the first such use of true steel in a major bridge project.
The Eads Bridge was also the first bridge to be built using cantilever
Cantilever
A cantilever is a beam anchored at only one end. The beam carries the load to the support where it is resisted by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trusses or slabs.This is in...
support methods exclusively, and one of the first to make use of pneumatic caissons
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...
. The Eads Bridge caissons, still among the deepest ever sunk, were responsible for one of the first major outbreaks of "caisson disease
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
" (also known as "the bends" or decompression sickness
Decompression sickness
Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
). Fifteen workers died, two other workers were permanently disabled, and 77 were severely afflicted.
On 14 June 1874, John Robinson led a "test elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
" on a stroll across the new Eads Bridge to prove it was safe. A big crowd cheered as the elephant from a traveling circus lumbered towards Illinois. It was believed that elephants had instincts that would keep them from setting foot on unsafe structures. Two weeks later, Eads sent 14 locomotive
Locomotive
A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...
s back and forth across the bridge at one time.
The Eads Bridge, which became an iconic image of the city of St. Louis, from the time of its erection until 1965 when the Gateway Arch was constructed, is still in use. The bridge crosses the St. Louis riverfront between Laclede's Landing
Laclede's Landing
Laclède's Landing is a popular attraction located in St. Louis, Missouri, United States.Located just north of the Eads Bridge on the Mississippi Riverfront, the Landing is a multi-block collection of cobblestone streets and vintage brick-and-cast-iron warehouses dating from 1850 through 1900, now...
, to the north, and the grounds of the Gateway Arch
Jefferson National Expansion Memorial
The Jefferson National Expansion Memorial is in St. Louis, Missouri, near the starting point of the Lewis and Clark Expedition. It was designated as a National Memorial by Executive Order 7523, on December 21, 1935, and is maintained by the National Park Service .The park was established to...
, to the south. Today the road deck has been restored, allowing vehicular and pedestrian traffic to cross the river. The St. Louis MetroLink
St. Louis Metrolink
MetroLink is the light rail transit system in the Greater St. Louis area of Missouri and the Metro East area of Illinois. The entire system currently consists of two lines connecting Lambert-St. Louis International Airport and Shrewsbury, MO with Scott Air Force Base near Shiloh, Illinois through...
light rail line has used the rail deck since 1993.
History
The domination of the river trade was no longer as important as before the American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...
, and Chicago was fast gaining as the center of commerce in the West. The Bridge was conceived as a solution to reverse this new found eminence.
Meanwhile in an attempt to secure their future, steamboat interests successfully lobbied to place restrictions on bridge construction, requiring spans and heights previously unheard of. Ostensibly this would maintain sufficient operating room for steamboats for the then foreseeable future beneath the bridge’s base. Their unproclaimed purpose was to require a bridge so grand and lofty that it would be impossible to erect according to conventional building techniques. The desired consequence would be the prevention of any structure, and continued sole dependence on river traffic to sustain commerce in the region.
A bridge of this magnitude would require a radical design solution.
Though the ribbed arch had been a known construction technique for centuries. The triple span, tubular metallic arch construction was supported by two shore abutments and two mid-river piers. Four pairs of arches per span (upper and lower) were set eight feet apart, supporting an upper deck for vehicular traffic and a lower deck for rail traffic.
Construction involved varied and confusing design elements and pressures. State and federal charters precluded suspension
Suspension bridge
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century...
or draw bridges, or wood construction. There were also constraints on span size and regarding the height above the water line. The location dictated a change from the low Illinois floodplain of the east bank to the high Missouri cliff on the west bank of the river. The bedrock was extremely deep, 38 m below water level on the Illinois side and 26 m below on the Missouri side.
These pressures resulted in a bridge noted as innovative for precision and accuracy of construction and quality control. Utilization of cast chromium steel components is arguably the first use of structural alloy steel in a major building construction. (Though the bridge as actually completed contained large—and unknown—amounts of wrought iron.) Eads argued that the great compressive strength of steel was ideal for use in the upright arch design. This decision resulted from a curious combination of chance and necessity, due to the insufficient strength of alternative material choices.
The particular physical difficulties of the site stimulated interesting solutions to construction problems. The deep caissons used for pier and abutment construction signaled a new chapter in civil engineering
Civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...
. Unable to construct falsework
Falsework
Falsework consists of temporary structures used in construction to support spanning or arched structures in order to hold the component in place until its construction is sufficiently advanced to support itself...
to erect the arches because they would obstruct river traffic, Eads's engineers devised a cantilevered rigging system to close the arches.
Although recognized as an innovative and exciting achievement, the Eads Bridge was undercapitalized
Capital (economics)
In economics, capital, capital goods, or real capital refers to already-produced durable goods used in production of goods or services. The capital goods are not significantly consumed, though they may depreciate in the production process...
during construction and burdened with debt. With its focus on the river, St. Louis had a lack of adequate rail terminal facilities, and the bridge was poorly planned to coordinate rail access. An engineering and aesthetic success, the bridge was bankrupt within a year of opening.
Granite for the bridge came from the Iron County, Missouri
Iron County, Missouri
Iron County is a county located in the Lead Belt region in Southeast Missouri in the United States. As of the 2000 U.S. Census, the county's population was 10,697. A 2008 estimate, however, showed the population to be 9,918. The largest city and county seat is Ironton...
quarry of Missouri Governor and U.S. Senator B. Gratz Brown
B. Gratz Brown
Benjamin Gratz Brown was an American politician. He was a Senator, the 20th Governor of Missouri, and the Liberal Republican and Democratic Party Vice presidential candidate in the presidential election of 1872.-Early life:...
who had helped secure federal financing for the bridge.
The Merchants Exchange eventually lost ownership to the Terminal Railroad Association of St. Louis
Terminal Railroad Association of St. Louis
The Terminal Railroad Association of St. Louis is a terminal railroad owned by railroads in St. Louis, Missouri which handles traffic through its metropolitan area.-Components:It was founded in 1889 in a deal orchestrated by Jay Gould by:...
. The Exchange, fearing a Terminal Railroad rail monopoly
Monopoly
A monopoly exists when a specific person or enterprise is the only supplier of a particular commodity...
on the bridges, would then build the Merchants Bridge
Merchants Bridge
The Merchants Bridge is a rail bridge crossing the Mississippi River in St. Louis, Missouri owned by the Terminal Railroad Association of St. Louis. It opened in May 1889 and crossed the river three miles north of the Eads Bridge....
(which in turn would eventually be taken over by the Terminal Railroad. The Terminal Railroad transferred the bridge to the City of St. Louis in 1989 in exchange for the MacArthur Bridge
MacArthur Bridge (St. Louis)
The MacArthur Bridge over the Mississippi River between St. Louis, Missouri and East St. Louis, Illinois is a 647 foot long truss bridge. Construction on the bridge was begun in 1909 by the city of St. Louis to break the Terminal Railroad Association of St. Louis's monopoly on the area's railroad...
.
Eads Bridge had long hosted only passenger trains on its rail deck. By the 1970s the TRRA had abandoned its Eads trackage, as the bridge had lost all remaining passenger rail traffic to the MacArthur during the early years of Amtrak
Amtrak
The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...
; the dimensions of modern passenger diesels were incompatible with both the bridge and the adjoining tunnel linking the Union Station trackage with Eads.
In 1998, the Naval Facilities Engineering Service Center
NFESC
NFESC, the Naval Facilities Engineering Service Center provides engineering services, technology testing, specialized facilities, and expertise in these facilities...
investigated the effects of the April 4, 1998, ramming of the bridge by the barge Anne Holly. The ramming resulted in the near breakaway of the SS Admiral riverboat casino
Riverboat casino
A riverboat casino is a type of casino found in several areas of the United States which use a riverboat as a casino. Several states authorized this type of casino to limit the areas where casinos could be constructed under a type of legal fiction.-History:...
; several recommended changes reduced the odds of this happening in the future.
External links
- National Historic Landmark Designation - Statement of Significance
- Eads Bridge - the History and Heritage of Civil Engineering webpage (American Society of Civil Engineers)
- Bridge Pros: Eads Bridge
- Bridge info at Historic Bridges of the United States.
- maps.google.com zoomed in, hybrid mode
- High resolution panoramic image of an Eads Bridge span
- Library of Congress HAER record