Segmental bridge
Encyclopedia
As its name implies, a segmental bridge is a bridge
built in short sections (called segments), i.e., one piece at a time, as opposed to traditional methods that build a bridge in very large sections. The bridge is made of concrete
that is either cast-in-place (constructed fully in its final location) or precast concrete
(built at another location and then transported to their final location for placement in the full structure).
These bridges are very economical for long spans (over 100 meters), especially when access to the construction site is restricted. They are also chosen for their aesthetic appeal.
The first precast segmental concrete bridge, built in 1962, crossed the Seine River in France
.
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
built in short sections (called segments), i.e., one piece at a time, as opposed to traditional methods that build a bridge in very large sections. The bridge is made of concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
that is either cast-in-place (constructed fully in its final location) or precast concrete
Precast concrete
By producing precast concrete in a controlled environment , the precast concrete is afforded the opportunity to properly cure and be closely monitored by plant employees. Utilizing a Precast Concrete system offers many potential advantages over site casting of concrete...
(built at another location and then transported to their final location for placement in the full structure).
These bridges are very economical for long spans (over 100 meters), especially when access to the construction site is restricted. They are also chosen for their aesthetic appeal.
History
The first segmental concrete bridge, built in 1950, was cast-in-place across the Lahn River in Balduinstein, Germany.The first precast segmental concrete bridge, built in 1962, crossed the Seine River in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
.
Construction
The sequence of construction is similar to traditional concrete bridge building, i.e., build the support towers (columns), build the temporary falsework, build the deck, perform finish work. The principal differences are as follows:- The support towers may be built segmentally. Often this is accomplished using "slip-form" construction, where the falsework moves (slips) upward following sequential concrete "pours." The falsework uses the newly constructed concrete as the basis for moving upward.
- After the towers are built, a superstructure is built atop the towers. This superstructure serves as the "launching" point for building the deck. (The deck is often built in both directions away from the tower, simultaneously.)
- The deck is now constructed sequentially, beginning at the tower, one section at a time.
- In cast-in-place bridges, the falsework is connected to the previously installed concrete and allowed to cantilever freely. Next, the permanent reinforcing steel and supports are installed. Finally, the concrete is placed and cured, freeing the falsework to be moved.
- In pre-cast bridges, the concrete segment is constructed on the ground, and then transported and hoisted into place. As the new segment is suspended in place by the crane, workers install steel reinforcing that attaches the new segment to preceding segments. Each segment of the bridge designed to accept connections from both preceding and succeeding segments.
- The process in step 3 is repeated until the span is completed.
Notable examples
- Chesapeake and Delaware Canal Bridge in DelawareDelawareDelaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...
is a cable-stayed bridgeCable-stayed bridgeA cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....
using precast concrete segments for the approach and center spans - Vancouver SkyTrain's Millennium LineMillennium LineThe Millennium Line is the second rapid transit line built in the SkyTrain light metro rapid transit system in Metro Vancouver, British Columbia, Canada. The line is owned and operated by TransLink. Millennium Line uses the colour yellow on route maps, wayfinding and station signage.-History:When...
as well as the elevated portion of the Canada LineCanada LineCanada Line is a rapid transit line in the Metro Vancouver region of British Columbia, Canada. Opened in August 2009, it is the third line in TransLink's SkyTrain metro network, servicing Vancouver, Richmond, and the Vancouver International Airport...
. - Linn Cove ViaductLinn Cove ViaductLinn Cove Viaduct is a 1243-foot concrete segmental bridge which snakes around the slopes of Grandfather Mountain in North Carolina. It was completed in 1983 at a cost of $10 million and was the last section of the Blue Ridge Parkway to be finished...
in the Blue Ridge MountainsBlue Ridge MountainsThe Blue Ridge Mountains are a physiographic province of the larger Appalachian Mountains range. This province consists of northern and southern physiographic regions, which divide near the Roanoke River gap. The mountain range is located in the eastern United States, starting at its southern-most...
, North CarolinaNorth CarolinaNorth Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
(precast) - Manwel Dimech Bridge in St. Julian'sSt. Julian'sSt Julian's is a town in Malta situated along the coast, north of the country's capital, Valletta. It is known for tourism-oriented businesses, such as hotels, restaurants and nightclubs, centred mostly in an area known as Paceville.-General:...
(San Ġiljan), MaltaMaltaMalta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...
. This bridge connects the two parts of Regional Road and pass over Għomar Valley. - Seven Mile BridgeSeven Mile BridgeThe Seven Mile Bridge is a famous bridge in the Florida Keys, in Monroe County, Florida, United States. It connects Knight's Key in the Middle Keys to Little Duck Key in the Lower Keys...
in the FloridaFloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
KeysFlorida KeysThe Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...
(precast) - The Interstate H-3Interstate H-3Interstate H-3 is an intrastate Interstate Highway located on the island of O'ahu in the state of Hawai'i in the United States. H-3 is also known as the John A. Burns Freeway...
viaducts through the Ko'olau MountainsKoolau RangeKoolau Range is a name given to the fragmented remnant of the eastern or windward shield volcano of the Hawaiian island of Oahu. It is not a mountain range in the normal sense, because it was formed as a single mountain called Koolau Volcano...
, OahuOahuOahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...
, HawaiiHawaiiHawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
(CIP Segmental) - The new Pennsylvania TurnpikePennsylvania TurnpikeThe Pennsylvania Turnpike is a toll highway system operated by the Pennsylvania Turnpike Commission in the Commonwealth of Pennsylvania, United States. The three sections of the turnpike system total . The main section extends from Ohio to New Jersey and is long...
(I-76Interstate 76 (east)Interstate 76 is an Interstate Highway in the United States, running 435 miles from an interchange with Interstate 71 west of Akron, Ohio, east to Interstate 295 near Camden, New Jersey....
) bridges over the Susquehanna RiverSusquehanna RiverThe Susquehanna River is a river located in the northeastern United States. At long, it is the longest river on the American east coast that drains into the Atlantic Ocean, and with its watershed it is the 16th largest river in the United States, and the longest river in the continental United...
south of Harrisburg, PennsylvaniaHarrisburg, PennsylvaniaHarrisburg is the capital of Pennsylvania. As of the 2010 census, the city had a population of 49,528, making it the ninth largest city in Pennsylvania...
(precast) - The Eastern span replacement of the San Francisco-Oakland Bay BridgeEastern span replacement of the San Francisco-Oakland Bay BridgeThe eastern span replacement of the San Francisco – Oakland Bay Bridge has been under construction since 2002. Originally scheduled to open in 2007, it is now scheduled to open to traffic in 2013 at an estimated cost of $6.3 billion....
viaduct (precast) - The Benicia-Martinez BridgeBenicia-Martinez BridgeThe Benicia–Martinez Bridge refers to three parallel bridges which cross the Carquinez Strait just west of Suisun Bay; the spans link Benicia, California to the north with Martinez, California to the south...
(northbound span) between BeniciaBenicia, CaliforniaBenicia is a waterside city in Solano County, California, United States. It was the first city in California to be founded by Anglo-Americans, and served as the state capital for nearly thirteen months from 1853 to 1854. The population was 26,997 at the 2010 census. The city is located in the San...
and MartinezMartinez, CaliforniaMartinez is a city and the county seat of Contra Costa County, California, United States. The population was 35,824 at the 2010 census. The downtown is notable for its large number of preserved old buildings...
, CACaliforniaCalifornia is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
(CIP Segmental) - The Four Bears BridgeFour Bears BridgeFour Bears Bridge is one of two bridges built over the Missouri River on the Fort Berthold Reservation in the U.S. state of North Dakota. The current bridge which opened in 2005 is the second largest bridge in the state and replaces an earlier bridge built in 1955...
over the Missouri RiverMissouri RiverThe Missouri River flows through the central United States, and is a tributary of the Mississippi River. It is the longest river in North America and drains the third largest area, though only the thirteenth largest by discharge. The Missouri's watershed encompasses most of the American Great...
in North DakotaNorth DakotaNorth Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
utilizes precast concrete segments, erected with the balanced cantilever method (precast) - The High Five InterchangeHigh Five Interchangethumb|High Five interchange.The High Five Interchange is a five-level freeway interchange, designed by the HNTB Corporation, that connects Lyndon B. Johnson Freeway and Central Expressway in Dallas, Texas, United States...
connecting US-75U.S. Route 75 in TexasIn the U.S. state of Texas, U.S. Highway 75 is a U.S. Highway that begins in Dallas and heads north to the Oklahoma border.-History:In the initial assignment of state highways in 1917, Dallas-Fort Worth and Houston were connected by a branch of State Highway 2 , which ran via Waco and Bryan and...
and I-635Interstate 635 (Texas)Interstate 635 or the Lyndon B. Johnson Freeway is a partial loop around Dallas, Texas between Interstate 20 in Balch Springs, Texas and State Highway 121 at the north entrance of the Dallas-Fort Worth International Airport in Grapevine, Texas. The route is long...
in Dallas, TXTexasTexas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
(precast) - The AirTrainAirTrain JFKAirTrain JFK is a 3-line, -long people mover system and elevated railway in New York City providing service to John F. Kennedy International Airport...
linking NY's John F. Kennedy International AirportJohn F. Kennedy International AirportJohn F. Kennedy International Airport is an international airport located in the borough of Queens in New York City, about southeast of Lower Manhattan. It is the busiest international air passenger gateway to the United States, handling more international traffic than any other airport in North...
with the Jamaica Transit Center - The ramps leading between the Brooklyn Queens Expressway (NY I-278) and the Williamsburgh Bridge (connecting to ManhattanManhattanManhattan is the oldest and the most densely populated of the five boroughs of New York City. Located primarily on the island of Manhattan at the mouth of the Hudson River, the boundaries of the borough are identical to those of New York County, an original county of the state of New York...
) - The elevated sections of the Delhi MetroDelhi MetroDelhi Metro is a rapid transit system serving Delhi, Gurgaon, Noida and Ghaziabad in the National Capital Region of India. It is one of the largest metro networks in the world. The network consists of six lines with a total length of with 142 stations of which 35 are underground...
- The I-35W Saint Anthony Falls Bridge in Minneapolis, MNMinnesotaMinnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, is notable primarily for the bridge it replaced: I-35W Mississippi River bridge which collapsed on August 1, 2007. - Canada's Confederation BridgeConfederation BridgeThe Confederation Bridge is a bridge spanning the Abegweit Passage of Northumberland Strait, linking Prince Edward Island with mainland New Brunswick, Canada. It was commonly referred to as the "Fixed Link" by residents of Prince Edward Island prior to its official naming. Construction took place...
linking the provinces of Prince Edward IslandPrince Edward IslandPrince Edward Island is a Canadian province consisting of an island of the same name, as well as other islands. The maritime province is the smallest in the nation in both land area and population...
and New BrunswickNew BrunswickNew Brunswick is one of Canada's three Maritime provinces and is the only province in the federation that is constitutionally bilingual . The provincial capital is Fredericton and Saint John is the most populous city. Greater Moncton is the largest Census Metropolitan Area...
.
Further reading
- LoBuono, J. (2005). "Assembly required-The instructions for building New Jersey’s first segmental bridge." Chicago, Illinois: GoBridges.com. September/October. Published October 18, 2005 at http://www.gobridges.com/article.asp?id=770
- (2006) "Design & Construction of Ngong Shuen Chau Viaduct" International Conference on Bridge Engineering – Challenges in the 21st Century, Hong Kong, 1 ~ 3 November 2006 http://www.ywlgroup.com/articles.html
- (2007) "Construction of the Precast Segmental Approach - Structures for Sutong Bridge" ICE Conference 2007, Beijing http://www.ywlgroup.com/articles.html
Related sites
- http://www.fhwa.dot.gov/bridge/segmental/index.htm
- http://www.asbi-assoc.org/
- http://www.mcnarybergeron.com/
- http://www.pbworld.com/news_events/publications/network/issue_57/57_03_murilloj_briefhistoryseg.asp
- http://www.pbworld.com/news_events/publications/network/issue_28/28_16_wahlp_constructionsequence.asp
- http://www.polito.it/creepanalysis