Twin bridges are a set of two

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...

s running parallel to each other. A pair of twin bridges is often referred to collectively as a twin-span or dual-span bridge. Twin bridges are independent structures and each bridge has its own superstructure, substructure, and

foundation Foundation may refer to: * Foundation (nonprofit), a type of charitable organization ** Foundation (United States law), a type of charitable organization in the U.S. ** Private foundation, a charitable organization that, while serving a good cause ...

. Bridges of this type are often created by building a new bridge parallel to an existing one in order to increase the traffic capacity of the crossing. While most twin-span bridges consist of two identical bridges, this is not always the case. For a bridge owner, twin bridges can improve the maintenance and management of the structures. For motorists, twin bridges can limit the risk that both directions of traffic will be disrupted by an accident.

Examples

* Carquinez Bridge – original cantilever span built in 1927 and later twinned in 1958; a newer suspension span was built in 2003 to replace the original 1927 span, which was later demolished in 2007. *

Chesapeake Bay Bridge The Chesapeake Bay Bridge (also known locally as the Bay Bridge) is a major dual-span bridge in the U.S. state of Maryland. Spanning the Chesapeake Bay, it connects the state's rural Eastern Shore region with the urban Western Shore, between ...

– twin suspension spans with notable visual differences in construction techniques. *

Delaware Memorial Bridge The Delaware Memorial Bridge is a dual-span suspension bridge crossing the Delaware River. The toll bridges carry Interstate 295 and U.S. Route 40 and is also the link between Delaware and New Jersey. The bridge was designed by the firm kn ...

– identical twin spans built 18 years apart from one another. * Maria Skłodowska-Curie Bridge – almost identical triplets. *

Donald and Morris Goodkind Bridges The Donald and Morris Goodkind Bridges are a pair of bridges on U.S. Route 1 in the U.S. state of New Jersey. The bridges cross the Raritan River, connecting Edison on the north bank with New Brunswick on the south. The northbound span, a concr ...

– original

Art Deco Art Deco, short for the French ''Arts Décoratifs'', and sometimes just called Deco, is a style of visual arts, architecture, and product design, that first appeared in France in the 1910s (just before World War I), and flourished in the Unite ...

arch span built in 1929; newer steel bridge built in 1976. *

Crescent City Connection The Crescent City Connection (CCC), formerly the Greater New Orleans Bridge (GNO), is a pair of cantilever bridges that carry U.S. Highway 90 Business (US 90 Bus.) over the Mississippi River in New Orleans, Louisiana, United States. They ...

– original cantilever span opened in 1958; parallel span opened in 1988 *

Lake Pontchartrain Causeway The Lake Pontchartrain Causeway (french: Chaussée du lac Pontchartrain), also known simply as The Causeway, is a fixed link composed of two parallel bridges crossing Lake Pontchartrain in southeastern Louisiana, United States. The longer of th ...

– the longest twin-span bridge in the world. Original span opened in 1956, second span in 1969 * Bi-State Vietnam Gold Star Bridges – pair of cantilever bridges over the Ohio River. First span opened in 1932, second span in 1965. *

Blue Water Bridge The Blue Water Bridge is a twin-span international bridge across the St. Clair River that links Port Huron, Michigan, United States, and Sarnia, Ontario, Canada. The Blue Water Bridge connects Highway 402 in Ontario with both Interstate 69 ...

- Border crossing between Port Huron, Michigan (United States) and Sarnia, Ontario (Canada). * Québec Bridge *

Sir Leo Hielscher Bridges The Sir Leo Hielscher Bridges are a side-by-side pair of road bridges on the Gateway Motorway (M1), which skirts the eastern suburbs of Brisbane, Queensland, Australia. The western bridge carries traffic to the north and the eastern bridge car ...

Iron Cove Bridge The Iron Cove Bridge is a heritage-listed road bridge that carries Victoria Road (A40) across Iron Cove, linking the Sydney suburbs of Drummoyne to Rozelle in the City of Canada Bay local government area of New South Wales, Australia. Curren ...

Tacoma Narrows Bridge The Tacoma Narrows Bridge is a pair of twin suspension bridges that span the Tacoma Narrows strait of Puget Sound in Pierce County, Washington. The bridges connect the city of Tacoma with the Kitsap Peninsula and carry State Route 16 (know ...

Daniel Carter Beard Bridge The Daniel Carter Beard Bridge (also known colloquially as the Big Mac Bridge), is a yellow twin span steel bowstring arch bridge crossing the Ohio River in Cincinnati, Ohio. It carries Interstate 471 between Cincinnati, Ohio, and Newport, Kent ...

* Tappan Zee Bridge – originally a single span in 1955, rebuilt into a new double span in 2017, old bridge demolished *

Newburgh–Beacon Bridge The Hamilton Fish Newburgh–Beacon Bridge is a cantilever toll bridge that spans the Hudson River in New York State. The bridge carries Interstate 84 (I-84) and New York State Route 52 (NY 52) between Newburgh and Beacon and c ...

– originally a single span in 1963, 2nd span added in 1980 *

Thaddeus Kosciusko Bridge The Thaddeus Kosciusko Bridge, commonly referred to as the Twin Bridges, or just "The Twins", located in the United States, is a pair of identical through arch bridges, made of steel, which span the Mohawk River between the towns of Colonie, ...

– commonly referred to as the "Twin Bridges", or just "The Twins" *

Kosciuszko Bridge The Kosciuszko Bridge is a cable-stayed bridge over Newtown Creek in New York City, connecting Greenpoint in Brooklyn to Maspeth in Queens. The bridge consists of a pair of cable-stayed bridge spans: the eastbound span opened in April 2017 ...

– twin cable-stayed spans, with their pylons mirrored on opposite sides of Newtown Creek *

South Grand Island Bridge The South Grand Island Bridge is a pair of twin two-lane truss arch bridges spanning the Niagara River between Tonawanda and Grand Island in New York, United States. Each bridge carries one direction of Interstate 190 (I-190) and New Y ...

References

Structural engineering Bridge design Duos {{Bridge-type-stub