Twin bridges

The Delaware Memorial Bridge twin-span suspension bridge

Twin bridges are a set of two bridges 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.^[1] 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.

Twin-span bridges may or may not have been constructed at the same time, and may not be identical or even the same type of bridge. Many but not all twin bridges carry one-way pairs of traffic.

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.^[1]

List


	First span	Second span	Notes
Carquinez Bridge	1958 cantilever span	2003 suspension span	2003 span replaced a 1927 cantilever span
Chesapeake Bay Bridge	1952 suspension and cantilever spans	1973 suspension and cantilever spans
Delaware Memorial Bridge	1951 suspension span	1968 suspension span
Donald and Morris Goodkind Bridges	1929 Art Deco arch span	1976 steel bridge
Crescent City Connection	1958 cantilever span	1988 cantilever span
Lake Pontchartrain Causeway	1956 causeway	1969 causeway
Bi-State Vietnam Gold Star Bridges	1932 cantilever span	1965 cantilever span
Blue Water Bridge	1938 cantilever span	1997 tied arch span
Québec Bridge and Pierre Laporte Bridge	1919 cantilever span	1970 suspension span	Not a one-way pair
Tacoma Narrows Bridge	1950 suspension span	2007 suspension span	1950 span replaced a collapsed 1940 span
Tappan Zee Bridge	2017 cable-stayed spans
Newburgh–Beacon Bridge	1963 continuous truss span	1980 continuous truss span
Thaddeus Kosciusko Bridge	1961 through-arch spans
Kosciuszko Bridge	2017 cable-stayed span	2019 cable-stayed span
South Grand Island Bridge	1935 truss-arch span	1962 truss-arch span
John F. Kennedy Memorial Bridge and Abraham Lincoln Bridge	1963 cantilever span	2015 cable-stayed span
Chaplain Washington and Harry Laderman Bridges	1952 causeway	1970 causeway	Not a one-way pair; each bridge carries bidirectional traffic for one of the two spurs of the New Jersey Turnpike
Fairfax and Platte Purchase Bridges	1934 continuous truss span	1957 continuous truss span	Both demolished and replaced with U.S. Route 69 Missouri River Bridge
Liberty Bend Bridge	1949 continuous truss span	2001 continuous truss span
New Buck O'Neil Bridge	2024 beam spans
14th Street bridges	Five spans, see article
Maria Skłodowska-Curie Bridge	Three 2012 beam spans
Sir Leo Hielscher Bridges	1986 cantilever box girder span	2010 cantilever box girder span
Iron Cove Bridge	1955 steel truss bridge	2011 box girder span

References

^ ^a ^b Guidance for Good Bridge Design (Google books). Luasanne, Switzerland: Fédération Internationale du Béton. 2000. p. 15. ISBN 2-88394-049-5. Retrieved October 3, 2009. In order to ensure better management and maintenance of such structures, but also in order to limit the risk that the bridge must be closed in cases of serious highway accidents, most authorities impose a solution of twin bridges which are totally independent of each other. It is clear that in most common cases this is a reasonable and judicious solution.

[Good_Bridges-1] Guidance for Good Bridge Design (Google books). Luasanne, Switzerland: Fédération Internationale du Béton. 2000. p. 15. ISBN 2-88394-049-5. Retrieved October 3, 2009. In order to ensure better management and maintenance of such structures, but also in order to limit the risk that the bridge must be closed in cases of serious highway accidents, most authorities impose a solution of twin bridges which are totally independent of each other. It is clear that in most common cases this is a reasonable and judicious solution.

[1]