Twin bridges

For other uses, see Twin Bridges (disambiguation).

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.

The Delaware Memorial Bridge twin-span suspension bridge

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

Bridge		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