A bridge is a structure built to span a physical obstacle without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it.
A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements, usually forming triangular units. The connected elements, typically straight, may be stressed from tension, compression, or sometimes both in response to dynamic loads. There are several types of truss bridges, including some with simple designs that were among the first bridges designed in the 19th and early 20th centuries. A truss bridge is economical to construct primarily because it uses materials efficiently.
Navajo Bridge is the name of twin steel spandrel arch bridges that cross the Colorado River in the Grand Canyon National Park in northern Coconino County, Arizona, United States. The newer of the two spans carries vehicular traffic on U.S. Route 89A (US 89A) over Marble Canyon between Bitter Springs and Jacob Lake, allowing travel into a remote Arizona Strip region north of the Colorado River including the North Rim of Grand Canyon National Park.
Gustav Lindenthal was a civil engineer who designed the Queensboro and Hell Gate bridges in New York City, among other bridges. Lindenthal's work was greatly affected by his pursuit for perfection and his love of art. Having received little formal education and no degree in civil engineering, Lindenthal based his work on his prior experience and techniques used by other engineers of the time.
The Fort Pitt Bridge is a steel, double-decked bowstring arch bridge that spans the Monongahela River near its confluence with the Allegheny River in Pittsburgh, Pennsylvania. It carries Interstate 376 between the Fort Pitt Tunnel and Downtown Pittsburgh. Opened in June 1959 as a replacement for the Point Bridge, the Fort Pitt Bridge was the world's first computer-designed bowstring arch bridge and double-decked bowstring arch bridge. The bridge is known for its difficult lane changes, especially on the lower level, often requiring people to go from the extreme left lane across two lanes to the extreme right lane in only 700 feet. The upper level is more forgiving for some routes but still requires a full span lane change in 700 feet to get from the south side entrance to the downtown exits.
Robert Maillart was a Swiss civil engineer who revolutionized the use of structural reinforced concrete with such designs as the three-hinged arch and the deck-stiffened arch for bridges, and the beamless floor slab and mushroom ceiling for industrial buildings. His Salginatobel (1929–1930) and Schwandbach (1933) bridges changed the aesthetics and engineering of bridge construction dramatically and influenced decades of architects and engineers after him. In 1991 the Salginatobel Bridge was declared an International Historic Civil Engineering Landmark by the American Society of Civil Engineers.
A stressed ribbon bridge is a tension structure similar in many ways to a simple suspension bridge. The suspension cables are embedded in the deck, which follows a catenary arc between supports. As with a simple suspension bridge, the weight is taken by the suspension cables, but unlike the simple span, the deck or ribbon is stressed in compression, which adds to the stiffness of the structure. The supports in turn sustain upward-thrusting arcs that allow the grade to be changed between spans. Such bridges are typically made from concrete reinforced by steel tensioning cables. Where such bridges carry vehicle traffic, a certain degree of stiffness is required to prevent excessive flexure of the structure, obtained by stressing the concrete in compression.
Christian Menn was a renowned Swiss civil engineer and bridge designer. He was involved in the construction of around 100 bridges worldwide, but the focus of his work was in eastern Switzerland, especially in canton Graubünden. He continued the tradition of and had a decisive influence on Swiss bridge building. The technical and aesthetic possibilities of prestressed concrete were most fully realized with his bridges in Switzerland.
The Margaret Hunt Hill Bridge is a bridge in Dallas, Texas, that spans the Trinity River. The bridge is named for Margaret Hunt Hill, an heiress and philanthropist. The bridge was constructed as part of the Trinity River Project. Designed by Santiago Calatrava, it is one of three such bridges planned to be built over the Trinity; the second, the Margaret McDermott Bridge, is completed; the third cancelled. The span parallels the Ronald Kirk Bridge, a walking bridge that was previously the Continental Avenue bridge.
A girder bridge is a bridge that uses girders as the means of supporting its deck. The two most common types of modern steel girder bridges are plate and box.
The Fort Henry Bridge is a crossing of the Ohio River main channel in Wheeling, West Virginia. The tied-arch bridge carries two lanes in each direction of Interstate 70 (I-70), U.S. Route 40 (US 40), and US 250. The bridge opened after four years of construction work on September 8, 1955, costing $6.8 million, $1.8 million over budget. The bridge, along with the aging Wheeling Suspension Bridge, are the only two road links from Wheeling Island to downtown Wheeling, although this is the only one that allows vehicular traffic. In 2009, the structure carried an average of over 60,000 vehicles per day.
The French King Bridge is the three-span "cantilever arch" bridge that crosses the Connecticut River on the border between the towns of Erving and Gill, Massachusetts, United States. The bridge, part of Massachusetts Route 2, carries automobile, bicycle, and pedestrian traffic and is owned and managed by the Massachusetts Department of Transportation (MassDOT).
Miguel Rosales is president and principal designer of Rosales + Partners, an architecture firm based in Boston, Massachusetts. He specializes in bridge aesthetics and design. Some examples of these bridges include; Phyllis J. Tilley Memorial Bridge, Christina and John Markey Memorial Pedestrian Bridge, and Liberty Bridge at Falls Park on the Reedy River.
The Hampden County Memorial Bridge is a reinforced-concrete arch bridge that spans the Connecticut River between Springfield, Massachusetts and West Springfield, Massachusetts, constructed in 1922. The bridge is owned by Massachusetts Highway Department and is located on Massachusetts Route 147. It spans 209 feet (64 m) and rises 29.71 feet (9.06 m) above the river.
The Igor I. Sikorsky Memorial Bridge carries the controlled-access Merritt Parkway over the Housatonic River, between Stratford and Milford, Connecticut.
The Bellows Falls Arch Bridge was a three-hinged steel through arch bridge over the Connecticut River between Bellows Falls, Vermont and North Walpole, New Hampshire. It was structurally significant as the longest arch bridge in the United States when it was completed in 1905.
The Godavari Arch Bridge is a bowstring-girder bridge that spans the Godavari River in Rajahmundry, India. It is the latest of the three bridges that span the Godavari river at Rajahmundry. The Havelock Bridge being the earliest, was built in 1897, and having served its full utility, was decommissioned in 1997. The second bridge known as the Godavari Bridge is a truss bridge and is India's third longest road-cum-rail bridge crossing a water body.
The Margaret McDermott Bridge is a conventional concrete pier-and-beam freeway bridge with cable-stayed bike lines over the Trinity River in Dallas, Texas. It replaced the late-1950s to early-1960s Interstate 30 (I-30) bridge, which reached its end of life. It was partially designed by Santiago Calatrava, and is part of the Trinity River Project and the Horseshoe Project. It was named for Margaret McDermott, an area philanthropist.
The Moody Pedestrian Bridge is a pedestrian bridge in Austin, Texas on the campus of the University of Texas at Austin. It connects two buildings within the Moody College of Communication across a street.
