Ancestor | Beam bridge |
---|---|
Related | Trestle bridge, truss bridge, moon bridge |
Descendant | Box girder bridge, Plate girder bridge |
Carries | Pedestrians, automobiles, trucks, light rail, heavy rail |
Span range | Short, Medium |
Material | Iron, wood, concrete |
Movable | No |
Design effort | low |
Falsework required | No |
A girder bridge is a bridge that uses girders as the means of supporting its deck. [1] The two most common types of modern steel girder bridges are plate and box.[ citation needed ]
The term "girder" is often used interchangeably with "beam" in reference to bridge design. [2] [3] [4] [5] However, some authors define beam bridges slightly differently from girder bridges. [6]
A girder may be made of concrete or steel. Many shorter bridges, especially in rural areas where they may be exposed to water overtopping and corrosion, utilize concrete box girder. The term "girder" is typically used to refer to a steel beam. In a beam or girder bridge, the beams themselves are the primary support for the deck, and are responsible for transferring the load down to the foundation. Material type, shape, and weight all affect how much weight a beam can hold. Due to the properties of the second moment of area, the height of a girder is the most significant factor to affect its load capacity. Longer spans, more traffic, or wider spacing of the beams will all directly result in a deeper beam. In truss and arch-style bridges, the girders are still the main support for the deck, but the load is transferred through the truss or arch to the foundation. These designs allow bridges to span larger distances without requiring the depth of the beam to increase beyond what is practical. However, with the inclusion of a truss or arch the bridge is no longer a true girder bridge.
Girder bridges have existed for millennia in a variety of forms depending on resources available. The oldest types of bridges are the beam, arch and swing bridges, and they are still built today. These types of bridges have been built by human beings since ancient times, with the initial design being much simpler than what we utilize today. As technology advanced the methods were improved and were based on the utilization and manipulation of rock, stone, mortar and other materials that would serve to be stronger and longer.
In ancient Rome, the techniques for building bridges included the driving of wooden poles to serve as the bridge columns and then filling the column space with various construction materials. The bridges constructed by Romans were at the time basic but very dependable and strong while serving a very important purpose in social life.
As the Industrial Revolution came and went, new materials with improved physical properties were utilized; and wrought iron was replaced with steel due to steel's greater strength and larger application potential.
All bridges consist of two main parts: the substructure, and the superstructure. The superstructure is everything from the bearing pads, up - it is what supports the loads and is the most visible part of the bridge. The substructure is the foundation which transfers loads from the superstructure to the ground. Both must work together to create a strong, long-lasting bridge.
The superstructure consists of several parts:
The substructure is made of multiple parts as well:
Beam bridges are the simplest structural forms for bridge spans supported by an abutment or pier at each end. No moments are transferred throughout the support, hence their structural type is known as simply supported.
A plate girder bridge is a bridge supported by two or more plate girders.
Falsework consists of temporary structures used in construction to support a permanent structure until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework includes temporary support structures for formwork used to mold concrete in the construction of buildings, bridges, and elevated roadways.
A girder is a support beam used in construction. It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing flanges separated by a stabilizing web, but may also have a box shape, Z shape, or other forms. Girders are commonly used to build bridges.
An orthotropic bridge or orthotropic deck is typically one whose fabricated deck consists of a structural steel deck plate stiffened either longitudinally with ribs or transversely, or in both directions. This allows the fabricated deck both to directly bear vehicular loads and to contribute to the bridge structure's overall load-bearing behaviour. The orthotropic deck may be integral with or supported on a grid of deck framing members, such as transverse floor beams and longitudinal girders. All these various choices for the stiffening elements, e.g., ribs, floor beams and main girders, can be interchanged, resulting in a great variety of orthotropic panels.
The Svinesund Bridge is a through arch bridge crossing Iddefjord at Svinesund, and joining Sweden and Norway. Svinesund is a sound separating the Swedish municipality of Strömstad from the Norwegian municipality of Halden, and thus it is the border between Norway and Sweden in this region. The bridge is the westernmost border crossing between the two countries and carries the European route E6 which is a major traffic route in the area, connecting Oslo and the rest of Norway with Gothenburg, Malmö, Copenhagen and the rest of Europe.
The M5 is an expressway in the City of Cape Town Metropolitan Municipality, South Africa. It connects Milnerton on the Western Seaboard in the north to Muizenberg in the south, and crosses both the N1 and the N2. For part of its length, from the N1 interchange to Plumstead, it is a limited-access freeway (motorway). From Mowbray to Muizenberg, it is parallel to the M4 Main Road.
A tied-arch bridge is an arch bridge in which the outward horizontal forces of the arch(es) caused by tension at the arch ends to a foundation are countered by equal tension of its own gravity plus any element of the total deck structure such great arch(es) support. The arch(es) have strengthened chord(s) that run to a strong part of the deck structure or to independent tie-rods below the arch ends.
A box or tubular girder is a girder that forms an enclosed tube with multiple walls, as opposed to an I- or H-beam. Originally constructed of riveted wrought iron, they are now made of rolled or welded steel, aluminium extrusions or prestressed concrete.
Locke Avenue Bridge is located on Locke Avenue, a two-lane rural route located at the northwest corner of Swedesboro in Gloucester County, New Jersey. This roadway runs generally north-south, connecting Auburn Road with U.S. Route 322. The posted speed limit on Locke Avenue is 40 miles per hour (60 km/h).
A deck is the surface of a bridge. A structural element of its superstructure, it may be constructed of concrete, steel, open grating, or wood. Sometimes the deck is covered by a railroad bed and track, asphalt concrete, or other form of pavement for ease of vehicle crossing. A concrete deck may be an integral part of the bridge structure or it may be supported with I-beams or steel girders.
The Hadley Parabolic Bridge, often referred to locally as the Hadley Bow Bridge, carries Corinth Road across the Sacandaga River in Hadley, New York, United States. It is an iron bridge dating from the late 19th century.
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 Old Rhine Bridge at Konstanz spans the Seerhein. It is a combined road and railway bridge. In addition to one track of the High Rhine Railway at kilometer 413.5, it carries the Konzilstraße, the road that connects the borough of Petershausen with the city centre. The road bridge carries two lanes into the city center and three lanes in the other direction. Additionally, there is a bicycle lane in both directions on the left and a sidewalk on the right. In the 19th century, distance markers were placed along the Rhine; they start counting kilometers at this bridge.
The Adomi Bridge is a latticed steel arch suspension bridge crossing the Volta River at Atimpoku in Ghana in West Africa. It is the first permanent bridge to span the Volta River, which drains south into the Gulf of Guinea, and is Ghana's longest suspension bridge. It provides the main road passage, just south of the Akosombo Dam, between the Eastern Region and the Volta Region of Ghana. It was opened in 1957 by Kwame Nkrumah, Ghana's first president. The iconic crescent-shaped arch bridge is featured in Ghanaian stamps and currency.
A balloon flange girder or (colloquially) balloon topper is a form of vertical I-beam wrought iron plate girder, where the top flange, instead of being a simple flat plate, is extended into a hollow tube. When a girder is subjected to a positive bending moment the top flange acts in compression making a flat plate flange more susceptible to local buckling than the balloon flange is.
A Rigid-frame bridge is a bridge in which the superstructure and substructure are rigidly connected to act as a continuous unit. Typically, the structure is cast monolithically, making the structure continuous from deck to foundation. The connections between members are rigid connections which transfer bending moment, axial forces, and shear forces. A bridge design consisting of a rigid frame can provide significant structural benefits, but can also be difficult to design and/or construct.
A launching gantry is a special-purpose mobile gantry crane used in bridge construction, specifically segmental bridges that use precast box girder bridge segments or precast girders in highway and high-speed rail bridge construction projects. The launching gantry is used to lift and support bridge segments or girders as they are placed while being supported by the bridge piers instead of the ground.
The Fisher Covered Railroad Bridge is a covered bridge in Wolcott, Vermont. Built in 1908, it originally carried the St. Johnsbury and Lamoille County Railroad line over the Lamoille River. Now closed, it was the last covered bridge in Vermont to carry railroad traffic, and is a rare surviving example in the state of a double Town lattice truss. It was listed on the National Register of Historic Places in 1974.
The Thetford Center Covered Bridge is a historic covered bridge, carrying Tucker Hill Road across the Ompompanoosuc River in Thetford, Vermont. It is the state's only known example of the Haupt patent truss system. It was listed on the National Register of Historic Places in 1974.