arch bridge definition
Arch Bridge. a bridge with span structures, the basic components of which are arches or vaults. Characteristic traits of an arch bridge are the transfer to the supports not only of the vertical but also the horizontal stresses (thrust), as well as the strain, primarily of compression, on the arches or vaults. Stone arch bridges have been known since the most ancient times. Modern arch bridges are built, for the most part, of reinforced concrete or of steel. An example is the railroad arch bridge across the Oka River at the city of Gorky. This is most common for bridges made of stone or concrete. Once the complete arch is in place, the temporary wooden structure can be removed. Ancient stone bridges relied on the final top stone, or keystone, to be put into place for the bridge to experience the compression that would make it strong. Arch bridges are one of the oldest types of bridges and have been aroundd for thousands of years. Arch bridges have great natural strength. They were originally built of stone or brick but these days are built of reinforced concrete or steel. The introduction of these new materials allow arch bridges to be longer with lower spans. The load at the top of the key stone makes each stone on the arch of the bridge press on the one next to it. This happens until the push is applied to the end supports or abutments, which are enbedded in the ground. The ground around the abutments is squeezed and pushes back on the abutments. For every action there is an equal and opposite reaction. The ground which pushes back on the abutments creates a resistance which is passed from stone to stone, until it is eventually pushing on the key stone which is supporting the load. Instead of pushing straight down, the load of an arch bridge is carried outward along the curve of the arch to the supports at each end. The weight is transferred to the supports at either end. These supports, called the abutments, carry the load and keep the ends of the bridge from spreading out. Extra support is also often placed along the abutments, or sides, of the structure to keep the arch from bending outwards when heavy loads press down on it, but in most cases nothing needs to touch the ground at any point along the span. An arch bridge is a type of architectural structure that relies on a curved, semi-circular shape for support. Most arches distribute weight equally and are an attractive option for bridges because they can span great distances without needing posts or other weight-bearing mechanisms to be sunk into the ground. Possibly the oldest existing arch bridge is the Mycenaean Arkadiko bridge in Greece from about 1300 BC. The stone corbel arch bridge is still used by the local populace. The well-preserved Hellenistic Eleutherna Bridge has a triangular corbel arch. Alexander Hamilton Bridge. This type of bridge comprises an arch where the deck is completely above the arch. The area between the arch and the deck is known as the spandrel. If the spandrel is solid, usually the case in a masonry or stone arch bridge, the bridge is called a closed-spandrel arch bridge. A viaduct (a long bridge) may be made from a series of arches, although other more economical structures are typically used today.
A type of architectural structure that relies on a curved, semi-circular shape for support.