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TOPIC: BRIDGE TYPES TOPIC: BRIDGE TYPES 1. Introduce 1. Introduce  A bridge is a structure built to span physical A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, obstacles such as a body of water, valley, or road, for the purpose of providing passage over the for the purpose of providing passage over the obstacle. Designs of bridges vary depending on the obstacle. Designs of bridges vary depending on the function of the bridge, the nature of the terrain function of the bridge, the nature of the terrain where the bridge is constructed, the material used to where the bridge is constructed, the material used to make it and the funds available to build it. make it and the funds available to build it.  There are six main types of bridges: beam bridges, There are six main types of bridges: beam bridges, truss bridges, arch bridges, cantilever bridges, truss bridges, arch bridges, cantilever bridges, suspension bridges and cable-stayed bridges. suspension bridges and cable-stayed bridges. Illustration for bridges type Illustration for bridges type I. Beam bridges I. Beam bridges  Beam bridges are the most simple of structural Beam bridges are the most simple of structural forms being supported by an abutment at each forms being supported by an abutment at each end of the deck. No moments are transferred end of the deck. No moments are transferred through the support hence their structural type is through the support hence their structural type is known as simply supported. known as simply supported.  The simplest beam bridge could be a slab of The simplest beam bridge could be a slab of stone, or a plank of wood laid across a stream. stone, or a plank of wood laid across a stream. Bridges designed for modern infrastructure will Bridges designed for modern infrastructure will usually be constructed of steel or reinforced usually be constructed of steel or reinforced concrete, or a combination of both. The concrete concrete, or a combination of both. The concrete used can either be reinforced, prestressed or used can either be reinforced, prestressed or post-tensioned. post-tensioned.  Types of construction could include having many Types of construction could include having many beams side by side with a deck across the top of beams side by side with a deck across the top of them, to a main beam either side supporting a them, to a main beam either side supporting a deck between them. The main beams could be I- deck between them. The main beams could be I- beams, trusses, or box girders. They could be beams, trusses, or box girders. They could be half-through, or braced across the top to create a half-through, or braced across the top to create a through bridge. through bridge.  Beam bridges are often only used for really short Beam bridges are often only used for really short distances because, unlike truss bridges, they have distances because, unlike truss bridges, they have no built in supports. The only supports are no built in supports. The only supports are provided by piers. provided by piers. Feiyun River Bridge, Zhejiang Province The beam bridges famous The beam bridges famous Rio-niteroiBridge SevenMileBridge II. Truss bridges II. Truss bridges  A truss bridge is a bridge A truss bridge is a bridge composed of connected composed of connected elements(typically straight) elements(typically straight) which may be stressed from which may be stressed from tension, compression, or tension, compression, or sometimes both in response to sometimes both in response to dynamic loads. Truss bridges dynamic loads. Truss bridges are one of the oldest types of are one of the oldest types of modern bridges. The basic modern bridges. The basic types of truss bridges shown in types of truss bridges shown in this article have simple designs this article have simple designs which could be easily analyzed which could be easily analyzed by nineteenth and early by nineteenth and early twentieth century engineers. A twentieth century engineers. A truss bridge is economical to truss bridge is economical to construct owing to its efficient construct owing to its efficient use of materials. use of materials. The truss bridges famous The truss bridges famous ErieCanalRRBridge TrangTien bridge III. Arch bridges III. Arch bridges  An arch bridge is a bridge with abutments An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch at each end shaped as a curved arch. Arch bridges work by transferring the weight of bridges work by transferring the weight of the bridge and its loads partially into a the bridge and its loads partially into a horizontal thrust restrained by the horizontal thrust restrained by the abutments at either side. A viaduct (a long abutments at either side. A viaduct (a long bridge) may be made from a series of bridge) may be made from a series of arches, although other more economical arches, although other more economical structures are typically used today. structures are typically used today.  Arch bridge: construction that allows Arch bridge: construction that allows automobiles to travel between two points automobiles to travel between two points separated by an obstacle. separated by an obstacle. Portal frame: construction that carries the Portal frame: construction that carries the weight of a suspended load to the ground. weight of a suspended load to the ground. Arch: arched vault that is supported by Arch: arched vault that is supported by the abutments. the abutments. Deck: platform of the bridge. Deck: platform of the bridge. Lower chord: lower supporting piece. Lower chord: lower supporting piece. Upper chord: upper supporting piece. Upper chord: upper supporting piece. Pile: masonry pylon that serves as Pile: masonry pylon that serves as support. support. The arch bridges famous The arch bridges famous Si-o-sePolbridge,Iran Fredrikstad_BridgeacrossGlomma01 Fredrikstad Na Uy HarlemRiverBridges (New York , Mỹ ) . six main types of bridges: beam bridges, There are six main types of bridges: beam bridges, truss bridges, arch bridges, cantilever bridges, truss bridges, arch bridges, cantilever bridges,. The beam bridges famous The beam bridges famous Rio-niteroi Bridge SevenMile Bridge II. Truss bridges II. Truss bridges  A truss bridge is a bridge A truss bridge is a bridge composed. suspension bridges and cable-stayed bridges. suspension bridges and cable-stayed bridges. Illustration for bridges type Illustration for bridges type I. Beam bridges I. Beam bridges  Beam bridges