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    What Is A BRIDGE

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    Ashish Singh
    A bridge is a structure that spans a gap or barrier, usually to allow transportation such as vehicles, trains or pedestrians to pass. Bridges carry roads or railways over rivers, valleys or other obstacles. The capacity of a bridge system is controlled by the bridge's width and strength, limiting the volume and weight of traffic it can accommodate. Bridges also have the highest cost per mile compared to approach roads. Different bridge types include beam, arch, truss, suspension and cable-stayed bridges, with materials including steel, concrete, wood and stone. Suspension bridges are described as having main cables supported by towers that transfer loads through hangers to the deck.

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    What Is A BRIDGE

    Uploaded by

    Ashish Singh
    42 views5 pages
    A bridge is a structure that spans a gap or barrier, usually to allow transportation such as vehicles, trains or pedestrians to pass. Bridges carry roads or railways over rivers, valleys or other obstacles. The capacity of a bridge system is controlled by the bridge's width and strength, limiting the volume and weight of traffic it can accommodate. Bridges also have the highest cost per mile compared to approach roads. Different bridge types include beam, arch, truss, suspension and cable-stayed bridges, with materials including steel, concrete, wood and stone. Suspension bridges are described as having main cables supported by towers that transfer loads through hangers to the deck.

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    A bridge is a structure that spans a gap or barrier, usually to allow transportation such as vehicles, trains or pedestrians to pass. Bridges carry roads or railways over rivers, valleys or other obstacles. The capacity of a bridge system is controlled by the bridge's width and strength, limiting the volume and weight of traffic it can accommodate. Bridges also have the highest cost per mile compared to approach roads. Different bridge types include beam, arch, truss, suspension and cable-stayed bridges, with materials including steel, concrete, wood and stone. Suspension bridges are described as having main cables supported by towers that transfer loads through hangers to the deck.

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    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    42 views5 pages

    What Is A BRIDGE

    Uploaded by

    Ashish Singh
    A bridge is a structure that spans a gap or barrier, usually to allow transportation such as vehicles, trains or pedestrians to pass. Bridges carry roads or railways over rivers, valleys or other obstacles. The capacity of a bridge system is controlled by the bridge's width and strength, limiting the volume and weight of traffic it can accommodate. Bridges also have the highest cost per mile compared to approach roads. Different bridge types include beam, arch, truss, suspension and cable-stayed bridges, with materials including steel, concrete, wood and stone. Suspension bridges are described as having main cables supported by towers that transfer loads through hangers to the deck.

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    © All Rights Reserved
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    of 5

    What is a BRIDGE?

    Bridge is a structure which covers a gap

    Generally bridges carry a road or railway across a natural or artificial obstacle


    such as, a river, canal or another railway or another road

    Bridge is a structure corresponding to the heaviest responsibility in carrying a


    free flow of transport and is the most significant component of a
    transportation system in case of communication over spacings/gaps for
    whatever reason such as aquatic obstacles, valleys and gorges etc.

    It Controls the Capacity of the System

    If the width of a bridge is insufficient to carry the number of lanes required


    to handle the traffic volume, the bridge will be a constriction to the flow of
    traffic. If the strength of a bridge is deficient and unable to carry heavy
    trucks, load limits will be posted and truck traffic will be rerouted.

    The bridge controls both the volume and weight of the traffic carried by the
    transportation system.

    Highest Cost per Mile of the System


    Bridges are expensive. The typical cost per mile of a bridge is many times
    that of the approach roads to the bridge.`
    Since, bridge is the key element in a transportation system,
    balance must be achieved between handling future traffic
    volume and loads and the cost of heavier and wider bridge
    structure.

    Classification of Bridges
    Material Steel Concrete Wood Hybrid
    Usage Pedestrian Highway
    Span

    Short

    Medium

    Structural Form Slab


    Stayed

    Stone/Brick

    Railroad

    Long
    Girder

    Truss

    Arch Suspension

    Cable-

    Structural Arrangement

    Distinctive Features of Suspension Bridge

    Major element is a flexible cable, shaped and supported in such a way that it
    transfers the loads to the towers and anchorage

    This cable is commonly constructed from High Strength wires, either spun in
    situ or formed from component, spirally formed wire ropes. In either case
    allowable stresses are high of the order of 600 MPA

    The deck is hung from the cable by Hangers constructed of high strength
    ropes in tension

    As in the long spans the Self-weight of the structures becomes significant, so


    the use of high strength steel in tension, primarily in cables and secondarily
    in hangers leads to an economical structure.

    The economy of the cable must be balanced against the cost of the
    associated anchorage and towers. The anchorage cost may be high where
    foundation material is poor

    The main cable is stiffened either by a pair of stiffening trusses or by a


    system of girders at deck level.

    This stiffening system serves to (a) control aerodynamic movements and (b)
    limit local angle changes in the deck. It may be unnecessary in cases where
    the dead load is great.

    The complete structure can be erected without intermediate staging from the
    ground

    The main structure is elegant and neatly expresses its function.

    It is the only alternative for spans over 600m, and it is generally regarded as
    competitive for spans down to 300m. However, shorter spans have also been
    built, including some very attractive pedestrian bridges

    The height of the main towers can be a disadvantage in some areas; for
    example, within the approach road for an AIRPORT

    Extra Large (Long) Span Bridges


    (Over 150m)
    Cable Stayed Bridge
    Suspension Bridge

    Components of a Suspension Bridge

    Anchor Block: Just looking at the figure we can compare it as a dead man
    having no function of its own other than its weight.

    Suspension girder: It is a girder built into a suspension bridge to distribute the


    loads uniformly among the suspenders and thus to reduce the local
    deflections under concentrated loads.

    Suspenders: a vertical hanger in a suspension bridge by which the road is


    carried on the cables

    Tower: Towers transfers compression forces to the foundation through piers.

    Saddles: A steel block over the towers of a suspension bridge which acts as a
    bearing surface for the cable passing over it.

    Cables: Members that take tensile forces and transmit it through saddles to
    towers and rest of the forces to anchorage block.

    TYPES OF SUSPENSION BRIDGES


    Number of Spans

    Continuity of Stiffening Girders

    Types of Suspenders

    Types of Cable Anchoring

    Main Towers

    CABLES

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