Tag Archive for Tag: Bridge

Tag: Bridge Aerodynamic Analysis of Cable-Suspended Bridges

The wind-induced failure on November 7, 1940, of the Tacoma Narrows Bridge in the state of Washington shocked the engineering profession. Many were surprised to learn that failure of bridges as a result of wind action was not unprecedented. During the slightly more than  12 decades prior to the Tacoma Narrows failure, 10 other bridges were severely damaged or destroyed by wind action

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Tag: Bridge Cable-Stayed Bridge Analysis

The static behavior of a cable-stayed girder can best be gaged from the simple, two-span example of Fig. 15.54. The girder is supported by one stay cable in each span, at E and F, and the pylon is fixed to the girder at the center support B. The static system has two internal cable redundants and one external support redundant. If the cable

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Tag: Bridge Erection of Arch Bridges

Erection conditions vary so widely that it is not possible to cover many in a way that is generally applicable to a specific structure. Cantilever Erection. For arch bridges, except short spans, cantilever erection usually is used. This may require use of two or more temporary piers. Under some conditions, such as an arch over a deep valley where temporary piers are very

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Tag: Bridge Comparison of Arch with Other Bridge Types

Because of the wide range of span length within which arch construction may be used (Art. 14.3), it is competitive with almost all other types of structures. Comparison with Simple Spans. Simple-span girder or truss construction normally falls within the range of the shortest spans used up to a maximum of about 800 ft. Either true arches under favorable conditions or tied arches

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Tag: Bridge Skewed Bridges

To reduce scour and to avoid impeding stream flow, it is generally desirable to orient piers with centerlines parallel to direction of flow; therefore skewed spans may be required. Truss construction does not lend itself to bridges where piers are not at right angles to the superstructure (skew crossings). Hence, these should be avoided and this can generally be done by using longer spans

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Tag: Bridge Bridge Layout

Trusses, offering relatively large depth, open-web construction, and members subjected primarily to axial stress, provide large carrying capacity for comparatively small amounts of steel. For maximum economy in truss design, the area of metal furnished for members should be varied as often as required by the loads. To accomplish this, designers usually have to specify built-up sections that require considerable fabrication, which tend to

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Tag: Bridge Continuous-Beam Bridges

Articles 12.1 and 12.3 recommended use of continuity for multispan bridges. Advantages over simply supported spans include less weight, greater stiffness, smaller deflections, and fewer bearings and expansion joints. Disadvantages include more complex fabrication and erection and often the costs of additional field splices. Continuous structures also offer greater overload capacity. Failure does not necessarily occur if overloads cause yielding at one point in

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Tag: Bridge Composite Box-Girder Bridges

Box girders have several favorable characteristics that make their use desirable for spans of about 120 ft and up. Structural steel is employed at high efficiency, because a high percentage can be placed in wide flanges where the metal is very effective in resisting bending. Corrosion resistance is higher than in plate-girder and rolled-beam bridges. For, with more than half the steel surface

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Tag: Bridge Through Plate-Girder Bridges with Floorbeams

For long or heavily loaded bridge spans, restrictions on depth of structural system imposed by vertical clearances under a bridge generally favor use of through construction. Through girders support the deck near their bottom flange. Such spans preferably should contain only two main girders, with the railway or roadway between them (Fig. 12.46). In contrast, deck girders support the deck on the top flange

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Tag: Bridge Characteristics of Beam Bridges

Rolled wide-flange shapes generally are the most economical type of construction for shortspan bridges. The beams usually are used as stringers, set, at regular intervals, parallel to the direction of traffic, between piers or abutments (Fig. 12.1). A concrete deck, cast on the top flange, provides lateral support against buckling. Diaphragms between the beams offer additional bracing and also distribute loads laterally to the

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