Tag Archive for Tag: Bridges

Tag: Bridges Erection of Cable-Suspended Bridges

The ease of erection of suspension bridges is a major factor in their use for long spans. Once the main cables are in position, they furnish a stable working base or platform from which the deck and stiffening truss sections can be raised from floating barges or other equipment below, without the need for auxiliary falsework. For the Severn Bridge, for example, 60-ft box-girder

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Tag: Bridges 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: Bridges Classification of Bridges by Span

Bridges have been categorized in many ways. They have been categorized by their principal use as highway, railroad, pedestrian, pipeline, etc.; by the material used in their construction as stone, timber, wrought iron, steel, concrete, and prestressed concrete; by their structural form as girder, box-girder, moveable, truss, arch, suspension, and cable-stayed; by structural behavior as simple span, continuous, and cantilever; and by their

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Tag: Bridges Classification and Characteristics of Cable-Stayed Bridges

The cable-stayed bridge has come into wide use since the 1950s for medium- and long-span bridges, because of its economy, stiffness, esthetic qualities, and ease of erection without falsework. Cable-stayed bridges utilize taut cables connecting pylons to a span to provide intermediate support for the span. This principle has been understood by bridge engineers for at least two centuries, as indicated in Art. 15.1.

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Tag: Bridges Evolution of Cable-Suspended Bridges

Early cable-suspended bridges were footbridges consisting of cables formed from twisted vines or hide drawn tightly to reduce sag. The cable ends were attached to trees or other permanent objects located on the banks of rivers or at the edges of gorges or other natural obstructions to travel. The deck, probably of rough-hewn plank, was laid directly on the cable. This type of construction

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Tag: Bridges Examples of Arch Bridges

Thanks to the cooperation of several engineers in private and public practice, detailed information on about 25 arch bridges has been made available. Sixteen have been selected from this group to illustrate the variety of arch types and forms in the wide range and span length for which steel arches have been used. Many of these bridges have been awarded prizes in the annual

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Tag: Bridges Characteristics of Curved Girder Bridges

Past practice in design of new highways often located bridges first, then aligned the roadway with them. Current practice, in contrast, usually fits bridges into the desired highway alignment. Since curved crossings are sometimes unavoidable, and curved ramps at interchanges often must span other highways, railroads, or structures, bridges in those cases must be curved. Plate or box girders usually are the most

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Tag: Bridges Basic Allowable Stresses for Bridges

Table 11.16 lists the basic allowable stresses for highway bridges recommended in AASHTO  ‘‘Standard Specifications for Highway Bridges’’ for ASD. The stresses are related to the minimum yield strength Fy , ksi, or minimum tensile strength Fu, ksi, of the material in all cases except those for which stresses are independent of the grade of steel being used. The basic stresses may

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