Bridges Design Engineering CAMS South Some Uses of
Bridges Design & Engineering CAMS South
Some Uses of Bridges n n n Walkways Highways/Roads Railways Pipelines Connecting lands Crossing rivers and canyons
Types of Bridges n Arch n Truss n Cantilever n Cable-Stayed n Beam n Suspension
What makes a bridge stay up? n Forces n n n Compression – a pushing or squeezing force Tension – a pulling or stretching force Load – the weight a structure must support Dead Load – weight of the structure Live Load – additional weight such as cars, people, snow, wind, etc.
BEAM BRIDGE §BEAM BRIDGE - A bridge built of beams whose ends rest on piers or abutments. §BEAM - A horizontal structure member supporting vertical loads by resisting bending. §PIER - A vertical structure that supports the ends of a beam. §SPAN - The horizontal space between two supports of a structure.
I 81 and Rt 30 Chambersburg, PA
Lake Pontchartrain Causeway 23. 83 Miles Long
Truss Bridges §Truss – a rigid frame composed of short, straight pieces joined to form a series of triangles or other stable shapes §Many variations of truss bridge designs
Truss Bridge Definitions Road Bed – Roadway portion of bridge, sometimes called “Deck” n Superstructure – Consists of all bridge components including and above the road bed or deck n Substructure – Consists of all bridge components below the road bed or deck n
Martin’s Mill Bridge Greencastle, PA Truss Bridge Town Lattice Truss Design
Walnut St Bridge Harrisburg, PA
Arch Bridges n n n Arch Bridge - A bridge whose main support structure is an arch Arch – Curved structural member spanning an opening and serving as a support Bridge Abutments – The structures that support the ends of the bridge
Arch Bridges Works by Compression n
Arch Bridges Durable bridge form - Many old stone arch bridges are still standing today. n Can be constructed with many materials stone, wood, steel, concrete n Have you seen these bridges? n
Burnside Bridge, Antietam Battlefield, Sharpsburg, MD
I 70 South Mountain
New River Gorge Bridge, West Virginia
Suspension Bridges n A bridge which carries its deck with many tension members attached to cables draped over tower piers.
Suspension Bridges Can clear span great distances. n Beautiful design and many are iconic. n Extremely efficient in terms of materials n Most expensive type of bridge to construct. n World Record span between towers: Akashi Kaikyō Bridge 6532 feet main span n Have you seen these bridges? n
Suspension Bridges n Works by Tension and Compression
Golden Gate Bridge, San Francisco, CA
Brooklyn Bridge, Brooklyn, NY
Chesapeake Bay Bridge, Annapolis, Maryland
Verrazano-Narrows Bridge, New York, NY Longest main span in United States 4260 feet
Akashi Kaikyō Bridge, Japan 6532 feet main span
Tacoma Narrows Bridge Failure Video
Cable-Stayed Bridges A variation of suspension bridge in which the tension members extend from one or more towers at varying angles to carry the deck. n Less expensive and faster to construct compared to a suspension bridge. n Relatively new form of bridge. n
Cable-Stayed Bridges n n n Piers – the vertical supporting structures Cables – thick steel ropes from which the decking is suspended Decking – the supported roadway on a bridge
Cable-Stayed Bridges n Works by Tension AND Compression
Zakim Bridge, Boston, MA
Sunshine Skyway Bridge, Tampa, FL
Sundial Bridge, Redding, CA
Cantilever Bridges §A structural member that projects beyond a supporting column or wall and is counterbalanced and/or supported at only one end. Cantilever Firth of Forth-Forth Rail Bridge, Edinburgh, Scotland
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