what kind of bridge?. important words span: the distance between two bridge supports (column, tower,...
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What Kind of Bridge?
Important WordsSpan: the distance between two bridge
supports (column, tower, canyon walls…)Abutment: a. The part of a structure that
bears the weight or pressure of an arch.
b. A structure that supports the end of a bridge.c. A structure that anchors the
cables of a suspension bridge.Girder: a beam, made of steel, wood, or
reinforced concrete, used as a main horizontal support in a building or bridge – can be a box girder or truss girder
Girders
http://www.fhwa.dot.gov/bridge/steel/pubs/if12052/volume05.pdf
More Important WordsCompression: a force that compresses or
shortens the thing it is acting on. Pushing together force.
Tension: a force that expands or lengthens the thing it is acting on. Pulling apart force.
http://www.howstuffworks.com/bridge.htm
Beam BridgeA rigid horizontal structure that is resting on two piers, one on each side.
LoadCompression
Tension
Reaction Force Reaction ForceCompression
Beam BridgeTypical Span Lengths: 10m - 200m (can be up to 300m +)World's Longest: Shipanpo Bridge, China (restressed Concrete Girder)
Center Span: 330m
Ponte Costa e Silva (Rio-Niteroi Bridge), Brazil (Steel Box/Plate Girder)
Center Span: 300m
http://brasiliabsb.com/tabfotos.htm
http://wikipedia.com
Continuous Span Beam Bridge
Several Beam Bridges linked together
World’s Longest (over water): Lake Ponchartrain Bridge in Louisiana – 38.4 km (nearly 24 miles) long
http://worldslongestbridges.blogspot.com/2009/12/worlds-longest-bridges.html
More Continuous Span
World’s Longest (high speed railroad): Danyang – Kunshan Grand Bridge between Beijing and Shanghai – 164.8 km (about 120 miles) long (longest span 80 meters)
World’s Longest (over water & land): Jiaozhou Bay Bridge in China – 42.5 km (about 26 miles) long (longest span 260 m)
Cantilever BridgeCantilever bridges are a modified form of beam bridge, with the support being placed not at the end, but somewhere in the middle of the span. A cantilever is a structure or beam that is unsupported at one end but supported at the other, like diving boards.
Queensboro (59th St) Bridge over the East River
http://www.richmangalleries.com/cantilever_bridges.htm
Cantilever Bridge
Cantilever BridgeTypical Span Lengths: 40m - 500mWorld's Longest: Pont de QuebecTotal Length: 863mCenter Span: 549m
www.sepaq.com/Photos/J380/batPontQuebecC.jpg
Firth of Forth Bridge Under Construction
(1890)
http://www.nas.gov.uk/about/071004.asphttp://www.rsgs.org/ifa/gems/bridgegap.html
Firth of Forth Bridge - Scotland
http://www.edinburgh-scotland.net/images/ForthBridge11L.jpg
Basic Spans
http://www.slideshare.net/illpa/bridge-1403689
TrussSupporting structure - lattice work added to many types of bridges. Trusses are skeletal structures made up of many small beams (normally in the shape of triangles). As the size of a beam bridge increases, so must the size of the truss
Forces in a Bridge with Trusses
load
tension
Compression
Reaction force
http://www.britannica.com/EBchecked/topic/79272/bridge
Arch BridgeAn arch bridge is a semicircular structure with abutments on each end. The arch naturally brings the weight (a force) of the load from the roadway to the abutments. Used by the ancient Romans. Can be made out of brick or stone.
Load
Compression
Reaction Force
http://www.matsuo-bridge.co.jp/english/bridges/index.shtm
Arch BridgeTypical Span Lengths: 40m – 150m (can be 500m +)World's Longest: Chaotianmen Bridge, Chongqing, ChinaTotal Length: 1741 mCenter Span: 552 m http://mainbridge.co.cc/?p=74
Arch BridgeUSA’s Longest: New River Gorge Bridge, U.S.A. Total Length: 924mCenter Span: 518m
http://cs101.wvu.edu/wvscenes
http://www.post-gazette.com/pg/06251/719452-37.stm
Suspension BridgeThe deck of the bridge is held up by cables. main cables strung over two towers and anchored
on either end vertical (or hanging) cables connect to the main
cables and connect to the road (called suspenders)
towers support most of the road deck’s weight.
http://www.brantacan.co.uk/starterpages.htm
Tension LoadCompression
Reaction Force
Anchorage
Suspension
Typical Span Lengths: 70m - 1,000m+ (can be close to 2000 m)
World's Longest: Akashi Kaikyo Bridge, Japan
Total Length: 3,911mCenter Span: 1,991m
www.bergen.org/.../2002/wp_bridge/akashi.jpg
Longest U.S. Suspension Bridges
Rank Name Location Feet Completed
1. Verrazano-Narrows Lower New York Bay 4,260 19642. Golden Gate San Francisco Bay 4,200 1937
3. Mackinac Mackinac Straits, Mich. 3,800 1957
4. George Washington Hudson River at New York City
3,500 1931
5. Tacoma Narrows II Puget Sound at Tacoma, Wash.
2,800 1950
6. San Francisco–Oakland Bay
San Francisco Bay 2,310 1936
7. Bronx–Whitestone East River, New York City 2,300 1939
8. Delaware Memorial Delaware River near Wilmington, Del.
2,150 1951, 1968
9. Seaway Skyway St. Lawrence River at Ogdensburg, N.Y.
2,150 1960
10. Walt Whitman Delaware River at Philadelphia
2,000 1957http://www.infoplease.com/toptens/
Cable Stayed BridgeA continuous beam with one or more towers built above piers. From these towers, cables stretch down diagonally (usually to both sides) and attach to the girder to support the bridge deck.
LoadTension
Reaction Force
http://www.brantacan.co.uk/starterpages.htm
Compression
Cable StayedTypical Span Lengths: 110m - 480m (can be 1000m +)World's Longest: Russky Bridge, RussiaTotal Length: 3,100 mCenter Span: 1,104 m www.veooz.com
http://trimet.org/pdfs/pm/general_docs/HNTB_July15_Low_Res.pdf
122 - 366 m
45 - 137 m
229 - 610 m
152 – 914+ m
Every 100 ft = about 30.5 m
Summary of Forces on Bridges
Summary of Forces on Bridges
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