What Kind of Bridge?

Important Words Span: 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 Words Compression: 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 Bridge A rigid horizontal structure that is resting on two piers, one on each side. Load Compression Tension Compression Reaction Force Reaction Force

Beam Bridge Typical 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://wikipedia.com http://brasiliabsb.com/tabfotos.htm

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 (over water & land): Jiaozhou Bay Bridge in China – 42.5 km (about 26 miles) long (longest span 260 m) 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)

Cantilever Bridge Cantilever 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 Bridge Typical Span Lengths: 40m - 500m World's Longest: Pont de Quebec Total Length: 863m Center Span: 549m www.sepaq.com/Photos/J380/batPontQuebecC.jpg

Firth of Forth Bridge Under Construction (1890) http://www.rsgs.org/ifa/gems/bridgegap.html http://www.nas.gov.uk/about/071004.asp

Firth of Forth Bridge - Scotland http://www.edinburgh-scotland.net/images/ForthBridge11L.jpg

Basic Spans http://www.slideshare.net/illpa/bridge-1403689

Truss Supporting 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 Compression tension Reaction force http://www.britannica.com/EBchecked/topic/79272/bridge

Arch Bridge An 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 Bridge Typical Span Lengths: 40m – 150m (can be 500m +) World's Longest: Chaotianmen Bridge, Chongqing, China Total Length: 1741 m Center Span: 552 m http://mainbridge.co.cc/?p=74

Arch Bridge USA’s Longest: New River Gorge Bridge, U.S.A. Total Length: 924m Center Span: 518m http://cs101.wvu.edu/wvscenes http://www.post-gazette.com/pg/06251/719452-37.stm

Suspension Bridge The 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. Compression Load Anchorage Tension Reaction Force http://www.brantacan.co.uk/starterpages.htm

Suspension Typical Span Lengths: 70m - 1,000m+ (can be close to 2000 m) World's Longest: Akashi Kaikyo Bridge, Japan Total Length: 3,911m Center 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 1964 2. 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 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. 1960 10. Walt Whitman Delaware River at Philadelphia 2,000 http://www.infoplease.com/toptens/

Cable Stayed Bridge A 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. Tension Load Compression Reaction Force http://www.brantacan.co.uk/starterpages.htm

Cable Stayed Typical Span Lengths: 110m - 480m (can be 1000m +) World's Longest: Russky Bridge, Russia Total Length: 3,100 m Center Span: 1,104 m www.veooz.com 

Every 100 ft = about 30.5 m 45 - 137 m 122 - 366 m 229 - 610 m 152 – 914+ m http://trimet.org/pdfs/pm/general_docs/HNTB_July15_Low_Res.pdf

Summary of Forces on Bridges

Summary of Forces on Bridges