Suspension BridgesSuspension Bridges

Getting ready to design your Getting ready to design your own!own!

What is a suspension bridge:What is a suspension bridge:

One of the several types of bridge designsOne of the several types of bridge designs

Used for the longest spansUsed for the longest spans

Cables-Cables- suspend the roadway suspend the roadway

Towers-Towers- stabilize wire cables stabilize wire cables (offer little support)(offer little support)

Anchorages-Anchorages- key to the structure, mass that keeps key to the structure, mass that keeps cables tight, gives the bridge structure cables tight, gives the bridge structure

Suspension Bridge

With anchorages

Without anchorages

Roebling’s Engineering Roebling’s Engineering Contributions:Contributions:

Engineer famous for American suspension bridgesEngineer famous for American suspension bridges

Use of steelUse of steel

Development of wire cablesDevelopment of wire cables SpinningSpinning: assembling heavy cables in the air: assembling heavy cables in the air

Advancement of stiffening trussesAdvancement of stiffening trusses TrussTruss: triangular structure that adds strength not weight: triangular structure that adds strength not weight

Roebling’s First Bridge:Roebling’s First Bridge: Niagara Falls in 1855 to Niagara Falls in 1855 to 18971897

825 feet 825 feet Suspension railwaySuspension railway

Roebling’s Brooklyn Bridge:Roebling’s Brooklyn Bridge:

Longest of it’s time Longest of it’s time 1595 feet in 18831595 feet in 1883

Other Famous Other Famous Suspension Suspension

BridgesBridges

Akashi Kaikyo BridgeAkashi Kaikyo Bridge• Hyogo, Japan Hyogo, Japan • 6,529 ft 6,529 ft • Longest suspension Longest suspension

bridge todaybridge today

Top 10 bridges in the world by length:

1. Akashi-Kaikyo Bridge (Japan), 1991 m — 1998

2. Xihoumen Bridge (China), 1650 m — 2007 3. Great Belt Bridge (Denmark), 1624 m — 1998 4. Runyang Bridge (China), 1490 m — 2005 5. Humber Bridge (England, United Kingdom), 1410 m — 1981.

(The longest span from 1981 until 1998.)6. Jiangyin Suspension Bridge (China), 1385 m — 1997 7. Tsing Ma Bridge (Hong Kong, China), 1377 m — 1997 (longest

span with both road and metro)8. Verrazano-Narrows Bridge (USA), 1298 m — 1964. (The longest

span from 1964 until 1981.) 9. Golden Gate Bridge (USA), 1280 m — 1937. (The longest span from

1937 until 1964.) 10.Yangluo Bridge (China), 1280 m — 2007

• Brooklyn Bridge ( NY,USA, 1883), The first steel-wire suspension bridge. • Bear Mountain Bridge (NY, USA, 1924), The longest span (497 m)from 1924

to 1926. The first suspension bridge to have a concrete deck. The construction methods pioneered in building it would make possible several much larger projects to follow.

• John A. Roebling Suspension Bridge (Ohio, USA: 1866), Then the longest wire suspension bridge in the world at 1,057 feet (322 m) main span.

• Mackinac Bridge (USA, 1957), The longest suspension bridge between anchorages in the Western hemisphere.

• Roebling's Delaware Aqueduct (NY,USA, 1847) The oldest wire suspension bridge still in service in United States.

• Royal Gorge Bridge (Colorado, USA, 1929), The highest (384 m) suspension bridge in the world.

• San Francisco – Oakland Bay Bridge (USA, 1936), Until recently, this was the longest steel high-level bridge in the world. The oldest in the world still in use today.

Bridges close to home!Bridges close to home!

Mackinac Island Mackinac Island BridgeBridge

•The longest between anchorages in the Western hemishere

Total length: 26,372 feet (8,038 m)

Width: 68.6 feet (20.9 m)

Height: 522 feet (159 m)

Longest span: 3,800 feet (1,158 m)

Even closer to home…

Ambassador Bridge

Detroit

•Total length7,500 feet (2,286 m)•Longest span1,850 feet (564 m)

Ambassador Bridge Dimensions:

A

BC

Total length ______________________ (A)

Span length (tower to tower) _____________________(B)

Total height of each tower _________________________(C)

Total width of the roadway __________________________

The General Contractor wants to see a scale model of this bridge before you begin construction. You will have limited workspace. You will need to scale the feet down to a workable unit. In this case you will use 1 inch to equal 50ft.

• Total scale length:

• Scale span length:

• Total scale height:

• Total scale roadway width: