Case Study of the Longest Suspension Bridge in the world - The Akashi Kaikyo Bridge. In this presentation, various structural features of this bridge are discussed and a few videos provided helps us to get a better understanding of it.

1. COMMUNICATIONS
INDIAN INSTITUTE OF TECNOLOGY, ROORKEE
AUTUMN SEMESTER:- 2016-17
BY:- ADARSH (14113004)
CIVIL ENGINEERING(3rd yr)

2. THE AKASHI KAIKYŌ BRIDGE
THE LONGEST SUSPENSION BRIDGE IN THE WORLD
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3. INTRODUCTION
• Situated in Japan, designed by Satoshi
Kashima.
• Built over the Akashi Strait, links the city of
Kobe on Japanese mainland to Iwaya on Awaji
island.
• Construction period:- 1988-1998.
• Construction company:- MATSUO BRIDGE CO.
• Original plan:- contained railway lines, about to
be cancelled by the government.
• 1985 – Decision taken to built only road bridge;
construction started in 1988.
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4. FEATURES
• 3 records:- Longest suspension bridge(1991 m
central span), highest towers in a suspension
bridge(297 m), most expensive bridge ever
built(500 billion yen).
• 2 million workers involved in the construction.
• Carries 6 lanes of roadway.
• Annual revenue of 19 billion yen from toll.
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5. STRUCTURAL FEATURES
1. Materials
2. The Suspension Bridge
3. Stronger Cables
4. Building underwater
5. Taller towers
6. Wind resistant
7. Earthquake resistant
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6. MATERIALS
• First steel bridge:- IRONBRIDGE (30 m).
• Need for lighter components
• Major component used is steel.
• Use of pre-fabricated steel shapes:-
both in towers and the deck.
• Contains 250,000 tonnes of steel.
• Advanced technology to take care of
rusting.
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7. THE SUSPENSION BRIDGE
• First suspension bridge:- Menai Strait Bridge(177 m).
• Concept used :- Anchorage of cables.
• Construction of foundation.
• 2 Big holes dug into the ground.
• Each filled with around 230,000 cu. m. of concrete.
• Metal frames added for anchorage.
• Casting of concrete on these metal frames.
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10. STRONGER CABLES
• Weight of each main cable:- 25,000 tonnes.
• 36,830 wires in one cable.
• Diameter :- 112 cm.
• Strand length:- 4070 m(approx.)
• Enough wires to circle the earth 7 times.
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11. BUILDING UNDERWATER
• Use of caisson, made of steel.
• Dimensions of caisson:- dia-80 m, height-70 m.
• First – sink it into the water upto the bed.
• Second – fill it with concrete.
• Can be done manually or mechanically.
• Use of super-concrete in the foundation.
• Speciality :- hardening under seawater.
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13. TALLER TOWERS
• Height of tower:- 297 m
• Cruciform cross-section :- increased stability.
• Comprised of 30 steel sections.
• Connections done by
Advanced robot welding
1.5 million bolts.
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15. • Triangular stiffening steel girders.
• Lighter in weight as compared to steel boxes.
• Complete passage of wind.
• Testing in one of the largest wind tunnels.
• Length of prototype :- 40 m.
• Tested against a wind speed of 300 km/hr.
• Suggested to deflect the wind and also stiffen
against it.
• Mesh provided in the centre of roadway and a
huge beam below the roadway
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WIND RESISTANT

17. EARTHQUAKE RESISTANT
• Testing of dampers by man made quake.
• 1995 earthquake.
• Increased the length by a metre.
• Capable of resisting 8.5 magnitude earthquake.
• Use of 20 Tuned Mass Dampers(TMD).
• Reduces the deflection in the towers.
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19. SOME CLASSIC EXAMPLES
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Verrazano Narrows
Bridge
Golden Gate Bridge
Brooklyn Bridge

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