AKASHI KAIKYO BRIDGE Everest Education Society Group of Institutions College of Engineering and Technology, Aurangabad (Maharashtra) Department of Civil Engineering AKASHI KAIKYO BRIDGE PRESENTED BY SHEIKH MOHSIN NAZEER UNDER THE GUIDANCE OF PROF. SYED MONA ALI

1. INTRODUCTION 2. HISTORY 3. TIMELINE 4 1.INTRODUCTION 2.HISTORY 3.TIMELINE 4.REASONS TO BUILD THIS BRIDGE 5.ARTITECTURE 6.DIFFICULTIES FACE BEFORE CONSTRUCTION 7.CONCEPT 8.CONSTRUCTION 9.A NEAR ESCAPE? 10.NEW TECHNIQUES DEVELOPED FOR AKASHI KAIKYO BRIDGE 11.CONCLUSION 12.REFERENCES

1.INTRODUCTION 3. At a cost of $4.3 billion, it was the most expensive bridge project.

AKASHI KAIKYO BRIDGE

2.HISTORY Before the Akashi Kaikyo Bridge was built, ferries carried passengers across the Akashi Strait in Japan. This dangerous waterway often experiences severe storms, and in 1955, two ferries sank in the strait during a storm, killing 168 children. The ensuing shock and public outrage convinced the Japanese government to develop plans for a suspension bridge to cross the strait. The original plan called for a mixed railway-road bridge, but when construction on the bridge began in April 1986, the construction was restricted to road only, with six lanes. Actual construction did not begin until May 1986, and the bridge was opened for traffic on April 5, 1998. The Akashi Strait is an international waterway that necessitated the provision of a 1,500m wide shipping lane.

3. TIMELINE 1998 - Opened for traffic.

4.REASONS TO BUILD THIS BRIDGE 3. An exercise of this magnitude had not yet been attempted. This was a symbol for Japan’s prosperity

5. ARCHITECTURE The bridge has three spans. The central span is 1,991 m (6,532 ft), and the two other sections are each 960 m (3,150 ft). The bridge is 3,911 m (12,831 ft) long overall. The central span was originally only 1,990 m (6,529 ft), but the Kobe earthquake on January 17, 1995, moved the two towers sufficiently (only the towers had been erected at the time) so that it had to be increased by 1 m (3.3 ft). The bridge was designed with a two- hinged stiffening girder system, allowing the structure to withstand winds of 286 kilometres per hour (178 mph), earthquakes measuring to 8.5 on the Richter scale, and harsh sea currents. The bridge also contains pendulums that are designed to operate at the resonance frequency of the bridge to damp forces. The two main supporting towers rise 298 m (978 ft) above sea level, and the bridge can expand because of heating up to 2 metres (7 ft) over the course of a day.

6. DIFFICULTIES FACED BEFORE CONSTRUCTION · The proposed bridge had to have a length of almost 4 km, a distance that had not yet been attempted.

7. CONCEPT The function of this bridge was to support the traffic load coming on the 6-lane freeway. But before that the bridge had to carry its own self weight. The load coming on the bridge was distributed as 91% to support its own weight and only the remaining 9% was for traffic load. The basic concept consisted of erecting two towers and passing steel cables through it. The girder was connected to the cable by means of hangar cables.

8. CONSTRUCTION The construction phase was divided into 4 stages:- Stage 1:- Construction of tower foundation Stage 2:- Construction of towers Stage 3:- Fixing of steel cables to towers. Stage 4:- Placing the roadway

9. A NEAR ESCAPE? · After the earthquake, detailed surveying showed that the tower on the Awaji side had shifted a meter apart due to the quake. It could have been more dangerous than this.

10. NEW TECHNIQUES DEVELOPED FOR AKASHI KAIKYO BRIDGE 3. Super-strength steel wire was developed for the cable by changing the alloy proportions. This super-strength cable was so strong that a 5mm thick wire could carry 3 family cars

11. CONCLUSION We know that the Akashi Kaikyo Bridge is located at a place where weather and sea is very rough and it is in an earthquake zone. Still the determination and dedication of the Japanese engineers was instrumental in gifting this marvel. The Akashi Kaikyo Bridge has been set as a benchmark for future bridge constructions. The Mazena Bridge in Italy will soon overtake Akashi Kaikyo as the world’s longest bridge. With the advent of carbon fibre, it may be used in cables and if this being the case, longer bridges can be constructed. Normally as the span increases the length of the cable increases and this leads to an increase in the load to be carried by the bridge. But if carbon fibre is used, it will be lighter than steel and stronger leading to huger spans

12. REFERENCES 3. James Hill, Rola Idriss (2006), Bridge Construction, Committee on construction of bridges and structures