Akashi-Kaikyo Bridge, Study

Akashi-Kaikyo Bridge, Study

INTRODUCTION

In this present monographic work, whose content will lead us to know one of the mega structures that was represented a challenge for engineering such as the Akashi Kaikyo bridge which is located in Japan.

The four phases of the construction of the Akashi Kaikyo bridge will be explained in detail .This bridge is the longest and most expensive in the world than the city of Kobe with the island of Awaji-sh.This bridge caused a great impact on the economic and cultural field.

The Akashi Kaikyo bridge presented many inconveniences during its construction process such as typhoons and earthquakes, for that reason many thought it could not be built, however modern engineering shows us that there is nothing impossible.

Yo. DESCRIPTION:

(The Akashi-Kaikyo bridge represents an engineering milestone): “The Akashi Kaikyo bridge (known as the Pearl bridge) located in Japan is the longest section of section of section that has been built;It has a height of 280 meters with a final length of 3.911 meters, costing more than three billion dollars. Initial this bridge was proposed for both road traffic and the railway. In 1985, the rail alternative was abandoned and was restricted only for highway use, which would be formed by six lanes."

Therefore, it is highlighted that there were modifications since the first planes of the bridge contained rail lines which was canceled by the Government and its use was limited only for highway.

For their design, climatic conditions such as hurricane winds, hurricanes and tsunamis were taken into account.

(The Akashi-Kaikyo bridge represents an engineering milestone): “To carry out this magnificent structure, more than 2 million workers, billions of euros, 181 thousand tons of steel and 1.4 million cubic meters of concrete. Those responsible for executing this megaproject were the architect and engineer Satoshi Kashim.The promoter of this project was Honshu Shikoku Bridge."

The Akashi-Kakyo bridge has three records: longest suspension bridge (3.911m), higher bridge (282.80m-297.30m) and the most expensive bridge ever built (500 million yens).

II. DESIGN:

(The Akashi-Kaikyo bridge represents an engineering mileaccording to the surrounding and balanced environment between the shadow and the light .The anchors were designed to make the huge concrete structures seem small and balanced."

The design of the akashi bridge –kakyo was based on the impact it would have on the environment. That is why to paint the bridge they used the greenish gray color, that color was chosen because it is a vivid and at the same time soft color that harmonizes with an urban landscape. So that much maintenance is no longer required, a final fluopolimero paint layer was put to prevent corrosion and maintain shine.

III. BUILDING:

(The Akashi-Kaikyo bridge represents an engineering mileThe strength to have the bridge will be the one that serves to endure the load of traffic."

Because of this for the construction of the Akashi – Kaikyo bridge, both the cables and the road had to be more resistant at the same time very light. The weight of the megaestructure is distributed as follows:

• Cables (57.700tn)
• Beams (89.200tn)
• Torre (46.200tn)

IV. STRUCTURE:

(The Akashi-Kakyo bridge represents an engineering mile."

Because Japan has one of the worst climatic conditions they placed the bridge board (it is the traffic surface) on a support armor formed by a complex network of triangular supports below the road.

Kobe’s earthquake caused some damage to the structure such as the central section increase 80 cm reaching approximately 1991 meters, the southern side increase 30cm increase .So the total length of the bridge increases 110cm.

V. Construction phases:

Yo. FIRST PHASE:

• Anchors:

(Analysis and Design of Coasts Bridges, 2007): “Anchor chambers serve to fix cables to the ground, normally resisting by gravity the horizontal forces that transmit these cables."

First to start the construction of the bridge, giant anchor points had to build from which the cables will be fixed .One of the anchors would be placed in Kobe and the other in Awaji, but only the anchor could be placed in Awaji while the rest of the work was built on sediments. For the north anchor, approximately 60 meters were thus creating containment walls, which proceeded to fill it with concrete by layers;This whole process ended in 3 months;Then the steel reinforcement was placed, which provides the connection points for the anchor tower. For the southern anchor only 18metters and was on a granite floor.

• Foundations:

(The Akashi-Kakyo bridge represents an engineering milestone): “The main elements used in deep foundations are: piles and screens."

On the Akashi-Kaikyo bridge, the element used was the prismatic pile that was concreted at its base and was installed by means of the squad for which the river mud had to be removed and then the foundations begin to be placed.

(The Akashi-Kaikyo bridge represents an engineering mileThey sink by the same weight, the process is repeated and the foundations are raised from the shores in different phases."

In this phase of the foundations is where a problem occurs since the previously mentioned method does not meet on the bridge since it has a depth of 110 meters greater than the common bridges and for having aggressive currents, so they used another method.

(The Akashi-Kaikyo bridge represents an engineering mile."

For the Akashi bridge –kaIikyo made steel hollow molds each weighing 15.000 tons .To get the steel molds sinking 32 pumps, for which it took approximately eight hours .To culminate the foundations, they should be filled with concrete, but normal concrete is quickly dissolved by being in contact with water, which designed a special concrete that maintains cohesion with water.Approximately 265 cubic meters are filled.

II. SECOND STAGE:

• Towers:

(The Akashi-Kakyo bridge represents an engineering mileor other climatic conditions of the place."

The Akashi bridge –kaIikyo were built with approximately 1 steel plates.5 million screws since that way is lighter and more flexible.The two main towers have a height of 283 meters above the pillars.The two towers raised piece by piece at a height of 297 meters from sea level .This process of 18 months .The bridge can expand through the heat approximately two meters in one day.

• Shock absorbers:

Because Japan is a turbulent zone with very aggressive sea currents and very strong winds 20 shock absorbers were placed each of 10 tons, these shock absorbers oscillate in the opposite direction to that of the wind .On the bridge, two hinges reinforcement beams were placed that allows the winds of 290km/hour, earthquakes and marine current to resist .

III. THIRD PHASE:

• Cables:

(ANALYSIS AND DESIGN OF POST BRIDGES, 2007) Cables are the most important elements to resist external loads in the structure of a suspension bridge. The cable can present various configurations, but all of them are based on the use of thin -resistance wires.

(The Akashi-Kakyo bridge represents an engineering mileThe same tension and as an original curvature of the coil is canceled."

(The longest section of the past millennium and the present, 2002) mentions that: "The PPWS technique is applied to the Akashi bridge and in some other hanging bridges of long stretch in Japan (for example: Minami, Kurushima,Kita), and also in China (for example: Jiangyin, Xiling, Boca Tigris-1, presumably also Runyang, but not tsing ma). Those countries have the necessary factories for this technique."

The Akashi –kayyo Bridge has two main cables, for which 300 thousand kilometers of cable was needed .For the wiring to be very resistant, the composition of the steel adding silicone and alloys had to be modified .Each main cable has 37 thousand wire strands with a diameter of 1122 millimeters .The Akashi bridge wires –kakyo have a last tension resistance of 1800 MPA.The wire they used was 10mm Poly-Aramid fiber which was protected against corrosion

IV. FOURTH PHASE:

• b) Boards and beams:

On the Akashi –kayyo bridge, a jealousy table was used that will provide rigidity to the bridge .For the road platform, a vassy beam was chosen. The steel beams had the following dimensions: Width (35.5m) and a depth of (14m).Each 100 -ton steel section formed the 6 -lane road and four kilometers of narrow. 15 months were delayed in placing the sections of the beams per final.

SAW. Conclusions:

• The construction of the Akashi –kayyo bridge was a challenge for engineers to understand and solve problems in the execution process.
• Thanks to the construction of the Akashi bridge –kakyo were able to design another type of concrete that maintains their cohesion in the water.
• Thanks to the construction of the Akashi bridge –kakyo put into practice a new wiring method that is executed aerially.
• A new method for the placement of foundations was used, in suspension bridges that consists of the prefabrication of steel molds in dry dikes, and then submerged by filling them with seawater.