Megastructures - Kansai International Airport - Japan

Kansai International Airport is an international airport located on an artificial island in the middle of Osaka Bay, off the shore of the cities of Sennan and Izumisano and the town of Tajiri in Osaka Prefecture, Japan. (It should not be confused with Osaka International Airport, which is closer to the city and now handles only domestic flights.) It was ranked 4th overall in the Airport of the Year 2006 awards named by Skytrax, next to Singapore Changi Airport, Hong Kong International Airport and Munich International Airport.

During FY 2006, KIX, which serves the city of Osaka, had 116,475 aircraft movements, of which 73,860 were international (31 countries, 71 cities), and 42,615 were domestic (19 cities). The total number of passengers was 16,689,658 of which 11,229,444 were international, and 5,460,214 were domestic. Freight volume was at 802,162 tonnes total, of which 757,414 t were international (18th in the world), and 44,748 t were domestic. The 4,000 meter runway 2 was opened on August 2, 2007. Kansai Airport has become an Asian hub, with 499 weekly flights to Asia, 66 weekly flights to Europe and the Middle East, and 35 weekly flights to North America.

In the 1960s, when the Kansai region was rapidly losing trade to Tokyo, planners proposed a new airport near Kobe and Osaka. Osaka International Airport, located in the densely-populated suburbs of Itami and Toyonaka, was surrounded by buildings; it could not be expanded, and many of its neighbors had filed complaints because of noise pollution problems.

After the protests surrounding New Tokyo International Airport (now Narita International Airport), which was built with expropriated land in a rural part of Chiba Prefecture, planners decided to build the airport offshore. The new airport was part of a number of new developments to revitalize Osaka, which had been losing economic and cultural ground to Tokyo for most of the century.

Initially, the airport was planned to be built near Kobe, but the city of Kobe refused the plan, so the airport was moved to a more southerly location on Osaka Bay. There, it could be open 24 hours per day, unlike its predecessor in the city. Local fishermen were the only group to protest, but they were silenced by hefty compensation packages.

A man-made island, 4 km long and 2.5 km wide, was proposed. Engineers needed to overcome the extremely high risks of earthquakes and typhoons (with storm surges of up to 3 meters). Construction started in 1987. The sea wall was finished in 1989 (made of rocks and 48,000 tetrahedral concrete blocks). Three mountains were excavated for 21 million cubic meters of landfill. 10,000 workers and 10 million work hours over 3 years, using 80 ships, were needed to complete the thirty-meter layer of earth over the sea floor and inside the sea wall. In 1990, a three-kilometer bridge was completed to connect the island to the mainland at Rinku-Town, at a cost of $1 billion. Completion of the artificial island increased the area of Osaka Prefecture just enough to move it past Kagawa Prefecture in size (leaving Kagawa as the smallest by area in Japan).

The bidding and construction of the airport was a source of international trade friction during the late 1980s and early 1990s. Prime Minister Yasuhiro Nakasone responded to American concerns, particularly from Senator Frank Murkowski, that bids would be rigged in Japanese companies' favor by providing special offices for prospective international contractors, which ultimately did little to facilitate the participation of foreign contractors in the bidding process. Later, foreign airlines complained that two-thirds of the departure hall counter space had been allocated to Japanese carriers, disproportionately to the actual carriage of passengers through the airport.

The island had been predicted to gradually sink as the weight of the material used to construct the island would cause it to compress downwards. However, by this time, the island had sunk 8 meters, much more than predicted. The project then became the most expensive civil works project in modern history after 20 years of planning, 3 years of construction and several billion dollars of investment. However, much of what was learned went into the successful artificial islands in silt deposits for New Kitakyushu Airport, Kobe Airport, and Chubu International Airport. The lessons of Kansai Airport were also applied in the construction of Hong Kong International Airport.

In 1991, the terminal construction commenced. To compensate for the sinking of the island, adjustable columns were designed to support the terminal building. These could be extended by inserting thick metal plates at their base. Government officials proposed reducing the length of the terminal in order to cut costs, but architect Renzo Piano insisted on keeping the terminal at its full planned length. The airport opened in 1994.

On January 17, 1995, Japan was struck by the Kobe earthquake, whose epicenter was approximately 20 km away from KIX and killed 6,434 people on Japan's main island of Honshū. The airport, however, emerged unscathed, mostly due to the use of sliding joints in its construction. Even the glass in the windows stayed intact. Later, in 1998, the airport survived a typhoon with wind speeds of up to 200 km/h.

On April 19, 2001, the airport was one of ten structures given the "Civil Engineering Monument of the Millennium" award by the American Society of Civil Engineers.

The total cost of Kansai Airport so far is $20 billion. This includes the land reclamation, 2 runways, and terminal and facilities. The additional costs were mostly borne initially due to the island sinking, expected due to the soft soils of Osaka Bay, but after construction the rate of sinking was considered so severe that the airport was widely criticized as a notorious structural engineering disaster. The rate of sinking has since fallen from 50 cm during 1994 to 9 cm in 2006.

Megastructures - Niagara Tunnel Project

The Niagara Tunnel Project is the most recent in a series of additions to the Sir Adam Beck hydroelectric generation complex in Niagara Falls, Ontario, Canada.

First constructed in 1922, the initial Sir Adam Beck power generating station, now abbreviated as SAB 1, derived its water supply from a canal connected to the Welland River. However, due to increased power demand in later years, a second generating station, known as SAB 2, was constructed in 1954. It in turn derives its water supply from two diversion tunnels, each about 9 kilometers in length. In 1958, a reservoir and the SAB Pump were constructed in order to make better use of available water by storing it during periods of low demand and using it in periods of greater demand in order to maximize the efficiency of the stations in regards to electricity supply and demand.

Between 1996 and 2005, Ontario Power Generation, which owns and operates the SAB complex, completed a series of major upgrades at the SAB 2 plant, increasing its potential generating capacity by 194 megawatts. Water delivered by the new Niagara Tunnel will complement this SAB 2 upgrade, and overall will increase the efficient use of the power of the Niagara River.

The Niagara Tunnel is being dug using a Tunnel Boring Machine, or TBM affectionately named "Big Becky" in honor of Sir Adam Beck. The machine will bore a hole about 10.4 kilometers long and about 14.4 meters in diameter under the City of Niagara falls from the Niagara River to the SAB complex. This massive undertaking will create about 1.6 million cubic meters of rock and debris, which is enough to fill Toronto's Rogers Centre baseball stadium to the top. The TBM operates about 140 meters below the ground, and as a result, the vibrations from the machine will not be felt on the surface. The design-build contractor for the project is Strabag AG, a large construction group with extensive experience in large tunnel construction. The tunnel is to be completed in 2010.

• The tunnel creates enough clean renewable electricity to power a city twice the size of Niagara Falls. The generation capacity of SAB 2 will be increased by about 1.6 billion kilowatt hours per year. This is enough to power over 160,000 homes.
• The tunnel is wider than 6 tractor-trailers side by side, and longer than 100 football fields.
• The machine used in the construction of the Niagara Tunnel can bore through over 15 meters of solid rock per day.
• Over 500 cubic meters of water will enter the Tunnel per second.
• 400,000 cubic meters of concrete are used to line the inside of the Tunnel.
• It will take about 3 years to construct the Niagara Tunnel.
• The tunnel is 14.4 meters in diameter — 65 percent wider than the Channel Tunnel, which is 8.6 meters in diameter, and 2.5 times wider than the subway tunnels in Toronto, Canada which is 5.7 meters in diameter.
• Once completed, the Niagara Tunnel will be the largest hard rock tunnel in the world.
• The machine requires 7 megawatts of electricity — enough to power the United Nations Building in New York City.
• The machine uses 85 watermelon-sized cutting teeth on the face and each tooth weighs as much as a male gorilla.

credited to niagarafrontier.com

Megastructures - Rungnado May Day Stadium, Pyongyang - Korea

Rungnado May Day Stadium has 150 000 seats and a total floor space of more than 207 000 square metres. The area of the pitches is over 22 500 square metres. The stadium has eight storeys and is more than 60 metres high from the ground to the roof. The 60 metre long canopy is enough to cover the section of the stands. The pent of the inner roof is 60 metres long and the outer roof 40m long. The 16 arch roofs link with one another like flower petals.

The roofs look like a large flower floating on the clear water of the Taedong, or a parachute which has just landed, so it gives the impression of a dynamic sculpture. The stadium has 80 exits and ten lifts. It was built in two and a half years on the picturesque Rungra Island in the Taedong River, and commissioned on May 1, 1989. Every condition is provided for international games. The football pitch is covered with natural grass, and the 400 metre track and other parts for field events are rubberised.

The stadium has various training halls, recreation rooms, an indoor swimming pool, an ultrasonic bat, a sauna, beds and so on, which are indispensable for the players training and convenience. It also has dining rooms, and a broadcasting room and telex booths. The rubberised indoor running track is several hundred metres long and is on the sixth floor.

Megastructures - Hoover Dam

History Construction of Hoover Dam began in 1931, and the last concrete was poured in 1935 , two years ahead of schedule. President Franklin D. Roosevelt dedicated the dam on September 30,1935. The power plant structures were completed in 1936, and the first generator began commercial operation in October of that year. The 17th and final generator went into commercial operation in 1961.

Hoover Dam was without precedent, the greatest dam constructed in its day. An arch-gravity structure rising 726 feet above bedrock, Hoover is still the Western Hemisphere's highest concrete dam. It is 660 feet thick at its base, 45 feet thick at its crest, and stretches 1,244 feet across the Black Canyon. There are 4.4 million cubic yards of concrete in the dam, power plant and related structures.

Hoover Dam pioneered the Bureau of Reclamation's efforts in multiple-purpose water resources development. The dam controls floods while it stores water for irrigation, municipal, and industrial uses. The dam also provides hydroelectric power generation, recreation and fish and wildlife habitat.

Dam Benefits

Colorado River water irrigates more than a million acres of land in the U.S., and nearly half a million acres in Mexico. The water helps meet the municipal and industrial needs of over 14 million people. As it passes through Hoover's turbines, the water generates low-cost hydroelectric power for use in Nevada, Arizona and California. About 4 billion kilowatt-hours of energy, enough for 500,000 homes, are generated annually:

Irrigation & Storage

Water that was once muddy is now sparkling clear in reservoirs and in stretches of the Colorado River. Hoover and other dams on the Colorado have tamed the turbulent flow, creating clean bodies of water that provide recreation for more than 10 million people each year. These waters have also provided habitats for fish and wildlife in areas that were once nearly barren.

Colorado River water stored behind Hoover Dam irrigates some of America's richest farmlands. Valley and mesa lands in the warm desert climate along the river grow a wide variety of fruits, vegetables and other non-surplus crops throughout the year. Major irrigation projects, which benefit from Hoover's control and regulation of the Colorado River, include the Palo Verde Valley, the Colorado River Indian Reservation, the Yuma and Gila projects in Arizona, and the Imperial and Coachella valleys in California.

By regulating the Colorado River, Hoover Dam assures a steady flow of municipal and industrial water to Los Angeles, San Diego and other cities in the Southwest. Phoenix, Arizona was added to the list when the Central Arizona Project began delivering water in 1985. The Tucson area began to receive project water in 1991. Several agriculture users, a number of smaller cities, and an Indian community between Phoenix and Tucson also benefit from the water availability.

Part of the hydroelectric energy generated at Hoover and Parker dams helps pump water along the Colorado River Aqueduct. The 242-mile-long aqueduct has an annual capacity of 1.212 million acre-feet (1 billion gallons) of water a day. Five pumping stations lift the water 1,617 feet over the mountains between the Colorado River and the coastal plain.

Homes and industries in the Las Vegas metropolitan area receive Colorado River water from Lake Mead through the Robert B. Griffith Water Project, which was completed in 1982.

Hydroelectric Power

Hydroelectric power is created as water rushes through turbines that activate generators. When the water has completed its task, it flows on unchanged to serve other needs. The electricity produced is clean, nonpolluting and, unlike many other forms of energy, renewable.

Through the sale of power and water, a major portion of the money used to construct Reclamation projects is returned to the Federal Treasury. Hoover Dam's approximate $175 million cost was repaid over a 50-year period, with interest. Hoover Dam and power plant revenues from the sale of water and power have repaid approximately $260 million, including interest, to the Federal Treasury, principally from 50-year power contracts that ended May 31, 1987. Several contingencies, including $25 million allocated to flood control, will be repaid with interest over the 30-year contract period which began June 1, 1987.

Water is released from Lake Mead through similar sets of diversion works in both walls of Black Canyon. The water, drawn through the intake towers, flows through pipes called penstocks, to the power plants. The penstocks also can be used to discharge water directly from the reservoir to the river below the dam. The spillways were tested in 1941 and not used again until the record high flows of 1983.

Vital Statistics

Hoover Dam

Height: 726.4 feet (221.28 meters)
Crest Length: 1,244 feet(379.2 meters)
Top Thickness: 45 feet (13.7 meters)
Bottom Thickness: 660 feet (201.2 meters)
Composition: 3.25 million cubic yards
(2.5 million cubic meters) of concrete.

The Reservoir (Lake Mead)

Length: When full 110 miles
Shoreline: 550 miles
Capacity: 28,537,000 acre-feet , including dead storage
Maximum depth: 500 feet
Area: 157,900 acres
Elevation: 1221.4 feet

Megastructures - Millau Viaduct - France

World's Tallest Bridge

When it opened on 17 December 2004, the spectacular Millau Viaduct set new standards in both planning design and construction - without mentioning the record it set as the largest cable-stayed bridge in Europe.

At 2.4km long, and 270m above the river at its highest point, the Millau viaduct spans a 2km valley in the Massif Central mountain range and forms the final link in the A75 highway from Paris to Barcelona. Despite its huge length, journey time over the structure is expected to be just one minute.

The road has two lanes in each direction and cost €400 million. This will be recouped by the builder, Eiffage, under a 75-year concession.

Bridge design

Two major challenges were identified in building the structure: crossing the River Tarn, and spanning the huge gap from one plateau to the other. The solution proposed is unique, using seven pylons instead of the typical two or three. It is several metres taller than that other famous French landmark, the Eiffel Tower.

Famous British architect Norman Foster was in charge of the viaduct's appearance. It has been designed to look as delicate and transparent as possible. Each of its sections spans 342m and its columns range in height from 75m to 235m over the river Tarn. It uses the minimum amount of material, which made it less costly to construct: the deck, the masts rising above the road deck and the multi-span cables are all in steel.

Seven Piers

The seven piers of the Millau Viaduct are sunk in shafts of reinforced concrete in a pyramidal shape, being divided in an overturned V, and the shrouds are anchored and distributed in semi harps. The program utilised hundreds of high-pressure hydraulic cylinders and pumps to push-launch the deck spans in place and a PC-synchronised lifting system to lift the auxiliary piers. Enerpac was awarded the major contract to supply the hydraulic system for lifting and pushing the bridge spans and piers for the bridge.

Intriguingly, the Millau Viaduct is not straight. A straight road could induce a sensation of floating for drivers, which a slight curve remedies. The curve is 20km in range. Moreover, the road has a light incline of 3% to improve the visibility and reassure the driver.

Bridge Construction

Construction began in October 2001, and by November the following year, the highest pier had already reached 100m in height. Launching the deck started in February 2003, and was completed by May 2004.

Unusually, the deck is constructed from a new high-grade steel as opposed to concrete. This helped the deck to be pre-constructed in 2,000 pieces at Eiffage's Alsace factory and GPS-aligned, 60cm at a time.

The Millau Viaduct is supported by multi-span cables placed in the middle. To accommodate the expansion and contraction of the concrete deck, there is 1m of empty space at its extremities and each column is split into two thinner, more flexible columns below the roadway, forming an A-frame above the deck level.

Construction work used approx. 127,000m³ of concrete, 19,000t of steel-reinforced concrete and 5,000t of pre-constraint steel (cables and shrouds). The project needed 205,000t of concrete, of which 50,000m³ will be reinforced concrete. In total, the viaduct weighs 290,000t.

A 3m-wide emergency lane provides increased security. It will, in particular, prevent drivers from seeing the valley from the viaduct.

As the bridge will be exposed to winds of up to 151km/hr, side screens are used to reduce the effects of the wind by 50%. The speed of the wind at the level of the road therefore reflects the speed of the wind found at ground level around Larzac and Sauveterre.

Toll Station

An 18-lane toll station 6km north of the Millau Viaduct is housed under a structure made of a special concrete patented by the group Eiffage. The toll plaza includes a CCTV connection to the viaduct and the highway. It also accommodates technical and administrative services.

Megastructures - The Akashi - Kaikyo Suspension Bridge

The Akashi Kaikyo Suspension Bridge is the longest suspension bridge in the world and it is probably Japan’s greatest engineering feat.

It took two million workers ten years to construct the bridge, 181 000 tonnes of steel and 1.4million cubic metres of concrete. The steel cable used would circle the world seven times.

It has six lanes and links the island of Awaji and the mainland city of Kobe, a distance of four miles. The concept of building a bridge across the Akashi Straits became urgent after a disaster in 1955. A ferry carrying over one hundred children sank after colliding with another ferry, in the busy shipping lane. One hundred and sixty eight children and adults died in the disaster. Political pressure for a bridge increased and in 1988 construction began.

The Akashi Straits is four miles wide at the bridge site with sea depths of one hundred metres and currents averaging fourteen kmph. The Akashi Straits is one of the busiest sea lanes in the world with over a thousand ships per day travelling through it. Furthermore, the bridge is in a typhoon region in which winds can reach speeds of 290 kmph.

The construction of a suspension bridge involves the use of two main cables stretching between two towers. The roadway beneath these is suspended by more cables. To stop the towers, roadway and cables collapsing, they are held at either end by large anchor blocks (the Akashi anchor blocks weigh 350 000 tonnes). In the case of the Akashi-Kaikyo Bridge, suspension bridge technology was pushed to the limit.

The Japanese designers and engineers tested their designs by building complex models. These were tested in wind tunnels which helped them refine the design so that the bridge could cope with severe weather and typhoon conditions. The photograph opposite shows 40 metre long model, set up for a variety of scientific tests.

After vigorous testing had taken place, construction of the real bridge could begin.

The two towers stand on two large circular foundations. The moulds for the two foundations were built in dry dock weighing 15 000 tonnes and 60 metres in height. In March 1989 a major stage of construction was reached with the moulds for the foundations to the towers being towed out to their positions in the sea by numerous tugs. When in position the moulds were flooded with two hundred and fifty million litres of water, taking eight hours to complete. By the time the moulds were full, they were resting on the sea bed.

Each of the two foundations were filled with 265 000 cubic metres of concrete. However, ordinary concrete does not mix with water and so the Japanese had to develop special concrete which was capable of mixing with sea water.

In 1989 work on the two towers began. Each is nearly as high as the Eiffel Tower and is designed to have a two hundred year lifespan. The towers are 283 metres in height and if the foundations are included, this adds a further 60 metres.
Each tower is made up of 90 sections and they were built with absolute precision as the design allowed only a 25mm offset at the top. In order to achieve this level of accuracy each of the blocks were ‘surface ground’ to a precise finish. 700 000 bolts were used to fix each of the towers together.
Each tower is designed to flex / move in storm force conditions. They and even have a special mechanism that counteracts and dampens movement.

When the towers were completed a temporary cable was stretched between both and a wire mesh gangway built so that workers could start construction of the main cables. This temporary gangway can be seen in the photograph to the right. Workers and machinery pulled the main cables from one tower to the other.

Once the main cables and the vertical cables were in position the deck / roadway was fixed hanging below them. This work took place in 1994. Large purpose built cranes were used to lift the sections, 4000 tonnes each, were bolted into position, one after another. 290 sections make up the entire bridge.
The photographs to the right show the cranes in operation and the deck as it was fixed in position, section by section.
Each section has a triangulated form. This means that weight is kept to a minimum and yet each section has maximum strength.

The final section of the deck was bolted in position in September 1998 and the bridge was opened to the public on the 5th of April of the same year.