Japan's $40BN Kansai Airport is Sinking

Summary

Kansai International Airport, built on reclaimed land in Osaka Bay, revolutionized airport construction when it opened in 1994. Despite being one of the most expensive and innovative projects of its time, the airport faced the challenge of sinking, with its foundation sinking faster than expected. Overcoming these challenges, the airport has undergone multiple improvements, including advanced flood defenses and a major renovation. As it turns 30, the airport remains a vital hub, showcasing cutting-edge civil engineering, and continues to evolve to meet growing demands, with plans for its long-term sustainability still in progress.

Takeaways

• 😀 The Kansai International Airport in Japan was the first airport built on reclaimed land in the ocean and has celebrated 30 years of operation.
• 😀 The airport is renowned for having the longest terminal building in the world and never losing a single piece of luggage.
• 😀 Despite its accomplishments, Kansai Airport faces a significant challenge: it is sinking.
• 😀 The airport, which cost $4 billion (nearly $40 billion in today's money), was built using radical engineering techniques, including sand drains to consolidate the seabed for a stable foundation.
• 😀 Building an airport in the ocean was necessary due to the limited land available in Osaka, and after the Second World War, Japan's economic growth made a new airport essential.
• 😀 Construction began in 1987, and it took 7 years to build, with massive efforts to fill the island with 180 million cubic meters of earth, creating a landmass that was 75 times the volume of the Great Pyramid of Giza.
• 😀 Despite meticulous planning, the airport began sinking at a rate of 5 cm a month, faster than expected, due to unpredictable layers of clay and sand beneath the seabed.
• 😀 The terminal building’s roof was designed in a wave shape to naturally draw in cool air and minimize the need for air conditioning, saving on energy costs.
• 😀 In 1995, a massive earthquake struck nearby, but the airport's flexible design allowed it to withstand the tremors without significant damage.
• 😀 While the airport has faced flooding challenges, such as Typhoon Jebi in 2018, recent improvements to the seawall and runway have helped protect it from further damage.
• 😀 Kansai Airport is now one of the busiest airports in Asia, and with ongoing renovations and flood defenses, it continues to thrive as a regional hub, though its future sustainability remains uncertain.

Q & A

Why was Kansai International Airport built on reclaimed land?

Kansai International Airport was built on reclaimed land because Osaka, Japan's second-largest city, was surrounded by mountains and had limited space to expand its existing airport. The new airport was necessary to accommodate the rapid economic growth and increasing demand for international flights.

How long did it take to construct Kansai International Airport?

It took 7 years to build Kansai International Airport after 20 years of planning. Construction started in 1987, and the airport opened in 1994.

What was the total cost of building Kansai International Airport?

The total cost of constructing Kansai International Airport was $4 billion USD, which is nearly $40 billion in today's money.

What unique challenges did engineers face during the construction of the airport?

Engineers faced significant challenges due to the unstable seabed. The reclamation process required dealing with weak clay layers and unpredictable behavior of the soil, which caused the island to sink faster than anticipated.

How did the engineers deal with the sinking problem of Kansai Airport?

To counter the sinking issue, engineers used sand drains to consolidate the seabed and compact the clay. This process helped stabilize the foundation, but the airport still experienced faster sinking than expected.

What happened to the airport when it began sinking faster than expected?

When the airport began sinking faster than expected, about $100 million was spent to increase the island's height and ensure it remained above sea level, particularly to avoid flooding from rough seas.

What are some of the engineering marvels of the Kansai International Airport terminal building?

The terminal building, designed by Renzo Piano, features a wave-like roof shape that promotes natural airflow, reducing the need for expensive air conditioning. The building is supported by 900 jacks to adjust for uneven settling and is designed to flex during earthquakes without damage.

How did Kansai International Airport fare during the 1995 earthquake?

Despite a massive earthquake in 1995 that devastated nearby Kobe, Kansai International Airport remained unscathed. The airport’s design, including its flexible terminal and runway, helped it withstand the earthquake.

What happened during Typhoon Jebi in 2018, and how did it impact the airport?

Typhoon Jebi in 2018 caused severe flooding at Kansai International Airport, with waves crashing over the seawall, flooding runways and critical areas. The airport was closed for 3 days and did not resume full service for nearly two weeks.

What steps have been taken to improve the flood defenses of Kansai Airport?

In response to the damage caused by Typhoon Jebi, the seawall and runway have been raised in multiple stages to improve flood defenses. The seawall has been elevated by 2.2 meters, and the runway has been raised by a meter and then another 2.7 meters.