OSAKA — Without a 20 billion yen reconstruction effort, those who land at Kansai International Airport may find themselves having to swim to the passenger terminal.
That’s because, six years after it opened, airport officials have discovered that the passenger terminal is sinking faster than originally predicted and is now at sea level.
Earlier this month, Kansai airport officials announced the passenger terminal had sunk by nearly 12 meters since it was opened in September 1994. While it was expected that some of the airport facilities would settle a bit, officials were surprised at the rate at which the terminal has sunk.
When the airport was being constructed back in the late 1980s, local engineers predicted the passenger terminal would sink into the reclaimed land by no more than 11.5 meters over 50 years. Local citizens’ groups and domestic and international civil engineers, however, had stated concerns about the artificial island on which the airport is built.
To make matters worse, not only is the passenger terminal sinking into the island, but the island itself is sinking into the seabed.
Officials have long known that the seabed under the airport was composed of soft sand that would sink under the weight of the island, which was built off the coast of southern Osaka in waters 18 meters deep with nearly 180 million cu. meters of dirt.
While there is nothing they can do about the seabed, in order to keep the passenger terminal from sinking further, airport officials plan to dig a moat around the structure and the adjacent Aeroplaza shopping center.
The moat will then be filled with a mixture of concrete and sand to create a 1 meter thick retaining wall.
“The idea is that horizontal pressure on the wall from the surrounding ocean will compress the terminal base and squeeze water trapped underneath the two buildings to the surface,” said a Kansai airport official.
The cost of constructing the wall is estimated at nearly 20 billion yen. The airport plans to use 14 billion yen of its own money to cover the cost, with the remainder coming from local governments and private businesses.
For the financially troubled airport, which has accumulated debts of 150 billion yen, the announcement that the passenger terminal needs to be shored up has come at a particularly bad time.
Over the past three years, several international carriers, including British Airways and United Airlines, have either completely stopped or greatly reduced service.
At the same time, construction of a second runway, which will cost 170 billion yen, has begun. Money for second-phase construction is coming from the central and local governments.
The unexpectedly high operating losses have already forced the Osaka Prefectural Government to commit an additional 500 million yen in tax revenues to maintaining the current airport.
Now, faced with shelling out more money to pay for a retaining wall around the passenger terminal, concern is growing about the second-runway project.
“At the moment, plans for the second runway call for it to be built exactly like the first. But given the problem with the passenger terminal, those plans will have to be revised. It will be difficult for the runway to open on time, and any changes will drive construction costs up,” said a prefectural government official who used to work for the airport, speaking anonymously.
The second runway, which will be parallel to the current one, is to be completed in 2007, and there is great pressure to have it completed before then, partially in order to compete with the new Chubu International Airport in Aichi Prefecture, scheduled to open in 2005.
There are also plans for a crosswind runway the officials hope to have completed sometime around 2015, although prefectural officials have said that will depend on financing.