This episode we discuss Japan’s Kansai Airport, in an episode of firsts: the first airport on reclaimed land, the first time building a mega project on top of holocene clay, our first vertical infrastructure episode, and our first "what went wrong" episode.

After the building of Narita airport through re-appropriation of lands and the violent protests that followed, Japan was faced with an unprecedented challenge in constructing the Kansai airport. The airport is the first of it’s kind, built on a man-made island 3.7km from the mainland in Osaka Bay, and in many ways is an example of what can go wrong when planning for best case outcomes, with it’s initial $14 billion price tag growing by an additional $6 billion since the airport opened in 1995.

The soil in Osaka Bay is mostly submerged holocene clay, which presents unique challenges compared to building on soil, particularly around the ground settling after construction since you can’t accurately test the ground condition without disturbing and in turn changing it. After initially estimating a total of 5-10m of settlement the island has in fact sunk 13m as of 2016 and continues to sink at a rate of 50cm every year, with no idea when the settlement will end!

In 2018 the Kansai airport was struck by Typhoon Jebi, leading to what Vivian calls a “swiss cheese disaster.” Despite the many systems dedicated to disaster mitigation, each a proverbial slice of cheese, and on September 4 2018 the holes in each of these slices lined up. The first slice of our disaster sandwich occurred when a boat was blown into the nearly 4km bridge connecting the airport to the mainland, stranding approximately 8,000 passengers and staff at the airport while also severing their access to water and electricity, as well as communication lines with the mainland. Normally the airport’s emergency generators would power on, but they had been flooded and half the generators failed to start, and yet another slice lined up as the pumps built to clear the generator room in the event of a flood could not start up with power lines severed. So, while the Kansai airport broke new ground in construction methods and land use, it also stands as a reminder to why it’s best to hope for the best, but plan for the worst.

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Learn more at: MeasuredInMetric.com

Edited by: Astronomic Audio

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