6/8: Sinking airport

[stmfreak]

The discovery channel recently ran a special on this. Of note:

Engineers predicted the land-fill island would sink either 19 or 27 feet. The problem was they'd never estimated compression of the deep clay present three miles out. They knew this was a risk, but these were the best estimates they could make. The contractor(government?) made a bet on the cheaper 19' estimate. After the landfill was mostly done, it had already sunk more than those 19', whoops. They had to add an extra 15' of fill (the numbers were all kind of hazy and it should be underwater by 2007 or so if accurate).

Anyway, the bigger problem was the concourse building which is too long (over a mile) and sinks at different rates due to variences in the foundation. The solution was real-time monitoring of the stresses and shimming the structural supports as necessary (a constant, daily, process). Without shimming, the structure would rip apart.

In short, they knew what they were doing, but someone made a cost-based decision and doomed the airport. Of course, at some point the sinking should stop. Question is: When?