Quist b.v. Rotterdam
Maeslantkering , Hook of Holland, 1991-1995
The doors of the Maeslantkering pivot on gigantic steel ball hinges (10 metres diameter) which allow movement in any direction. Until 2050, according to calculations carried out by Rijkswaterstaat, the barriers will have to close for up to thirty hours on average once in ten years. The closing frequency will rise to once in five years from 2050 onwards owing to the predicted rising sea level.