The Rion-Antirion Bridge
Construction work on the Rion-Antirion bridge started in July 1998. The bridge, which will provide a fixed link between mainland Greece and the Peloponnese, is now almost complete.
The main structure is in a wonderful but terrifying setting. It is in a narrow but deep part of the Gulf of Corinth, where the seabed consists of a thick layer of weak alluvial material, in a region with intense seismic activity and relatively large, although admittedly slow, tectonic movements.
The towers, particularly their foundations, are the real technical achievement of this project. The seabed on which the foundations rest was specially prepared in order to eliminate the effects of earthquakes.
The four towers which will support the earthquake-resistant cable stayed bridge, which at 2,252 metres is the longest of its type in the world, emerge from the middle of the Gulf of Corinth like the heads of enormous screws and can be seen from many kilometres away from all directions.
The soil was stabilized by driving enormous steel tubes measuring 25 - 30 metres in length and 2 metres in diametre into it from a barge which is the only one of its type in the world. Between 100 and 150 tubes were required for each tower. A thick layer of gravel was then laid down on which the towers rest.
The towers, with an elevation of 116.5m and consisting of 4 inclined legs on a base measuring 40 x 40m were placed above this. The top of the tower is a composite structure like in the case of the Normandy bridge. It is at a height of 163.70m above the sea. The total mass of each mast and 560m of deck is 15,000 tonnes. This weight is almost halved by buoyancy.
The deck is supported by 368 stay cables which are anchored at the top in four towers. Because of the high seismic risk in the Gulf of Corinth, the stay cables have been fitted with specially designed paraseismic deviators which are able to withstand lashing movements of +/- 10m without being damaged. The French company Freyssinet is a member of the Grouping of contractors and involved in installing the 4,000 tonnes of stay cables.