Due to the high seismic and windy activity around the Gulf of Corinth, the Rio-Antirrio Bridge is probably one of the most monitored bridge in the world.

Freyssinet stay cable system is specially inspected and maintained regularly, so that every possible problem is noticed ahead of time and a solution implemented beforehand.

  • Concessionaire
    Gefyra SA
  • Delivery date
  • Partner
    Sixense for monitoring systems
Greece - Rio Antirrio bridge

The world’s longest multi-span cable-stayed bridge at its time

This 2,252m-long cable-stayed bridge is composed of three 560m-long main spans and two 286m-long side spans, carried by four pylons rising up to 140m above sea level.

Its 368 stay cables, forming a semi-fan shape, are in two inclined arrangements, with their lower anchorages at deck level and their upper anchorages at the head of the pylons. Each stay cable is made of 40 to 72 parallel, galvanized strands individually protected with an extruded layer of HDPE as well as an outer HDPE duct.


Seismic protection devices

Longer cables are equipped with pendular external dampers designed with stroke limiters to avoid damage during seismic action and to counter wind-induced vibrations.

The anchorages are protected with a paraseismic deviator especially designed for the bridge. They allow free movement of the cable under regular service condition but acts as a guide with a controlled bend during seismic action. At such a time, they work to isolate the anchorage system from angular deviations and bending stresses that would likely reach strand yield strength during an extreme earthquake.

Greece - Rio Antirrio bridge Stay cable system

A long-term regular maintenance plan coordinated by Freyssinet

Freyssinet has developed a maintenance plan that stipulates which elements of the cables must be inspected during the expected 120-year lifetime of the bridge. This maintenance plan also shares the tasks between Freyssinet and Gefyra SA. Gefyra’s inspectors are in charge of the yearly visual inspection of the stay cable system and Freyssinet provides technical assistance and equipment for each specialised inspection. If during a regular inspection a major unexpected event is detected such as signs of corrosion, remedial action is taken immediately.

In addition to the field inspection, Gefyra has integrated monitoring software developed by our sister company Sixense, that carries over 80 sensors, including accelerometers on the deck, pylons and stay cables.

>> Learn more about Sixense scope of work

The good news is that 2022 inspection show that the bridge appears to be in very good condition overall. “Minor corrosion spots were noticed on a few accessories of threaded components, which are always the most difficult to coat for marine environments, but nothing unexpected considering the exposure and the fact that we are now over 17 years after the installation”. Explains Réka Szécsényi.

  • 2
    Years between each specialised inspection by Freyssinet
  • 10%
    Percentage of anchorages examined during each inspection
  • 2024
    Date by which all anchors will have been examined at least once since their installation.

Thanks to regular inspection and a clear audit trail, any issue is taken care of right at the beginning. The maintenance, recoating operation and inspection are very followed by the concessionaire and, given that the bridge was equipped with several high-end systems and refinements, this becomes a nice source of feedback for corrosion coatings and approaches.

Project Manager at Freyssinet Major Projects Department

Corrosion inspection of anchorages

The bridge cable system is designed so that if a strand is corroded, it can be replaced individually without the need to remove or replace the whole cable. The strands are individually protected by three layers and the external duct provides the fourth.

The cables are regularly checked for corrosion during the two-year periodic inspection.

One of the operations involves opening the anchorages to remove the wax surrounding the ends of the highly galvanized strands and the wedge blocking system to check for any corrosion. To reinject the new wax into the anchorages, special heating belts and plates are used as well as a pump that we supply for the purpose of the inspection.

Greece - Rio Antirrio bridge Anchorages inspection
Cable lightning protection system - Greece Rio Antirrio bridge

Cable lightning protection system inspection

Another element that deserves a lot of attention is the lightning protection system, installed in 2008 after a strong lightning strike on the stay cables in 2005. Checking of load in cables, forces of post-tensioning bars at deck and pylon anchorages were part of the regular inspection.

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