Rion Bridge in Greece crosses the Gulf of Corinth
Greek Republic President Karolos Papoulia headed a list of dignitaries celebrating new awards and the naming of the bridge over the Gulf of Corinth between Rion and Antirion May 26. Most members of the group were oblivious to work under way to deal with the second of two structural adjustments to mitigate threats from freak climatic events.
Rising from footings big enough to cover one and a half football fields, a five-span, concrete 2.25-km-long cable- stayed bridge forms the main section of the crossing. Among novel features is its deck, which is seismically isolated. Supported solely by cables, the deck makes no direct contact with pylons or abutments.
Work costing nearly $7 million to attach dampers to the longest 208 cables is now nearly done. Fixed to the deck, the damping pistons are clamped to the cables to prevent troublesome vibrations from reoccurring.
The vibrations were likely caused by frost changing the cables’ aerodynamic profile, says a senior design consultant associated with the project. Since frost is extremely rare in the region, the dampers may be a conservative option, he suggests.
Retrofitting dampers, cross cables or both, was always a reserve strategy, says Patrick Gernigon, a design project manager at Paris-based Vinci Construction. Vinci led the consortium Gefyra S.A., which developed and won the bridge’s build-operate-transfer contract in the mid-1990s.
Unluckily, attaching clamps onto the stays’ plastic casings for possible future cross cables may have attracted trouble in 2005. The metal clamps are thought to have contributed to a lightning strike severing one of the longest cables, causing relatively minor damage below.
The cable was likely out of the protection zone of pylon-top lightning conductors, engineers have concluded. After extensive studies, Gefyra has added an inconspicuous lightning conducting cable above each stay fan, says Vice Chairman and Managing Director Christophe Pélissié de Rausas.
The bridge’s structural adjustments did not distract government officials and construction executives at last week’s celebrations in a marquee by the bridge’s toll plaza. President Karolos Papoulias unveiled a bronze plaque depicting a nineteenth century predecessor, whose the name the bridge now shares.
Harilaos Trikoupi was great Victorian infrastructure builder who called for the Rion-Antirion link to be built long before such a thing was possible. The modern-day engineer who is credited with shaping the bridge’s final implementation was also in the marquee last week to accept two awards for the project.
Speaking in unfaltering Greek, French engineer Jean-Paul Teyssandier acknowledged awards for outstanding achievements from both the International Associating for Bridge and Structural Engineering and the International Concrete Federation (FIB).
Teyssandier, an ENR 2001 Newsmaker for his leading role on the project, took early retirement in 2005, after seeing the bridge through is first year of operations. He had lived with it for nearly a decade and declined to return to head office promotion, say colleagues. No other professional experience could compare with nurturing the bridge from its conception, he says.