Roadbuilding Odyssey
Greek Motorway: A Mountain Full of Faults and Limestone
The Klovoka tunnel, thought by some to be unbuildable, was completed in little over a year through a mountain full of gases and weak material.
PHOTO COURTESY OF NEA ODOS
While Olympia Odos is the largest single concessionaire project of the five, Greece’s Gek Terna and Spain’s ACS and Ferrovial are the key players in two of the others—Nea Odos and Kentriki Odos, totalling over $2 billion. Nea Odos is wrapping up work on a new Ionia Odos motorway that runs 196 km from the Antirio area to Ioannina in western Greece. Nea Odos has also operated 180 km of existing motorway since 2008, says Stellos Pentheroudakis, CEO for both concessionaire groups. The project, nearly complete and opened in sections, will cut travel time from Antirio to Ioannina by 2 hours from the current 3.5.
The new alignment, with 24 bridges as long as 540 m and four tunnels, cuts through rugged Ioanninan terrain with major geotechnical difficulties. Klokova tunnel, the highlight of the work, creates a link between the Rio-Antirion bridge with western Greece. Mandated by the state to be built in 30 months, the tunnel finished in 25 months, despite what initially seemed to be intractable conditions.
“The mountain is full of faults and limestone,” says Pentheroudakis. Sinkholes, various gases and overburden of 560 m caused many to believe that building a 3-km-long, 11-m-dia pair of tunnels would be impossible, says Malandrakis Eleftherios, Nea Odos project manager. Crews built a self-supporting dome to buffer the drill-and-blast work from karst formations at the portals. Unexpected amounts of flysch prompted crews to utilize four 50-m movable concrete formwork systems building 12 sections of secondary lining. Working from both ends of both tunnels simultaneously, crews completed the lining in 20 months while also building cross-passages that doubled as construction staging spaces.
The 231-km Kentriki Odos project—considered a key component of the Trans-European network—includes upgrades to 57 km of existing motorway and extends E-65 by 174 km, creating a link to the other motorways from northwest to southeast through the heart of Greece. It includes seven twin tunnels, 146 bridges and 88 wildlife crossings. However, the state is still seeking its share of funding for the northernmost and southernmost sections, over 100 km worth. “We as the concessionaire have all the necessary loans and funds and we are ready to restart construction ASAP,” says spokesperson Fotini Lamprou.
Related Article: How a Greek Motorway P3 Survived Upheavals
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