The National Road Karditsa - Arta serves as a link between Thessaly, in central Greece, and the Ionian coast. The operation of the road, as it is today, faces serious problems due to its inadequate geometrical characteristics, bad weather conditions during winter, the lack of drainage system and also due to landslips, which occur frequently along the road.
The Department of Public Works of the Thessaly Prefecture awarded a consortium of consulting engineering companies, led by OBERMEYER, to design the improvement of some existing parts of the road as well as to design entirely new sections on other parts. With the completion of these improvement works and the scheduled construction of the Ionian Road a considerable traffic load is expected.
OBERMEYER is responsible for the geotechnical design of the 11km long section of the N.R. Karditsa - Arta, the design of the 1500m long Tympanon tunnel and the design of all related structural works. The tunnel will be bi-directional with a 41m2 cross-sectional area and it will bypass an existing part of the road, which is usually closed during wintertime due to bad weather conditions. Emergency galleries, a fire alarm system and a ventilation system will ensure safety during the operation of the tunnel.
The main body of the tunnel will be drilled according to the NATM, while the portal areas will be constructed with the cut & cover method. The geological complexity of the tunnel area (mainly limestone and flysch), the large overburden height (up to 340m) and the requirement for minimising any effects on the natural environment during construction are amongst the most important issues to be handled at the stage of design as well as during the construction of the tunnel.
The project is expected to be tendered in 2005.