On the historic silk road

Turkey: Highway Tarsus - Adana - Gaziantep, Anatolia

The 258 km long TAG-highway (Tarsus - Adana - Gaziantep) is one of the most important parts of the Turkish road network and the Trans-European Highway.
This highway, running through Anatolia parallel to the Syrian borders, has become an important connection between Turkey and the Middle East markets such as Iraq, Iran and Jordan - the new road has brought the city Sanliurfa and the Harran-planes nearer to the Mersin harbour and the free trade area Yumurtalik (Tayseb) by overcoming one of the geologically most difficult formations of the region - the Taurus mountains.

Construction work began at the end of 1988 and the first 70 km long stretch between Tarsus and Yilankale was opened to traffic in September 1991. In February 1993 the second 54 km long stretch was opened while the last three lots were passable in 1996. At this last stretch very high viaducts and tunnels were planned which had to be constructed on unstable slopes and in soils with especially difficult geological properties.
15 different consultants and 350 sub-contractors were engaged in this project specified to AASHTO-standards.

An average of 7,000 persons were employed in this project. The highway runs through a total of 6 tunnels and over 13 viaducts, two of which are among the most spectacular in Turkey (the so-called "Special Viaducts" SV 1 and SV 2). These viaducts, designed by IN.CO Ingegneri Consulenti, are 800 m and 400 m long and consist of a steel composite structure on piers with a maximum height of 140 m.

Due to the high risk of earthquakes in this region, the vertical reinforcement of the piers was spliced with DYWIDAG extruded couplers Ø 28 mm a total of over 100,000 pcs. extruded couplers were used.

The Special Viaducts partly have flat foundations, partly they are strengthened with GEWI ^®-Piles Ø 50 mm in the foundations. DYWIT SpA, the Italian member of DSI-Group, supplied the micro-piles.

Installation of DYWIDAG Anchors and Rock Bolts, of GEWI ^®-Piles Ø 32 mm and of strand anchors was planned for slope protection and securing of the excavations for the foundations of the viaducts. DYWIT supplied pre-injected and double corrosion protected bar anchors as well as Bar Anchors with single corrosion protection and Strand Anchors with double corrosion protection.

Finally, DYWIT also provided the reinforcement for the pier heads of the viaducts including couplers and injection accessories. The reinforcement splices are factory pre-torqued prior to delivery.