5.5km long Thirra Tunnel for the Albania-Kosovo Highway secured by DSI Systems

Once completed, the new Albania- Kosovo Highway will link Kosovo with the seaport of Durres on the Adriatic Sea, crossing Albania. The travel route will then be much easier and shorter, thus significantly contributing to increasing trade and tourism in this area of northern Albania.

On the Albanian side, 1,858m high Mt. Runes divides the planned highway section between the towns of Rreshen and Kalimash. Engineers decided to guide the new highway through the mountain in a 5.5km long double tube tunnel. Tunneling work for the Thirra Tunnel started in May 2007 from all four portals simultaneously. In its production facility in Pasching near Linz in Austria, DSI produced anchor systems and rock support for the Thirra Tunnel and supplied them to the site in accordance with project progress. The support systems were continuously adjusted in the plant to suit new requirements. During excavation work, changing rock conditions were repeatedly encountered in five different zones. This required a huge amount of flexibility and quick recalculation and adjustments of the support systems that were needed. The characteristics of the IBO - Self-Drilling Anchor System – quick and safe application due to drilling, installation and grouting in a single operational step – constituted a huge advantage for the project team. The changing rock conditions also required an ad hoc adjustment of the anchor lengths, which could be done any time using the included couplers. Immediate support in the excavation area was achieved using 95/30/20 Lattice Girders. The Lattice Girder stiffeners (also known as “spiders”) reduce local buckling lengths of the bars and, in addition to a high normal and bending moment resistance, provide an assured transfer of the normal forces prior to the application of shotcrete. The complete integration of the Lattice Girders in the shotcrete lining results in a tunnel lining that significantly reduces ground deformations and prevents the ingress of water. The Thirra Tunnel was opened to traffic in July 2010.