fischer fixings secure Polish underwater tunnel

The Swinetunnel, Poland's longest underwater tunnel, was opened to traffic at the end of June. The tunnel runs between the islands of Usedom and Wollin in the town of Swinemünde. More than 50,000 fischer heavy-duty fixings were installed in the tunnel.

The first preliminary works of the tunnel, started in November 2019 and completed in May 2023. On 30 June this year, the city of Swinoujscie celebrated the opening of the Swinetunnel and opened it to public traffic.

A 12-m-diameter two-lane main tunnel and a parallel emergency tunnel have been built. The tunnel, including the entrance sections, extends for a total of almost 1.8 km. It passes under the Swine River at a depth of up to 37.5 m below the water surface and 11 m below the river bottom. 

A TBM (tunnel boring machine) was used to drive around 1.5 kilometres of the Swine tunnel. In addition, the cut and cover construction method was used for the construction, during which the excavation and construction are carried out under a cover cast on slotted walls. The construction method allowed the excavation pit to be reinforced and the corresponding surface above the launch shaft on the islands of Uznam and Wolin to be used. 

Chemical fixing systems and steel anchors from fischer strengthen the reinforced concrete structure and reinforce the tunnel. The anchoring depths, some of which are extreme, are up to 550 mm with rods in diameters M16 and M30 to connect reinforced concrete shells after TBM operation. In addition, the fastening solutions were used to secure platforms and struts for the launch shafts. "We are proud that we were able to meet the demands and requirements for the construction of the Swinetunnel with our fixing solutions and to accompany our clients with our product and service competence from planning to on-site support to the successful completion of the project,” said Oliwer Pietrzak, sales representative of fischer Poland. "Our involvement began with the consultation and dimensioning of the most suitable fixing solutions in cooperation with the planning office. In all further construction phases, too, we stood by our clients as fixing partners, offered technical advice and support on site and assisted in the successful implementation of all fixing tasks." 

The fischer injection mortar FIS EM Plus together with system components was used extensively. Even under extreme conditions, such as earthquakes, in water-filled boreholes and in the event of an outbreak of fire, the mortar safely transfers heavy loads into concrete. As its two European Technical Assessments (ETAs) and its ICC approval attest, it is the reliable choice not only for fixings in concrete but also for post-installed rebar connections. Its assessed (ETA) service life of 100 years is a major advantage for infrastructure projects such as the Swinetunnel, which are expected to be intact for a long time and must maintain the highest level of safety.

The Stuttgart engineering office IEA has furthermore certified that anchorages with the fischer FIS EM Plus have a service life of 120 years. In addition, the fischer Superbond mortar FIS SB was installed together with system components in the Swinetunnel. With its silane technology, the fixing system achieves a very high bond stress resilience for a strong performance and a high level of security confirmed by its ETA for concrete and seismic loads. The variable anchoring depths of the injection mortar optimise the installation time and use of materials. Other mechanical anchoring solutions are also being used in the Swinetunnel, such as the FBN II, FBZ and FAZ II bolt anchors and the UltraCut FBS II concrete screws.