Significant improvement

The planned Semmering Base Tunnel (SBT) is currently one of the most important large-scale infrastructure projects in Central Europe. It forms part of Austria’s new southern railway, which serves as the central axis for trans-European routes from the Baltic coast to the Adriatic. With a total length of 27.3 km, the SBT links the country’s Lower Austria and Steiermark regions. Implenia is the lead company on two of the three sections, Gloggnitz (SBT 1.1) and Fröschnitzgraben (SBT 2.1). Two single-track tunnels, each 7.8 km in length, are being built on the Gloggnitz section, and two of 12.9 km on the Fröschnitzgraben section. Both sets of tunnels are being made through a combination of drill and blast, and excavation, though one part of the Fröschnitzgraben section is being created with tunnel boring machines. Owing to the difficult geological conditions in an extremely heterogeneous mountain with huge fault zones, water ingress of up to 300l/s is forecast. The SBT marks Implenia’s successful entry into the Austrian market for large-scale infrastructure projects.

Photo by öbb/grafebner

940 metres long, 30 metres wide and between 8 and 10 metres high: the enclosure being built to protect the Zurich districts of Schwamendingen and Oerlikon from the noise and pollution of the city-centre motorway is a huge undertaking. The roof of the housing structure is also creating a public park and leisure zone, contributing to a lasting improvement in the quality of life of those who live in the area. With three control centres, a ventilation system with a 20 m chimney, five localised ventilation systems, 15 drainage and SOS bays, four access points for trams, a subway, three auxiliary bridges, two kilometres of surface and track construction, 234 precast concrete beams, each 32 metres in length and weighing 70 tonnes, this is a highly complex infrastructure project. To complicate matters further, traffic has to be able to flow in both directions during construction, a wide variety of different construction trades are involved, and a tram tunnel, which must not be disturbed, runs underneath the motorway for 450 metres. Implenia, working as part of a joint venture, is the lead manager and technical lead for the project, which involves its engineering and special foundations units, as well its trenchless specialists and BIM department. Construction work began in 2018 and will be completed by May 2024.

Photo 1 by Bundesamt für Strassen ASTRA / Raumgleiter GmbH, Zürich

The railway line between Gothenburg and Lund on Sweden’s west coast is one of the country’s key transport links for both passengers and goods. The single track section through the town of Varberg is a vital part of the route, and urgently needs to be expanded to a double track. To enable this, trains will run beneath Varberg from 2024. As well as a tunnel, a new passenger railway station and a new freight station must be built. And all of this has to be done while the trains keep running on the existing line. Completion is scheduled for 2025. The project is structured as an ECI (“early contractor involvement”): Implenia was closely involved in Phase 1 of the process so that its practical construction expertise could be fed in at the concept and pre-planning stage. This work went so well that the client, Trafikverket, awarded Phase 2 to Implenia as well, making it design and build contractor for the Varberg job. It is now bringing its expertise and high standards to the detailed planning and execution. Digital tools play a key role in the management of the whole project.