Øresund Fixed Link: Strengthening the ties

The opening of the Øresund connection in 2000 has led to more than just a link between Denmark and Sweden. For many residents of this region, it has transformed their daily lives. Now, more than 8,000 people reside in Sweden and commute across the Øresund Fixed Link each day to work in Denmark. This Fixed Link isn't just a physical connection; it embodies the cultural and economic collaboration between the two countries, which has been crucial in establishing a competitive economic region within Europe.

The Øresund Fixed Link spans 16 kilometers (km) from coast to coast, carrying a dual two-lane motorway and a high-speed twin-track railway between Copenhagen, Denmark and Malmö, Sweden. It comprises several elements:

• 0.9 km² reclaimed peninsula near Copenhagen Airport, Kastrup, featuring an in-situ cast portal structure leading to the immersed tunnel
• 3.7 km-long immersed tunnel beneath the navigation channel between Kastrup and the island of Saltholm
• 3.8 km-long artificial island south of Saltholm with an in-situ cast portal structure for the immersed tunnel
• 7.8 km-long multi-leveled cable-stayed bridge for road and railway traffic, connecting the artificial island to Lernacken, Sweden

The Øresund Consortium, a joint venture with equal shares held by the Danish and Swedish states, built and operates the link. Since 1993, Ramboll has been the main advisor in the international advisory group Øresund Link Consultants (ØLC), acting as in-house advisor for the Consortium. ØLC’s advisory has comprised work related to the design and construction of the link.

As the leading partner, Ramboll’s scope of responsibilities included:

• Geological/geophysical/geotechnical investigations and modelling
• Technical design basis, including application of the Eurocodes
• Motorway and railway alignment
• Conceptual and tender design of dredging and reclamation works
• Conceptual and tender design of the 3.8 km immersed tunnel for road and rail
• Conceptual design of a 7.8 km single-level bridge solution for road and rail, including a 1.1 km cable-stayed bridge with a 490-metre (m) main span
• Construction management for the immersed tunnel including dredging and reclamation works and environmental impact
• Safety and rescue planning with M&E (mechanical, electrical) & ITS (intelligent transportation systems) installations
• EIA (Environmental Impact Assessment) for feasible sites to produce concrete and steel structures in the Copenhagen area

The 3.8 km-long immersed tunnel comprises 20 prefabricated elements, including two railway tubes, two motorway tubes, and an escape gallery. Each element, measuring 176 m in length, consists of eight segments cast in a single pour. One innovative development in this project was the first ever factory-based immersed tunnel production facility with two parallel production lines fabricating these elements. Ramboll’s scope of work included the detailed appraisal of planning the execution and control of the curing time mitigating quenching cracks with materials, as well as procedures for pretesting and documentation regarding repairs.

The project includes a 7.8 km-long multilevel girder and cable-stayed bridge. Two approach bridges lead to the central cable-stayed bridge, with pylons reaching 240 m above the sea, securing a vertical clearance of 57 m crossings and the Flintrännen navigation channel with a main span of 490 m.

The Øresund connection is located in an environmentally sensitive area, and therefore high environmental requirements were set for the construction and the finished connection.

Peberholm, an artificial island south of Saltholm, was created in part to form a transition between the tunnel and bridge, while also serving as a reserve for hundreds of animal and plant species, several of which are rare. Peberholm has remained largely untouched since its establishment without any form of seeding or planting.

The island also hosts technical facilities for the connection, acting as a turnaround point for emergency services and Øresund Bridge maintenance vehicles. The island is built entirely of seabed materials from Øresund.

Ramboll continues to serve as consultant for the Øresund Consortium, overseeing inspections of concrete and steel structures throughout the connection. Furthermore, Ramboll has performed and updated operational risk analyses, focusing on factors such as estimating time schedules for emergency evacuation procedures and assessing the risks posed by ship collisions.