LKAB Minerals supplied the two most significant Danish bridge projects with their heavy loose ballast material to support the bridge's stability. However, the use of the dense aggregate for these two projects was different for each bridge
For the Great Belt bridge, the foundations that anchored the bridges needed much weight to remain stable. And during the construction of the Öresund bridge, the caissons that support the bridge deck were filled with LKAB Minerals’ heavy natural minerals.
Heavy natural materials in bridge constructions
Our customers use heavy natural minerals in many bridge projects all over the world. They use this either as loose ballast, as is the case for the two projects, or mix this into concrete and apply it as high-density concrete.
In both situations, the essential feature of the LKAB Minerals products is weight. And the reason to select our heavy minerals is often that within the bridge projects there is a limited available space to put the ballast. Hence a standard product cannot solve the weight issue.
Heavy ballast in caissons for Öresund bridge deck
The Öresund bridge is almost 8 kilometres long and runs between the south Swedish city Malmö and the capital of Denmark, Copenhagen. The bridge has four road lanes and has two railway tracks beneath the road deck. The entire structure has a mass of 82,000 tonnes and is made up of three cable-stayed bridge sections.
LKAB Minerals delivered about 65,000 tonnes of MagnaDense for the Öresund Bridge. The dense material was used as loose ballast in the caissons that carry the bridge deck. During construction, the caissons were empty when transported out to the actual place where they will remain for the rest of there lifetime. At their final position, they were filled with the MagnaDense in the bottom.
Delivery at site
We delivered MagnaDense to our customers in one shipment from Narvik (Norway) to Malmö/Copenhagen port. From this large ship, the heavy material was further transported out to the final position of the caissons with smaller barges. From the barges, the MagnaDense was placed with a wheel loader into a funnel (hopper) and then onto a belt that fed the aggregate into the caissons.
In 1998/99 the customer placed LKAB Minerals’ dense aggregate into the caissons. Until today the material remains in the Öresund bridge and is likely to stay there for the rest of its existence.
Stable Great Belt bridge foundation filled with loose ballast material
To reduce the travel time significantly to cross the Great Belt, a strait between the major islands of Zealand (Sjælland) and Funen (Fyn) in Denmark, the Danish government decided to have a bridge made to replace the ferry service. Once approved, it was clear that the Great Belt Bridge would become the largest construction project in Danish history. Now the Danish citizens can easily cross the Great Belt in 10 minutes opposed to the one hour ferry they had to take before.
Filled concrete boxes
At the beginning of the ‘90s, LKAB Minerals supplied their heavyweight aggregate for the construction of the Great Belt Bridge in Denmark. The construction company created special big “concrete boxes” for this bridge and placed these on each side of the bridge.
The suspension bridge required a very stable foundation on each side as an anchor to the supporting cables. They filled each of the concrete boxes with a certain quantity of locally available material; however, they also did an important part of the ballasting for these boxes with dense material from our Swedes mines. To fill each concrete box they needed a total of 25,000 tonnes.