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Giant Beams for Composite Bridge Construction


For the construction of a composite bridge crossing a railway line in Germany, ArcelorMittal produced one of the longest steel beams ever rolled and fully-finished at its Differdange mill in Luxembourg. 460 tonnes of heavy beams, tailor-made for this project: 12 HL1000x591 with the length of 42 m and 8 HL920 x534 of 23 m length – a challenge in various aspects!

Steel beams with these extraordinary dimensions were chosen mainly for reasons of time saving in the construction of the composite bridge which crosses a railway line.

The aim was to reduce this time to a minimum (one weekend) since closing a railway line is connected with high costs. Production and transport were thus accompanied by a tight time schedule.

The use of high-strength heavy sections allows an incredible slenderness for such a composite bridge (slenderness ratio over 28).

The beams were rolled at the Differdange Grey rolling mill, afterwards they were fully finished (cut-to-length, cambering, welding of studs and plates, coating systems) at the C3P finishing center also in Differdange.

Rolling & Finishing

The rolling of heavy beams in such a length, connected with the high-strength steel quality (S460M), presented a challenge at the Differdange mill. Rolling had to follow an exact time schedule, where temperature and rolling speed (Quench and Self-Tempering technology) were crucial for the result.

In order to withstand the continuous loads of the concrete, after rolling the beams were cambered with a 1500t press.

Shear studs and lifting hooks were welded onto the beams. Whereas the shear studs ensure the composite action with the concrete deck, the lifting hooks guarantee that the beams can be handled by cranes during the whole finishing and construction phase without damaging the coating.

For extra reinforcement due to their length, additional high-quality plates were welded below the lower flange.

After 100 working hours per beam and continuous quality checks, each of them weighed around 30tn.

Next step was surface treatment and painting to ensure the corrosion resistance. After shot and sandblasting, different films of paint were applied.

This process took a week, in a specially prepared room where temperature and air humidity were constantly monitored. Also the 5 coat paint system underwent different quality checks. The final coating system responds to the highest corrosion requirement, which means ensuring for long-time durability in a C5 environment.

Transport

The logistical challenge to transport the 12 steel beams from Differdange to Magdeburg was dared and achieved by the C3P team.

The trip of 800 km was completed in 2 days and many obstacles had to be overcome: road signs and even a street lamp had to be temporarily removed to make way for the giants.

Two beams were loaded onto each truck; a detour had to be found since the direct road connection was not designed for such heavy loads.

The A13 highway in Luxembourg had to be closed for a few hours over night since the trucks had to use the exit lanes in reverse in order to join. The convoy travelled at a speed of 62 km/h and was escorted by the police to guarantee security.

At their destination, a crane lifted them directly from the truck onto their concrete abutment. Thanks to perfect planning and collaboration and expertise of the different teams involved, all beams could be assembled in just one day.

 

The above article produced by ArcelorMittal highlights the innovative solutions available with large hi yield strength hot rolled sections. J Steel’s logistics team can source solutions to deliver similar products to customers within Australia New Zealand and the pacific. Consider the possibilities.