Tadano ATF 400G-6 performs bridge dismantling

With 18 employees across two locations in Allgäu, Burgberg and Kempten, Germany, Mayer Autokran-Vermietungs-GmbH has established itself as a specialist in crane operations and specialized transportation. For more than 40 years the owner-operated company has even made a name for itself, evan as a ski jump specialist.

”The 440-tonner is a fantastic crane,” said Managing Director Erich Mayer. “Not only does it offer excellent steering and a strong drive train, but it is also compact, manoeuvrable and powerful in spite of its size. It can even be used on difficult terrain, such as that in the Damüls ski resort. 1700 metres high? No problem. And then there’s the fact that the 400-tonner offers excellent load capacities on the main boom and boom extensions.”

He said the crane is a strong piece of kit even without boom suspension system or other additional equipment.

“Just like us, it is up for any challenge thrown at it, and it has all the makings of a top performer in its class,” Mayer said.

A project from the city of Dornbirn in Austria provided the opportunity to prove Mayer right in his assessment of the new crane. It was an emergency situation, a bridge measuring 44 metres long and weighing 58 tonnes, suspended above a gorge about 80 metres deep, was in danger of collapsing. Approximately 10,000 cubic metres of rock had been broken off under the bridge, and the time had come to dismantle the bridge as quickly as possible.

The cranes needed to be able to reach the site quickly and carry enough additional equipment with it without exceeding the legally permitted 12-tonne axle load. The two cranes also had to flexibly support counterweights on site and be ready for action after a short set-up time.

“A special quality of the ATF 400G-6 comes in the form of its 10 counterweight variants,” Mayer said. ”With a maximum of 11 tonnes per unit, the counterweights can be combined particularly flexibly, which represents an enormous advantage – especially on projects such as this. This enabled us to react very quickly to changing conditions on site.”

On site, the crane had a limited space for set up and huge gradients.

Both 400-tonners carried out the job with a counterweight of 138 tonnes each. Due to the inclined position of the bridge and its weight, the cranes were tasked with securing the loads and preventing the bridge from swinging. This was the basis for screwing on and removing the bridge sections step by step. After about 1.5 days, the operation at the “Rappenloch” site was complete.