With 18 employees across two locations in Allgäu, Burgberg and Kempten, Germany, Mayer Autokran-Vermietungs 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, for example, as a ski jump specialist.
Two Tadano ATF 400G-6 cranes worked in difficult conditions to dismantle a bridge at Rappenloach near the Austrian city of Dornbirn
Mayer’s expertise operating in difficult terrain was put to good use when it was called to urgently dismantle a bridge. It was an emergency situation where the 44 metre bridge weighing 58 tonnes was in danger of collapsing. Suspended above a gorge about 80 metres deep, approximately 10,000 cubic metres of rock had broken off under the bridge and the time had come to dismantle the bridge as quickly as possible.
A pair of Tadano ATF 400G-6 all terrain cranes were selected for the job. “The 440-tonner is a fantastic crane,” said Erich Mayer, managing director. ”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. 1,700 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.
On site, Mayer had to contend with limited space for set up and steep gradients. The cranes needed to be able to reach the site quickly and carry enough additional equipment with them 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.”
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 removing the bridge sections step by step. In about a day and a half the operation at the “Rappenloch” site was complete.