Challenge – Saller’s Liebherr cranes complete difficult bridge hoist at night

• LTM 1750-9.1 and LTM 1400/1 position 61-tonne pedestrian bridge using tandem hoist

• Cranes get within 20 centimetres of each other during hoist

• Full track closure requires smooth procedure during the night

Kran Saller GmbH, based in Deggendorf in Bavaria, positioned a component for a pedestrian bridge over a railway track weighing over 60 tonnes using an extraordinary tandem hoist and a massive logistical effort. The difficulty was that the cranes had to be set up for the night job in Munich very close to each other and moved even closer whilst hoisting the load into position.

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It was really tight – there was only around twenty centimetres between the telescopic boom of the more powerful Liebherr mobile crane and the ropes on the telescope guying of the LTM 1400/1 when the cranes’ superstructures reached the trickiest moment of the complex slewing process . But this almost-contact had been precisely planned as such in advance. “Normally we would have hoisted the load with just one crane and an adjustable yoke, but the customer insisted that the work should be carried out using two cranes”, explained Klaus Ruhland, who completed the calculations for the tandem hoist together with Dennis Kase.

Because the LTM 1750-9.1 had to reach over the smaller crane and its boom to pick up the load, the massive nine-axle machine was set up with a 35 metre luffing jib and its telescopic boom was extended to almost 40 metres for the actual hoist. Managing Director and Head Project Manager Franz X. Saller jun. said: “The close positioning of the two cranes was due to the fact that we had to work from the abutment of a road bridge. We were not able to position the cranes on the bridge structure as a result of the support pressures they generate.”

A great deal of manpower and materials were required for the job because the full closure of the rail network for a limited time and the closure of the road for the hoisting and set-up work meant that rapid progress was essential.

But the efficient team Kran Saller GmbH, based in Deggendorf in Bavaria, positioned a component for a pedestrian bridge over a railway track weighing over 60 tonnes using an extraordinary tandem hoist and a massive logistical effort. The difficulty was that the cranes had to be set up for the night job in Munich very close to each other and moved even closer whilst hoisting the load into position.