Fast work with a big crane and long boom

Wiesbauer’s new LTM 1650-8.1 was loaded with its maximum 175 tonnes of ballast and had the Y-guy system installed. Photo: Liebherr

Lifting and transport specialist Wiesbauer in southern Germany overcame a series of challenges to quickly install new modular hospital classrooms.

For the job Wiesbauer chose its new 700 tonne capacity Liebherr LTM 1650-8.1 wheeled mobile telescopic crane. It was delivered with both versions of telescopic boom, of 50 and 80 metres long. This project was the first time the crane was used with the long, T5, boom and it was an element critical to the success of the operation.

The job required the crane to lift large modular building units on to the flat roof of an existing clinic building in the city of Heilbronn. They formed a new storey on the building consisting of 750 square metres of new classroom facilities installed in just four days.

Limited available space on site, especially for such a large crane, was one of the challenges on this job. A bigger challenge than the lifting work itself, however, was in the preliminary planning for the job. “We had to pass through quite a narrow section on the access road to the site,” explained Christoph Kriegel, Wiesbauer project manager co-ordinating the operation.

Access for the crane was difficult. It had to make use of its steering programmes to travel backwards between the gatehouse and the wall. Photo: Liebherr

It was a section of the route with a gatehouse on one side and a listed wall on the other. The eight axle crane had to get through while also negotiating bends in the road. “No other crane in this load capacity class is built compactly enough to get through here,” Kriegel said.

Underground shafts and ducting precluded setting the crane up on the other side of the site.

The option

After their initial delivery the 17 by 4.8 metre construction modules had to be reloaded for access to the site. Photo: Liebherr

In addition, at 17 x 4.8 metres, the prefab modules were too large to be transported right into the site. This meant a small wheeled mobile crane at the entrance lifted them onto a truck for transport to within reach of the 700 tonner.

The job could have been done with the short telescopic boom but that would have needed a luffing jib to be added to get the reach but there was insufficient space to erect the boom with such an extension. It meant the only way to get the job done was to use the long telescopic boom.

“We would have needed a luffing jib for the short telescopic mast, but we didn’t have enough space to set it up here,” explained Kriegel.

From the beginning of the planning process it was also a requirement for the mobile crane to be able to retract its boom quickly to allow an air ambulance helicopter to use the heliport 100 metres away. That said, the approach and departure direction for helicopters was changed so crane work could also continue.

Ralf Hoffmann, operating this crane for the fourth time, commented, “I’m already familiar with working with the 700 tonne truck because I also drove our first LTM 1650-8.1. The road trip with the large telescopic boom, for which we had a special permit with a total weight of 106 tonnes, was a bit top-heavy, but it went well. Accessing the site, on the other hand, was actually a bit tricky.”

On its other outings the new crane was used to dismantle a bridge and to lift a 100 tonne generator.

The LTM 1650-8.1 was first shown at the Bauma trade show in Munich, Germany, in 2019. It replaced the venerable 500 tonne capacity LTM 1500-8.1 of which nearly 600 examples were produced. Capacities are higher on the new crane than the outgoing 500 tonne model by between 15 and 50 per cent, according to whether or not the optional boom guying system is fitted, Liebherr said.

Precision placement of the prefab modules on the hospital roof using the LTM 1650-8.1. Photo: Liebherr