Hand in hand: Liebherr LTM 1650-8.1 and LTM 1450-8.1 mobile cranes master complex bridge renovation project

The damage to the Wupperbrücke Hammesberg bridge was so severe that it had to be closed to all vehicles weighing over 30 tonnes. In addition, a speed limit of 30 km/h was imposed on the bridge. To keep the closure of this important route as brief as possible, a construction method using prefabricated parts was chosen.

Meticulous planning for an exceptional tandem lift

However, as there was not enough space for a large crane to cope with the immense load on its own, the decision was made to use tandem lifts. On one side of the river, the LTM 1650-8.1 lifted the prefabricated reinforced concrete parts from the low-loaders across the Wupper up to its lifting capacity limit. At this point, the LTM 1450-8.1, which had been positioned on the other side of the river, came to the rescue. Working high in the air, technicians in a safety cage attached the hook of the 450-tonne crane to a special triangular cross beam.

Schares project manager Eric Reichmann explains: "Even the 800-tonne LTM 1750-9.1 wouldn't have been able to install the girders on its own. Furthermore, the transport vehicle would not have been able to drive alongside the crane. There was simply not enough space. So we had to use both banks of the river. The tandem lift solution required a 160-tonne triangular cross beam and an additional mobile crane with a safety cage. For this, we utilised our LTM 1100-4.1 with emergency take down system. When attaching the hook on the lifting gear below the triangular cross beam, different cable lengths were used to achieve a slight inclination of the concrete beams for installation on the slightly divergent abutment heights."

A total of eight reinforced concrete girders, each 32 metres long, were laid across the Wupper in two days using this unusual tandem method. The bridge is scheduled to reopen to traffic in the spring.