Derrick cranes are ideal for lifting very heavy loads, and are often needed to lower cranes that have been operated on tall buildings. In Seattle, USA, a 355-mt fly-jib crane was taken out of a 36-storey office block by a Liebherr 200 DR 5/10 Litronic derrick crane. Its intelligent PLC system monitored all crane movements until this high-level dismantling operation has been safely completed.

The derrick’s swing supports can distribute the supporting forces ideally according to the stresses the building is capable of absorbing. Since the derrick outreach is variable up to 25 m, the heavy individual sections of the fly-jib crane that is being removed can be lowered at a sufficient distance from the building. Dismantled sections of the derrick can be lowered through the building’s lift shaft when dismantling has been completed.