High steaks

The task of transporting a tower crane to the site of a restaurant development more than 2.5 km up a swiss mountain used the lifting power of the contry's largest helicopter.

Placing the eight-tonne capacity flat top Potain MDT 132 tower crane into position on the Arosa Weisshorn, at an altitude of 2,653 m, took careful planning Potain dealer Stimimann supplied the crane to subcontractor Andrea Pitsch for the restaurant build, which includes staff accommodation, a ski room, cold storage and kitchen, along with an upper floor dining area for 182 people.

Lorenzo Cassani, Stirnimann president and general manager, said that although difficult, the assembly project was not unusual. 'We have our own team of Manitowoc Crane Care technicians on hand who know the region, the environment and the equipment,” Cassani explained.

Stage one saw the transportation of the crane's components to the Midway station, using the mountain's cable car. They were then taken the final 650 m by the Kamov heavy-lift helicopter operated by local company Helog-Heliswiss. The helicopter has 15.8 m coaxial rotors and is powered by two 1,660 kW turboshaft (gas turbine driving a shaft instead of jet thrust) engines.

“The total weight of the crane is 30 tonnes and it is larger than many cranes that would be selected for a project such as this. But the nature of the construction required the lifting ability of the Potain. We fitted a 50 m jib and erected the crane to 22 m height under hook, but we managed all this in only 17 trips with the helicopter,” explained Cassani.

The assembly process was completed in a day but, Cassani explained, that there was still a lot of work to be done once the crane was on site. “For example, to bolt the slew ring to the structure our technicians used their torque wrenches to install 116 bolts. A very difficult task in such an exposed location,” he added.