The company Marti AG is using two Liebherr crawler cranes type LR 1160 for a major power station project in the Swiss canton Glarus. Before the two 160 t cranes could be erected on the jobsite their delivery through difficult terrain made high demands on logistics, team and equipment.
The transport of the cranes, weighing 31 t each, was carried out using a material ropeway, which in two sections covers an altitude of 1,650 m. The first section reaches 1,900 m above sea level. From there a 3 km long access tunnel leads to the base station of the second section, where one LR 1160 is being used for the construction of a new gravel plant. The height and width of the mouth of the tunnel are only minimally larger than the standard dimensions of a LR 1160 on a low loader. Drawings, plans and measurements had to be thoroughly checked in order to allow for the transportation of the LR 1160 through the narrow tunnel on a low loader. The second material ropeway leads to the Muttsee, a lake which lies 2,450 m above sea level. Here the second Liebherr crawler crane is assisting in the installation of a gravity dam on the southern shore of the lake.
However, since the crane was attached to the material ropeway at an inclination of 47° during this transportation, the position of the centre of gravity and the force on the points of suspension of the material ropeway varied. As a result the weight of the crane had to be reduced from 38,5 t to 31 t in order to avoid overloading of the individual material ropeway winches. For this reason, amongst other parts, the hoist winch and cylinders were disassembled.
Compact transport dimensions, high performance and the self-assembly system of the LR 1160 are important advantages which also lead to the decision of Marti AG to use the Liebherr crawler cranes for this building project located in an area so difficult to reach.