Flying flat top

27 March 2023

A new €50 million educational centre and cable car is being built by Vinci Construction high in the French Alps. To help construct it a Liebherr 150 EC-B flat-top tower crane has been erected on a mountain using a helicopter.

A new educational centre focussed on climate change, plus a new cable car station, is being built at the Montenvers mountain station on France’s largest glacier: the Mer de Glace. It is at an altitude of 1,913 metres, near Mont Blanc, Chamonix, in the French Alps.

Construction company Vinci Construction France worked with crane manufacturer Liebherr to select the right crane for the job. Originally, due to the size of the loads that needed to be lifted, a crane in the 250 tonne class was required. A crane of this size, however, would have been too heavy for assembly by the helicopter which, depending on temperature and altitude, could move a maximum of 3,800kg.

The solution was to adapt the building’s architectural plans and use lighter concrete parts. In this way Liebherr’s eight-tonne capacity 150 EC-B flat-top could be used – as its counter jib weighs 3,600kg and so could be handled by the helicopter. The flat-top also has a flexible design enabling it to be dismantled into several individual parts which helped, adds Liebherr.

Planning was key says Liebherr. An open location accessible to both the helicopter and the trucks with the crane elements was selected about 3.5 miles from the Montenvers mountain station. It was as close as possible in order to keep flight times, and therefore refuelling, to a minimum. From here a Kamov KA 32 A11 BC heavy-lift helicopter from Heliswiss International flew back and forth 30 times to deliver all the crane parts and tower system elements.

These parts were received by four assembly engineers from Liebherr's partner FT Montage and six flight assistants from Heliswiss International who, over the course of around eight hours, connected them to create the 150 EC-B with a tower height of over 40 metres.

The crane, with a 45-metre jib and a hook height of 42 metres, will support the construction of the new cable car station and climate change educational centre until June 2023. The Montenvers redevelopment is due to be completed in December 2024.