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Since May 2018, there have been ten Liebherr 1000 EC-H 40 High-Top tower cranes with very high lifting capacities on the construction sites of the Grand Paris Express. The 1000 EC-H 40 is the largest Liebherr tower crane model operating in France. 鈥淭he deployment of these cranes is interesting. Whereas the tower crane market in France generally demands lifting capacities of between 12 and 16 tonnes, machines with lifting capacities of over 25 tonnes are needed for the Grand Paris Express project. These large cranes are being used to place pre-cast tunnel lining segments at great speed,鈥� says Christophe Zimmermann, Managing Director of Liebherr Grues 脿 Tour France.

The Grand Paris project includes the construction of four new lines (15, 16, 17 and 18) as well as the extension of line 14 to the north and south. As 90 percent of these lines run underground, the majority of the tunnel is being excavated with tunnel boring machines. A total of around 20 tunnel boring machines are being used along the route. These machines work at great depths of 15 to 55 m below the earth鈥檚 surface, at a speed of 10 to 15 m per day. The tunnel boring machines perform several functions, namely drilling, removing excavated material, and laying the reinforced concrete rings, i.e. pre-cast tunnel lining segments, which will form the arched ceiling of the underground railway tunnel. These elements generally weigh between 7 and 8 tonnes and are assembled to form a ring, which normally consists of seven parts. The lining segments are delivered on site by truck. They are then unloaded and stored with the help of a 1000 EC-H, which is equipped with a 4-tonne segment grab, and then lowered into the tunnel structure in batches of two or three. Once there, the pre-cast concrete elements are set down onto material handling wagons and transported to the tunnel boring machine, which then assembles them. The Micromove fine positioning mode enables this to be done with millimetre precision despite the heavy weight of the parts. Other assistance systems, such as the electronic anti-collision system and oscillation damping also ensure precise, safe operation.

The tower cranes are exposed to particularly heavy and repetitive mechanical loads in conditions like this. Eric Klingenstein, Special Projects Manager at Liebherr Grues 脿 Tour, explains, 鈥淭ower cranes are the kind of hoist equipment that can meet the very specific requirements of this production logistics. In actual fact, tower cranes are in continuous operation for several months, and even years, on the construction sites of the Grand Paris. To prevent premature wear of crane components, such as the slewing ring for example, we recommend cranes with high load capacities to our customers.鈥�