The LTM 11200-9.1 is by far the biggest roadable mobile crane yet developed. With a maximum capacity of 1,200t, the crane’s eight section telescopic boom can extend to 100m; a lattice jib can add a further 126m, for a maximum system height of 182m. Mounted on a nine axle chassis, the crane can travel at speeds of up to 75kph.
The crane extends the boom to its full 100m length with its Telematik boom pinning system. Alternatively, a four-part ‘short’ telescopic boom can be used with the four inner telescopic parts dismounted. This principle has already proved itself on the LTM 1500-8.1, on which a boom length of 55m is achieved with the help of a 3m lattice head section.
The luffing fly jib can be extended to 126m and reaches lifting heights of up to 170m. The Y-shaped guying system on the telescopic boom, which can be used on either the four- or eight-part boom, enables the crane to be used for wind turbine erection.
The nine-axle LTM 11200-9.1 can be driven on public roads with a total weight of 108t, including all four outriggers and the complete slewing platform with both winches. The telescopic boom is carried on a separate transport vehicle. The crane carrier is powered by an eight-cylinder Liebherr turbo-diesel engine with an output of 500kW (680hp) at 1,900rpm.
The first unit went to Dutch-based, global heavy lift specialist Mammoet in September 2008. On its arrival in Amsterdam the crane went to work extending the height of a radio tower. The KPN tower in Zuidas, Amsterdam, had been surrounded by new, taller, offices since it was built. In order to maintain clear lines of sight for its 120 transmission dishes, the tower needed to be raised to 146m. The challenge of lifting loads of up to 67t to 112m, with other loads going even higher, in a crowded city centre was an ideal opportunity to show the crane at its best.
The main carrier of the LTM 11200-9.1 arrived at the site along with 16 truck loads of additional components: around five truck loads less than for a crawler with similar capacities, according to Mammoet project manager Kees Herrijgers. For the first five jobs, the crane was fitted with a 55m main boom and a 54m fly jib, to lift loads of up to 67t to a height of 112m
The crane was then configured with a 55m main boom and a 90m luffing fly jib. The crane’s Y-shaped back mast provided additional capacity across the load chart. The back mast and main boom are transported to the site on a separate vehicle, and then fitted to the slewing section using a self assembly system. In this configuration, the crane lifted tower segments each weighing 9.5t to heights of up to 146m.
The crane didn’t get a chance to show off its full 100m main boom until the end of 2008, when Irish windfarm specialist McNally Windhoist used their unit to erect an Enercon E-70 wind tower at Heidenheim, near Nuremberg, Germany. The crane drove direct from Ehingen to the job site.
For this job, the crane was configured with 100m telescopic boom, 16m lattice jib and 6.5m hydraulically adjustable assembly jib. The wind tower was assembled to 98m, and the 55t nacelle mounted on top. The blades were fitted to the rotor on the ground, and the complete 70m diameter, 50t, unit lifted to a sheave height of 115m. The hydraulically adjustable assembly jib allowed the rotor section to be precisely placed.
The LTM 11200’s first tandem lift again supported the wind turbine industry, but in a slightly different way. In Cuxhaven, Germany, Cuxhaven Steel Construction (CSC) is building a hangar and dock, which will be used to fabricate ‘Tripile’ foundations, used to support 5MW offshore wind turbines. As part of the project, CSC is building a 600t gantry crane, able to carry the Tripile’s from the fabrication hangar to the River Elbe.
The gantry, built by Kranbau Köthen, consists of two 65m long, 2.5m wide and 4m high main beams, mounted in parallel on top of 40m high legs. On top of the beams is a machine house measuring 30m by 6m, which weighs 155t.
In February, Mammoet was commissioned to erect the gantry crane. The two giant mobiles first lifted the 250t main beams, placing them on top of the 40m legs. For this part of the job, both cranes were configured with telescopic boom only, each taking one end of the bridge sections. Once the bridge sections were fully assembled, the 155t machinery housing was placed on the beams. For this part of the job, one crane worked with a lattice jib, taking the load close to the centre of the housing. At the end of the machinery housing section, the other crane worked with its telescopic boom extended and no jib.
Liebherr’s designers are still working with the 11200 design. Currently, they are working on a giant telecrawler version of the crane, the LTR 11200. A prototype is currently being built, and will soon undergo testing at Ehingen. The LTR 11200 will use the same superstructure as the LTM 11200-9.1, with the same types of extensions on the boom, like fixed jib and luffing jib. It will be mounted on a crawler base similar to the LR 1400/2-W, Liebherr’s narrow track wind farm crawler. This will mean it can move around the job site on a 4.8m wide crawler base. While lifting, it will be stabilised by a star-shaped set of 13m outriggers.
