In 1980 a wind turbine only had an output of 50 kW and a rotor diameter of 15 metres, current offshore wind turbines have reached 11 MW and a rotor diameter of 200 metres, and the trend is rising. Everything is relative, while the popular Liebherr LR 1750/2 crawler crane is often the all-rounder on wind power construction land-based sites, Lars Thomsen, Onsite Project Manager at BMS Heavy Cranes uses it for smaller jobs at the site in Esbjerg, Denmark. The 35-strong BMS Heavy Cranes team in Esbjerg is currently performing a major order: The assembly of 106 wind turbine towers for a gigantic new offshore wind power park near Borkum. Work began in December 2023 and will be completed by the end of 2024. Thomsen's preferred hoists in Esbjerg are three Liebherr LR 11350 high-performance crawler cranes in SDB configuration with 132-meter main boom and 42-meter Derrick.
Esbjerg with 70,000 inhabitants is the centre of Danish offshore wind power activities in the North Sea. Liebherr lattice boom cranes from the successful LR series play a major role in Esbjerg. Their task is to assemble the tower elements into a tower reaching 110 meters high. The fully wired tower is erected on a special platform by the LR 11350 and is being lifted on board by the erection vessel's onboard crane. Four wind power plants i.e. 12 rotor blades, four turbines, and four towers are taken on each trip.
“We are safe up to a wind speed of 13.5 m/s,” states Thomsen. In addition to the LICCON system, which constantly monitors the wind, BMS also uses its own app, which allows those responsible to access the wind data at any time. “This is very important,” says Crane Supervisor Michael Leonard, who normally coordinates installations for BMS in Scotland. “I keep a close eye on the wind and weather and also coordinate with the installation company Fairwind and the wind turbine manufacturer - we only do the lift when we say together that it will be pulled. A tower element weighing 100 tonnes must under all circumstances not be allowed to start swinging.”
The LR 11350 is the perfect choice for handling today’s offshore wind turbines.
The Liebherr crawler cranes in the 1,400-tonne-class used by BMS are permanently upgraded and ballasted with 400 tonnes on the superstructure. For heavy lifts, an additional 260 tonnes of suspended ballast is added. The lifts are complicated and often have to be carried out on special crane tracks. These are very precisely leveled so that the LR´s center of gravity is always perfectly positioned, which is digitally displayed to the driver in real time by the LICCON.
Colin Lehmann operates the LR 11350 and likes smooth operation and a perfect overview of all data and components via the LICCON crane control.
Michael Leonard remarks: “I know all of our Liebherr cranes because I operated them. I interpret every sound during operation and am in constant radio contact with our operators. BMS drivers check the four large LR crawler cranes daily before commissioning. Fixed teams of drivers are assigned to the machines, and work is carried out in two shifts of 12 hours each. Even fog, rain, or darkness do not hinder the work. Cameras on the hook and at the tip of the boom give the driver a perfect view of the hook, ropes, and load. Other cameras monitor the winding and unwinding of the ropes, as is usual with large LR cranes.
BMS-Crane Supervisor Michael Leonard is checking the windspeed with BMS Mobil-App.
The fact is that the LR 11350s will reach the end of its performance in the not-too-distant future. BMS and other rental companies with a focus on the offshore wind industry are in constant dialog with Liebherr in Ehingen, because the turbines are becoming heavier, the towers higher and there is no end in sight - a spiral that, according to BMS, is closely coordinated between wind turbine manufacturers and the crane manufacturer.
Additional ballast is being carried with an SMTP-transporter to speed up the rigging of the crane for heavy lifts.
Liebherr has modified its LR 1750 crawler crane with the upgraded 750-tonne LR 1750/2 model now available. By strengthening the main boom and adjusting the derrick system the crane's load capacity has been increased in some areas by up to 30%. This means that the crane offers much better value for money. The adjustment of the derrick system includes an extension of the derrick boom by 7 m to 38.5 m. As with the "H boom kit" for the LR 1600/2, the strengthened boom systems on the LR 1750/2 together with the derrick system have been given the suffix "H" (Heavy) which stands for powerful, heavy boom systems. The ballast trailer has also been modified as part of the modification to the Liebherr 750-tonne crawler crane. This now has a hydraulic drive unit which means improved handling. The new LR 1750/2 also provides enhanced safety for the operating personnel since the crane has additional platforms and access points and its railings have also been extended and improved. During its modification of the LR 1750 Liebherr ensured that the existing equipment components could also be used on the new LR 1750/2. This is a major benefit for crane contractors who already operate one or more LR 1750 cranes in their fleets.
The LR 11350 crawler crane sets the standard in the crane class over 1000 tonnes (1200 USt). It delivers outstanding load capacities over its entire operating range. This crane is particularly suitable for universal use in offshore handling as it can operate with and without PowerBoom, handling high part weights. Its design principle means that the crane components can be transported easily and at low cost and its set-up times are short. This means that no one part is wider than 3.50 meters (11.5 ft) or heavier than 45 tonnes (99,200 lb). With a wide range of boom systems, the LR 11350 can be used flexibly with or without a derrick system. A ballast trailer and suspended ballast are available for the ballasting system. Its range of features is rounded off by high safety standards and great ease of operation.
One thing is certain for BMS, which operates a fleet of over 100 lattice boom crawler cranes worldwide from Taiwan to Australia, America, and Arabia: “The Liebherr products are top-class machines - especially the erection and the fast dismantling and the excellent LICCON control system make our work easy” states Thomsen. Operators of the super-heavy giants work their way up at BMS from the two-axle LTM 1040-2.1 to large telescopic cranes and crawler cranes. The LTM 1040-2.1 delivers outstanding lifting capacities over its entire operating range. Its long, 4-piece telescopic boom can be extended with infinite adjustment and quickly to any length using a time-tested hydro-mechanical telescoping system. The telescoping process can also be completed whilst there is a load on the boom. A folding jib can be used to achieve a radius of up to 39 meters. In comparison to the slightly smaller LTM 1030-2.1, this mobile crane can handle five tonnes more on its hook.
The LTM 1030-2.1 mobile crane, which was launched in 1997 with the name LTM 1030/2, was the first mobile crane in the world to feature data bus transfer technology. This innovative technology enabled the 2-axle crane to achieve major enhancements in terms of the functionality and reliability of mobile cranes. On the basis of this crane, the LTM 1030-2.1 has undergone a series of revisions and now represents the state of the art of mobile crane technology. Well, over 2500 of these 2-axle cranes have been built. That makes it the best-selling mobile crane in the world and the most successful crane model in the history of all-terrain mobile cranes.
From February to December, the 106 wind turbines are assembled and loaded in Esbjerg - the next orders in Denmark's only North Sea port are already lined up. A power station and a large transshipment site for building materials are disappearing in the neighboring port area - all for wind power and all for BMS.
The LR 11350 is the perfect choice for handling today’s offshore wind turbines.
BMS (Byggerits Maskin Stationer A/S) was founded in 1953 in Copenhagen as a state-owned company and in 1955 it got its first crane with 7 tonnes load capacity. In 1993 it was privatized and developed into one of the largest crane and heavy equipment rental companies – operating worldwide with subsidiaries in all five continents. Today 600 people are working for the company. BMS operates a worldwide fleet of heavy and super heavy telescopic and lattice boom cranes ranging up to 1350 tonnes capacity. BMS has a huge footprint in worldwide wind turbine erection since the 1980s. The premier supplier of telescopic and lattice boom cranes is Liebherr Werk Ehingen (LWE) for many years.
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