The power station construction sector requires stronger and stronger cranes. With the latest generation of nuclear power plants in particular, the lifting of extremely heavy unit items is an essential.
Added to this is the fact that pre-assembled modules increasingly require lifting as complete units, which again drives the unit weights upwards. In refineries, too, there is a growing demand for industrial columns to be set up which weigh 1500t and reach 100m in length. And larger and larger cranes are also needed for the preliminary assembly of offshore steel structures such as oil platforms.
With the LR 13000, which is currently under test at Liebherr-Werk Ehingen GmbH, Liebherr is extending the range of crawler cranes - onwards and upwards. The new flagship unit, with a maximum lifting capacity of 3000t at 12m outreach, ushers in a whole new dimension in size for crawler cranes of conventional design.
The new 3000t crawler crane provides a maximum system length of 246m, which is achieved in the configuration of a 120m main boom and 126m luffing fly jib, resulting in a maximum hook height of 240m.
The new LR 13000 from Liebherr is the only crawler crane in this size class which can work without derrick ballast. This is achieved by an extremely powerful slewing ring, developed and manufactured by Liebherr themselves. This slewing ring is capable of transferring high torque, by contrast with the solutions from other manufacturers with ringer systems on the crawler travel gear.
In order to achieve the best possible lifting capacities without derrick ballast, the standard slew superstructure ballast is raised from 400t to 750t. This means that the crane can be used universally in the part-load range when the maximum lifting capacities are not called for on a particular site, and it also makes handling a great deal easier.
Against the background of the enormous size and capacity of the new 3000-tonner, coming up with a concept for the transport of the crane components which would be practical and rational was a major consideration. This conceptual challenge meant that no single component weighs more than 70t. The new LR 13000 in operational order tips the scales at 3500t, which includes 400t of superstructure ballast and 1500t of derrick ballast.
Most of the components are transported with a height of 3.6 m and 4 m in width. A crawler carrier is over 3.5m high, 20m long, and weights about 210t. The track, weighing 82t, is taken off, and when dismantled can be economically transported in containers. The 128t of the track carrier is divided in half, and travels on two low-loaders. The slewing ring, 4.5m wide, is transported in a diagonal position, in order not to exceed a width of 4m. The ballast slabs, weighing 25t, are made of reinforced concrete for reasons of costs. They have exactly the dimensions of a 20-foot container and can be loaded with a spreader.
And when it came to the boom design, economical transport logistics were again a key issue. This meant, for example, that for transport the intermediate elements of the luffing fly jib are pushed into the intermediate elements of the main boom with the aid of rollers.
The drive for the LR 13000 makes use of two Liebherr V8 diesel engines, producing a total power rating of 1000kW/1360hp. These are designed in a redundant format in order to increase crane availability still further.
The cables have some impressive dimensions too. 52mm thick, a total length on each hoisting winch of about 2000m, and a line pull of 62t. To guarantee maximum operational reliability and ensure easy maintenance, all the winches are driven by several independent motors on an internal gearing of the cable drum. This means that the crane can continue working even if a drive unit breaks down, and the unit can be replaced rapidly and easily.
The hook block weighs 111t and is 9.7m high, for lifting up to 3000t. It is of modular design and consists of a maximum of two hooks and six pulley sets, with five pulleys each. It can be configured easily for different operational purposes.
The LR 13000 has a large number of ladders, platforms, and catwalks, with all appropriate guardrails, provided for best possible safe access during the assembly and operation of the crane.
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Wolfgang Beringer is with Liebherr-Werk Ehingen GmbH, Ehingen, Germany. www.Liebherr.com
