Changing cranes

The global construction industry may not be as buoyant as it was ten years ago, but there are sectors that continue to provide a steady stream of work. One of the big trends around the world is the need for more energy, as the global population grows and increasingly migrates from rural areas to urban centres.

This not only feeds into the construction of conventional energy projects, but also renewable schemes. But the lifting sector is not bothered which, as either type of work tends to require large and specialised cranes.

But this flow of work brings challenges, particularly when it comes to on-site space restrictions. Rick Mikut, crawler crane manager of rental company All Erection & Crane Rental Corp in the US, said, “We seem to have less and less room on most job sites. This often means lifting at a wider radius since we have to position ourselves further away from the target. In other words, cranes have to sit further back from the lifting area, whereas previously they could sit in closer. The greater the distance the crane has to sit from the actual lift site, the stronger it has to be.”

The move towards larger individual modules on power and petrochemical plants also plays to this trend for bigger cranes, and this has been one of the most active areas of development for manufacturers over the last few years.

“A typical crane for this type of work is the 1,600 tonne capacity CC8800-1 crawler,” said Rüdiger Zollondz, Terex cranes product marketing director. “There is also the Twin version of the CC 8800-1, which has a kit that adds another boom.”

Other new cranes designed for this type of work include the 1,000 tonne capacity Liebherr LR 11000 crawler crane and 750 tonne LTM 1750-9.1 wheeled mobile crane, both of which are manufactured at Liebherr Werk-Ehingen.

As big as these machines are, they still have to be moved from site to site, which is why the LR 11000 has a transport width of 3.5 m and a height of 3.2 m, and individual component weights can be reduced to 45 tonnes. Similarly, the 9-axle LTM 1750-9.1 can be driven on public roads with a complete telescopic boom on-board.

Liebherr also offers crawler cranes up to 3,000 tonnes capacity. The largest model made by Manitowoc meanwhile is the 2,300 tonne capacity model 31000 crawler crane, which has a variable position counterweight system.

China’s leading crane manufacturers are also active in this super heavy end of the market, and recent months have seen some significant achievements. In November a 4,000 tonne capacity XCMG XGC88000 crawler crane lifted a 2,155 tonne reaction vessel into place on the construction of at a coal liquefaction plant in Shenhua Ningxia, China. Configured with 84 m of boom, the crane tilted up the reactor and rotated it before installing it on its foundations at a radius of 23 m.

Meanwhile, in the sustainable energy sector, the move towards more wind energy is driving the development of different sorts of cranes. Not only are there challenges associated with lifting heavier and heavier nacelles (turbines) to greater and greater heights, but the locations of new wind farms cause complications as environmental pressures demand they are located in increasingly remote areas, including weaker wind regions, up mountains or in forests.

In these cases, tower cranes have become serious contenders for wind power work, as Hans-Martin Frech of Liebherr Werk-Biberach, explained, “The space needed for the erection of a tower crane is only around 40% of the space needed for other lifting appliances. Fewer transport vehicles, and transport vehicles with lower weights are also required.”

For this niche market, Liebherr offers, among others, a new model, the 1000 EC-B 125 Litronic flat-top crane. “The 1000 EC-B 125 has a lifting capacity of 125 tonnes in the six-fall version or 100 tonnes in the four-fall version,” said Mr Frech. “It is ideal for short radii of 31.5 m and 36.5 m and for erecting hub heights of more than 120 m.”

The crane can climb to a free-standing height of more than 100 m, and it can then be anchored to the turbine mast for a maximum hoist height of 170 m.

The use of tower cranes in the wind power sector may be more of a trend for the future. For now, it is large crawler and mobile cranes that are the workhorses, although they are often modified to be better suited to the specific requirements of the job.

Mr Mikut said, “We use the wind attachment (WA) for the Manitowoc 16000, which allows the same 16000 model to lift and install anything from the older and smaller 1.5 MW turbines to the newer 2.5 MW and larger wind turbines on towers between 80 m and
85 m.”

Another adaptation from Manitowoc is new Boom Raising System, which uses a large hydraulic cylinder housed in a 3 m boom insert to raise longer crawler crane boom lengths without the need of an assist crane.

Liebherr meanwhile has developed the SL12D2FB boom system for its 750 tonne capacity LG 1750 lattice boom wheeled mobile crane. This has a series of 3.5 m wide sections (as opposed to the usual 3 m) at the base of the lattice boom, upping the crane’s capacity and allowing it to work on 140 m to 160 m high towers. It can lift 141 tonnes to a height under hook of 143 m, or and 97 tonnes to 160 m, for example.

Also new the market is the Terex Superlift 3800 crawler crane, which can be used to erect wind turbine hubs of around 3 MW to a height of 110 m. “When configured with a 159 m main boom plus 12 m light fixed jib it can lift more than 60 tonnes at 110 m,” a Terex spokesperson said.

The 3800 requires less counterweight than previous models and, for better transport, single components weigh less than 40 tonnes and less than 3 m in width and height.

Telescopic crawlers

Another clear trend in the lifting industry over the last few years has been the emergence of a new type of equipment – crawler cranes with telescopic booms. It is true that a few niche manufacturers have made this type of machine for many years, but now the major players are getting on-board and lifting capacities are going up across the board.

Short set up times, manoeuvrability, flexibility with boom configurations and pick and carry capabilities are key advantages of these machines. On the issue of manoeuvrability, the point of telescopic boom crawlers, as opposed to lattice boom machines, is that it is much quicker to take the boom down and move the crane underneath overhead obstructions if required, which can be important on road, rail and inner city sites.

In the past telescopic crawler cranes sat at the lower end of the capacity scale, but in 2012 Liebherr introduced its LTR 1220. The 220 tonner has a 60 m boom that can be extended with a lattice jib up to 43 m long. The chassis offers improved off road mobility and can be easily relocated between job sites, the company says.

Another advantage of many telescopic crawler cranes is that the boom can be telescoped with a load on the hook, which is impossible to do with lattice boom cranes. Sennebogen’s new 70 tonne capacity 673R has a four section, 36 m boom and two fly jib options of 8 and 15 m, which extend the maximum reach to 51 m. In addition, the crawler track width telescopes to quickly adjust the width of the machine for transport and for work in confined areas.

There is also a move towards telescopic boom crawler cranes for duty cycle applications. For example, Kobelco’s 75 tonne capacity TK750FS and the TK750S, shown at last year’s Bauma exhibition, have booms designed for strength and rigidity. The TK750FS, for example, comes with a third winch capable of freefall operation as standard.

Another factor driving change in the design of telescopic crawler cranes is their pick and carry ability. For example, Link-Belt’s 100 tonne capacity TCC-1100 telescopic crawler has full pick and carry abilities, as does Tadano’s 27 tonne capacity GTC300-EX, which was exhibited at Bauma 2013.

New at this month’s ConExpo-Con/Agg exhibition are two further telescopic crawler cranes, the 130 ton (118 tonne) capacity Tadano Mantis GTC‐1200 – the largest in the company’s range, and the 50 ton (45 tonne) capacity Link-Belt TCC-500.

One engine

And while new crane types are being developed, there are changes afoot in traditional sectors. In the past it has been typical for all terrain cranes above a certain capacity to have two engines – a large one in the carrier for road travel and another smaller one in the slewing upper structure to power the lifting equipment. A growing trend however is to use one engine instead of two.

There are pros and cons to each concept. Arndt Jahns, product manager for all terrain cranes at Terex said, “To have only one engine means you optimise space, maintenance and you save costs. Having one engine also overcomes issues from the effect of the Tier 4 Final regulations, where there is less physical space to put the components.”
One engine also means less weight and less maintenance, but at the same time, a single engine design requires other components to get power from the carrier engine up into the superstructure for lifting work.

Some also argue that it is more efficient to have two engines, each suited to the specific task, than one to meet both needs – even though AT cranes do not pick and carry at the same time – so don’t need to run both engines at the same time.

Thomas Schramm, general manager at Tadano Faun, said, “A large, single engine that is operating all the time will require maintenance at a shorter interval compared to two engines, which only run for half the time.

“Secondly, a smaller engine normally uses less fuel compared to a bigger engine. As a rough calculation, a two engine design can save up to 3 litres of fuel power per hour. Multiply this by 1,500 hours and end users can save 4,500 litres per year. With a litre of fuel priced at € 1.50 [US$ 2.00] per litre, potential savings could be € 6,200 [US$ 8,370] per year. Over ten years there is a potential saving of around € 60,000 [US$ 81,000].”

The one engine design concept has been adopted by Liebherr on its new 300 tonne capacity LTM 1300-6.2, with a mechanical shaft drive from the carrier to transfer power to the lifting superstructure for the upper.

Wolfgang Beringer, spokesman at Liebherr-Werk Ehingen, explained the design, “The mechanical shaft ensures a particularly high efficiency. Low engine speeds in the chassis engine provides sufficient power for crane work. This ensures the economy of the new concept in terms of fuel consumption.”

Terex has also announced a single engine all terrain, the Explorer 5800. With its 230 tonne capacity, the crane falls in the middle category of all terrains. The prototype is currently undergoing testing, with the first deliveries expected in the first quarter of this year.

It all goes to show that even if the construction industry is not booming as it once was – or maybe because of that fact – the equipment and technology being offered by crane manufacturers is changing fast.