Cranes: Big and small developments
By Chris Sleight05 March 2012
The last 12 months has seen some dramatic developments at the top end of the crane segment, with launches of some of the biggest cranes ever built, while manufacturers - and in some cases heavy lift contractors themselves - continue to develop plans for even higher capacity machines.
At the same time there is a clear shift at the light end of the market towards more economical cranes for every day work, with a resurgence in the popularity of truck cranes and more moves towards hybrid machines, combining an all-terrain (AT) crane upper body on a standard road-going chassis.
At the heavy end of the market, it is remarkable not just how big cranes are getting, but how many manufacturers there are competing in this area and launching new models. Last May for example, both Sany and Zoomlion launched 3000 tonne+ crawler cranes. Sany's is the 3600 tonne capacity SCC86000TM, while Zoomlion's is the 3200 tonne capacity ZCC3200NP, both of which have been designed for nuclear power plant construction work in China.
Not to be outdone by its domestic rivals, the early part of this year has seen XCMG announce plans for a 88000 tonne-metre crawler crane, which would have a capacity of more than 3600 tonnes. Targeted at the petrochemical industry, the XGC88000 is being jointly developed with Chinese oil company Sinopec, and will sit in XCMG's range above its existing 1000 and 2000 tonne crawlers.
The emergence of these three Chinese manufacturers as serious makers of heavy lift machines has doubled the number of players in the market, providing new competition for established manufacturers Liebherr, Manitowoc and Terex.
Among these, one of the most interesting new developments in the heavy lift sector is Liebherr's Power Boom (P-Boom). This new boom design features a section of separate, double lattice segments at the lower part of the structure, mounted side-by-side. Further up the boom, the parallel sections merge to form a traditional single lattice structure.
Liebherr says this design, which uses standard lattice components, not only increases lifting capacity, but also opens the door to other applications, as the double structure makes the boom much more resistant to twisting forces. Liebherr is currently testing the P-Boom on its 3000 tonne capacity LR13000, and it says the increased performance effectively takes the crane up to a higher lifting capacity class.
Indeed, Liebherr has described the development of the P-boom as a milestone in the lattice-boom crane sector.
As well as these mainstream manufacturers, more of the world's leading cranes users and owners have taken to designing their own machines over recent years. One of the companies with the longest pedigrees here is US-based Lampson, which announced in 2010 it was developing a 3000 US ton (2730 tonne) capacity crawler crane, the LTL-3000, in conjunction with Hitachi.
Hitherto the largest land-based crawler crane in the world was lifting and transportation contractor ALE's AL.SK190, which has a 4300 tonne capacity and a 141 m main boom.
However, the AL.SK190's 190000 tonne-metre capacity has now been surpassed by Mammoet's PTC 200 DS super heavy lift ring crane, which was shipped to its first project at the end of last year. The 200000 tonne-metre machine is fully containerised and fits into 198 standard 40 ft (12 m) containers along with 24 x 20 ft (7 x 6 m) containers for a total weight of 6125 tonnes.
The surge in popularity of heavy lift cranes has been a remarkable trend over the last ten years, and it is not one that many would have anticipated a decade ago.
Back in 2002 there were only a handful of 1000 tonne capacity cranes in existence around the world, and they were regarded as one-off freaks for special applications. Contrast that to today when there are six global manufacturers offering machines in the 2000 to 3000 tonne+ categories as off-the-shelf designs!
Growth in the power and petrochemical plant construction sectors has been the driver for the heavy lift industry, with plants getting bigger and more numerous, and pressure on fast completion times being ratcheted up. There has also been a trend towards the prefabrication of larger and larger plant components, which in turn need bigger cranes to lift them into place.
A further trend has been the requirement to lift the same loads at longer radii, which also means bigger cranes. This can have an advantage in terms of the construction schedule because it means the crane can be erected - which can be a serious construction project in itself - outside of the active part of the site, so as not to disrupt the schedule.
At the lighter end of the lifting segment, manufacturers are reporting an increasing preference for truck cranes over all-terrain (AT) cranes in capacities up to about 100 tonnes. This is something of a reversal of the trend that began in the 1980s, with more sophisticated AT cranes pushing out entry level products.
But as Link-Belt telescopic boom crane product manager Rick Curnutte said, sometimes the sophistication and associated cost of an AT crane isn't justified.
"The small all-terrain cranes have intricate multi-axle steering that adds complexity and has higher maintenance costs. This makes it difficult for a small all-terrain to be cost-effective," he said. "We strongly believe that technology should only be designed into a crane when it yields a true benefit."
Citing other factors, Manitowoc Cranes global product director for truck cranes Ruben Olivas said, "The biggest single advantage is the flexibility for customers to choose a preferred brand of truck. Many customers have a favoured brand, based on customer support, reliability, heritage etc.
"This fits with preferences for left- or right-hand drive and Tier III or Tier IV engine requirements. Also, commercial carriers for a particular market will already have the required number of axles and axle spacing needed, plus the ability to conform to weight or dimension restrictions."
This resurgence has also blurred the margins between truck cranes, boom trucks and AT cranes to a certain extent. One trend is to make a more cost-effective crane by mounting the upper works of an AT crane on a truck chassis. Jay Barth, Terex truck crane product manager said, "For example, the truck mounted Roadmaster 5300 crane shares the same upper structure with the AC 100/4L, but mounted on a commercial chassis."
There is also a grey area between boom trucks and truck cranes, as Tadano general manager for sales and marketing, Thomas Schramm, said, "Boom trucks used to have no closed cabin, keeping them relatively simple. However, increasing demand for operator comfort and the safe execution of jobs has led to a closed cabin."
According to research by Terex, the most popular class of truck crane globally is the 25 to 50 tonne class. This is partly due to a preference for 25 tonne truck cranes in China - by far the largest truck crane market in the world. However, 25 to 50 tonne machines are also the first choice in North America and Russia. In Latin America and the small European truck crane market there is a stronger preference for 50 to 80 tonne cranes, while 80 tonne+ truck cranes are the second most popular choice in Europe.
It remains to be seen to what extent truck cranes will take bites out of the light AT segment, and how much boom trucks will eat into the truck crane share. According to Mr Olivas, the cut-off for boom trucks is around 55 tonnes as the cost of larger trucks and the special permits required start to make them an unattractive proposition. "However," he said, "this might change as it did in the past when the 40 US ton (36.4 tonne) boom truck was uneconomical, yet today is a popular option."
The move towards truck cranes and boom trucks looks set to continue, particularly with both Terex and Manitowoc owning stakes in Chinese truck crane manufacturers. Both have said they will use these factories to produce cranes for other developing world markets, and if the economics of owning and operating these cranes continue to be persuasive, it could see a sea change in the lighter end of the lifting industry.
Meanwhile, there is also growth at the heavy end of the sector, as cranes for power and petrochemical plants keep getting bigger and bigger.