Crawlers capable of carrying increasingly heavy loads have seen more demand in recent years, and many leading manufacturers now offer models with the capacity to handle loads in excess of 1,000t.
Kobelco is due to premiere its SL4500 at this year’s Intermat show in Paris, with the company saying it has already sold a number of units to customers around the world. Its 400t lifting capacity is not as large as some of the other new crawlers, but Kobelco says this underlines its “class-leading” performance with a maximum load moment of 4,700tm and a maximum configuration with SHL of 84m main boom with 54m luffing jib or 78m main boom with 66m luffing jib, meaning the total boom length can reach 144m.
Last year’s Bauma show in China featured the launch of a number of supersized crawlers, including the show’s largest crane, the 1,000t Sany SCC 10000; the 650t XCMG QUY 650 from XCMG; and a 500-tonner from FUWA.
The SCC 10000 has a maximum main boom length of 120m and a maximum system length with jib of 96m+96m, while XCMG’s QUY 650 has a maximum heavy boom length of 84m, long boom length of 130m and maximum luffing boom/luffing jib configuration of 96m+96m also. FUWA, formerly known as Fushun Excavator, offers a main boom length of 84m, or 108m with light boom, on its QUY500, which can lift full load at 16m when equipped with a 250t superlift counterweight. Without superlift it can carry 400t at a 7m radius with 72m boom. Maximum boom plus luffing jib length is 72m+72m on this crane.
Elsewhere in Asia, Link-Belt has finished capacity and luffing configuration tests on its 500t Link-Belt 548, with shipments into North America planned for the coming months, while Sany is working with Guangdong Power Engineering Corporation to develop the SCC 16000, a 1,600t capacity crawler crane that will be launched by 2011.
Crawlers with lifting capacities In excess of 1,000t are already being demonstrated on the world stage, with Liebherr’s LR 11350 with 1,350t capacity used in the construction of the infrastructure for an offshore gas platform in Malaysia and a Terex-Demag CC 8800-1 with a capacity of 1,600t used to place a polythene reactor at China’s largest ethylene plant in Dagang.
The LR 11350 offers a maximum lifting capacity of 1,350t at 12m, a maximum load moment of 22,748tm, a main boom of 30m-150m, a lattice jib between 36m-114m, a 42m derrick mast, a derrick ballast of 660t and a total counterweight of 1,000t. Terex-Demag’s CC 8800-1 features a maximum load moment of 24,002tm, a 60t central ballast, a 295t counterweight, a superlift counterweight of 640t, a superlift counterweight carrier of 640t and a superlift radius between 19m-30m.
For some operations, these supersized crawlers just aren’t big enough. This has seen the development of ultra heavy lift models by a number of crane manufacturers, with Liebherr, Manitowoc and Terex all planning or putting the finishing touch to crawlers with the capacity to handle upwards of 2,000t.
Models such as the CC 8800-1 Twin from Terex-Demag, the big brother of the CC 8800-1. The Twin has a load moment of 43,900tm and can travel on its crawlers while carrying a full load. It uses a twin boom system to build on the CC 8800-1’s lifting capacity with the second boom and superlift mast joined to the first boom with bend resistant cross connectors. It also features a Quadro drive with self-cleaning drive train geometry that provides optimum traction force, according to Terex, and a hydraulically adjustable telescoping system for the counterweight carrier and tray. For independence on site, it has its own A/C power generation unit for floodlights and air conditioning, and an onboard camera system for maximum visibility to increase safety.
Manitowoc’s Model 31000 is undergoing testing this year and is scheduled to be shipped next year, said Mike Wood, global product manager for crawler cranes at Manitowoc. The Model 31000 will have a maximum capacity of 2,300t and includes a number of unique features such as the Variable Position Counterweight (VPC), which extends from the rear of the crane and ranges from just over 8.38m when fully retracted to 28.95m when fully extended. The system automatically extends when more counterweight moment is needed during the lift and is mechanically locked to prevent the counterweight from inadvertently moving during operation. The system’s mechanical actuator is controlled by the crane’s EPIC control system and is deployed based on boom angle and applied load. Because the VPC never touches the ground under normal working conditions, Wood says the amount of ground preparation work needed with a typical lift-enhancing attachment is greatly reduced.
“The unique thing about the Model 31000 is that it doesn’t require a counterweight that rolls along the ground or hangs off the machine,” says Wood. “The use of the unique VPC means the machine can be used in constrained areas and reduces the amount of groundwork needed to be done. You don’t need a wagon for the counterweight and you only have to prepare the groundwork platform from which the crane’s base operates.”
Wood also says that Manitowoc has been thinking hard about the safety aspects of the Model 31000 and working “diligently” to minimise the risk for customers arising from the crane’s large structure. This includes design elements such as platforms on the boom.
“We’ve done everything we can humanly do from a design point-of-view to minimise the risks,” says Wood. “Increasing safety is a very important element for our customers.”
Two Model 31000s have been sold to date to US firms Bulldog Erectors Inc. and Crane Rental Corp, with Wood adding he expects there to be great interest in the crane when they are shipped next year. “We’ve had quite a few inquiries and there’s lots of anticipation,” he said.
Plans for Liebherr’s XXL crane are still officially being kept under wraps at present but Cranes Today understands that it will be based on a normal crawler crane with just one boom. This structure will be made bigger and stronger to allow double the load capacity of the LR 11350, meaning a proposed capacity of around 2,700t, although this hasn’t been confirmed.
While these three cranes remain in their infancy, the UK’s Abnormal Load Engineering (ALE) has already employed its 4,300t behemoth, the AL.SK90, at a job in Saudi Arabia, where it was used to lift a 755t depropaniser column at a petrochemical plant in Jubail. The AL.SK90 was built exclusively for ALE by its research and development unit in Breda, the Netherlands, and has a main mast height of 130m, a load moment of 96,000tm and a lifting capacity of 600t when employed with a quick winch system.
Demand for larger crawler cranes has already been predominantly from the energy sector, such as oil, gas, and renewables, and Wood predicts this will be the same for ultra heavy lift models. Asia, in particular, is providing a lot of demand, according to Wood, with a large number of nuclear energy projects going ahead in the area. However, he says demand will spread into Europe and the US with large wind farms (see pg 32) and power plants offering a market for these huge cranes.
To this end, he says that Manitowoc is constantly looking at the market to see if there is demand for even bigger capacities. “We’re always scratching our heads trying to work out what the next platform for growth will be.”
