They are the Harley-Davidson of the crane world (and also made in Wisconsin). Only they are bigger. Much bigger.
The largest crane ever built by Manitowoc is the model 31000, which has a maximum rated lifting capacity of 2,300 tonnes and a cunning Variable Position Counterweight (VPC) system that minimises the crane's footprint.
The first Manitowoc 31000 was shipped to South Korea earlier this year, having been bought by Chunjo Construction Co. Since March it has been working at the Posco E&C liquefied natural gas plant in Gwangyang. And in September it made its biggest pick-and-carry lift to date, moving a 650-tonne cold box. Bigger lifts are coming up: a 900-tonne pick is scheduled for this month and two 1,000-tonne lifts are planned for December and February.
Chunjo’s chairman Chang Hwan Jang was particularly pleased to see the crane’s VPC system come into play for the recent 650-tonne lift. The VPC system minimises the crane’s footprint and ground preparation by suspending the counterweight in mid-air, rather than using a wheeled counterweight trolley, found on other high-capacity crawler cranes. The VPC automatically positions the 31000’s counterweight to fit the required lift and ranges from 8m fully retracted to 29m fully extended.
“It’s great to see this flagship crane performing, making an awkward lift look easy,” Chang says. “The 31000 has a minimal footprint thanks to its VPC but also offers a huge capacity, so it fits our needs perfectly. We are delighted with how well the crane is performing and look forward to seeing the next challenging lift it tackles.”
The Manitowoc 31000 lifted the 55m-high cold box, which measures 9m by 9m, off a flat-bed trailer in tandem with a 600-tonne capacity Manitowoc 18000, also owned by Chunjo. Once airborne and upright, the 31000 took over and carried the load to its final location. The entire operation took less than two hours.
The tight lift was hindered by a high wall to the side of the 31000 that restricted its movement. To avoid this, the crane’s entire 55m main boom was raised to its highest angle, bringing the load closer to the crane and minimising potential swing. The crane is also fitted with a 36m luffing jib.