Terex double works for Penglai
By Sarah Ann McCay13 August 2012
China-based Penglai Jutal Offshore Engineering Heavy Industries Co. Ltd. (pJOE) relied on a pair of Terex crawler cranes to lift a 330 tonne ring gear onto a freighter on behalf of Cosco shipyard.
A CC 6800 and a CC 2500-1 were brought in for the tandem lift operation, which presented challenges due to difficulty managing the load's centre of gravity. According to Mr Chen, the Penglai Jutal director responsible for the project, using the IC-1 touchscreen control system in both cranes, along with the load moment indicators (LMIs), enabled the operators to perform a synchronised tandem lift.
The CC 6800 was set up with an SSL configuration, a 90 metre main boom, a 40.5 m superlift mast, a working radius of 24 m, a superstructure counterweight of 250 tonnes, and a central ballast of 80 tonnes. The CC 2500-1 was also set up in SSL configuration but with 72 m main boom, 30 m superlift mast, a superstructure counterweight of 160 tonnes, a central ballast of 40 tonnes, and a working radius of 15 m. To pick up the load safely and with stability, the two crawler cranes worked with spreader beams.
The load was lifted about 4 m moving towards the cargo ship. The CC 6800 stopped and slowly lowered its main boom while the CC 2500-1 kept moving forward until the load was at a working radius of 24 m relative to the CC 6800. The two cranes then continued travelling forward together until they finally lowered the ring gear in place aboard the ship.