Penglai Jutal assembles rig

17 October 2012

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Engineering service provider Penglai Jutal assembled an offshore oil platform, lifting steel framework, on the coast of Penglai in China.

The firm used two Terex CC 6800 and two Terex CC 2500-1.

After hoisting the 470t (518USt) steel formwork, it needed to accurately butt joint the huge 75 x 22m steel pipe framework on top of a section so it could be welded.

This was a challenge, requiring tolerance margins of under a centimeter, as the pipes of these frames are 75m (246ft) long.

"In our field, everything is meticulously planned and calculated, and working with cranes that provide the degree of accuracy and reliability is crucial."

After a test run the four cranes simultaneously lifted the framework to clear the ground to a height of 8m (26ft) and then steadily crawled forward 10m (33ft).

Maintaining the angle of approach, the cranes hoisted to different heights.

After operators configured the crane with114m (374ft) main boom elevated 81 degrees at 21m (67ft) radius, and 360t (397 USt) of total counterweight and central ballast, the two CC 6800s lifted their end of the framework up to 57m (187ft).

On the opposite side, set-up with a 74m (243ft) main boom elevated 83 degrees at 14m (46ft) radius, and a total counterweight and central ballast of 180t (198USt), the two CC 2500-1s lifted their share of the load to a height of 41m(134.5ft).

The cranes picked and carried the load for 75m (246ft) until arriving face to face with the previously secured section of the frame structure.

From this point forward, it was a question of finely tuning and coordinating the cranes' hydraulic movements to join both sections together on a precisely calculated incline.

Penglai Jutal team's technicians guided the company's four crane operators over the phone.

The operators brought the two loads together to form a butt joint at the required position and angle.

The framework was then secured in position by jacks, ready for welding.

Penglai Jutal does Terex offshore lift with two Terex CC 6800 and two Terex CC 2500-1.