At least two supercranes are busy in the nuclear sector. Two examples of the Bigge 125D AFRD, put into duty this year, can be found on nuclear powerplant sites in the U.S.: Plant Vogtle, near Waynesboro, Ga., and V.C. Summer, near Jenkinsville, S.C. The Shaw Group, which is managing both plant expansions, purchased two machines costing more than $50 million each.
Officially, the crane is now called the Shaw HLD 125, or the Heavy-Lift Derrick.
"When you buy a car, you can put whatever name you want on it," explains R.M. "Monte" Glover, senior vice president of Shaw and consortium general manager for the Vogtle expansion.
The 6,800-tonne supercranes are the result of a request for proposals that Shaw put out to speciality rigging companies in advance of the job. "We were looking at different technologies out there, and we looked first and foremost at safety," Glover says. "We asked, 'Has lifting technology evolved in the last 30 years?' The answer was no."
Shaw's requirement was fairly simple: It wanted a machine that didn't have to be moved around on the jobsite. Four bidders offered designs, and Shaw picked a design from San Leandro, Calif.-based Bigge Crane and Rigging Co., a longtime speciality contractor and crane dealer. Standing more than 170 m tall and situated at the center of the jobsite, the cranes can cover both AP1000 reactor buildings during the life of the projects. Each crane will be called upon to lift hundreds of modules weighing up to 1,200 tons at a 122-m radius.
"The crane is up and operational, and it's been through all the load testing," Glover says. "It's quite a piece of machinery."
Aside from Vogtle and Summer, has the slowdown in nuclear construction created less demand for these supercranes? Experts say the machines are finding plenty of work in other industrial environments. Aside from powerplants, you're likely to find supercranes working at shipyards, refineries and oil-platform fabrication facilities, says Pete Ashton, vice president of Bigge.
"What's driving the marketplace to find bigger cranes are heavier capacities to handle these large modules," says Ashton. Speed of construction and safety are two factors driving this trend.
Stick-building "results in an exposure and expense to the contractor," says Joe Collins, heavy-lift manager at Becht Engineering, which helps owners plan extreme lifts. "But more than anything, it is exposure to fall hazards and all the things that are associated with working at heights."
More of these projects are opting to "prefabricate large, extremely heavy modules on the ground level," Collins explains. "We pick it and set it, and the crane goes away."