A rigging event

Last winter Ohio, US-based PSC Crane & Rigging did an engineered rigging job that began with offloading and transferring an 8 MW Wartsila generator from a rail car onto a nine line Goldhofer trailer and then hauling it to the Indian Power Plant facility near Rensselaer, Ohio.

Weighing some 320,000 pounds (145 tonnes) and measuring 44 feet long, 10 feet 10 inches wide and 14 feet 2 inches high (13 x 3.3 x 4.3 m), the generator was hauled one mile (1.6 km) through town, an easy journey compared with the task of sliding it into the building and positioning it for installation.

At the site the generator was offloaded and then the real challenges began. To be set in line with the opening of the brick façade of the building, the generator had to be rotated 90 degrees and then rigged to move inside the building onto the new concrete foundation. Similar to threading a needle on a much larger scale, sliding the generator into the plant through a tight clearance proved to be an extraordinary rigging event.

At the plant the generator was unloaded in the middle of the street. The existing opening in the building's brick façade, which measured a little more than 10 feet (3 m) wide, had to be enlarged for the almost 11 foot (3.3 m) wide generator to safely pass through. A 13 foot (4 m) wide area of grass in front of the building opening had to be temporarily replaced with compacted gravel.

PSC's rigging plan called for the use of a 500 ton (454 tonne) capacity J&R Lift-N-Lock gantry system with 400 ton (363 tonne) J&R Power Rotator. The generator was suspended from the gantry with a spreader bar arrangement using wire rope slings attached at engineered lift points supplied by the manufacturer. Once the generator was lifted it had to be rotated 90 degrees to be set on an hydraulic slide rail system to slide it into the building.

Once it cleared the building, the generator was jacked up to remove the slide rail system underneath it and to install vibration mounts.

Randy Sever, vice president of operations, says the job was carried out smoothly. “This project was well thought out from the initial planning stages and carried through to project completion,” he says. “The planning, scheduling and utilisation of state-of-the-art rigging applications with respect to this project provided safe work practices for all our employees and overall jobsite safety.” Sever says the rigging equipment selection simplified the rigging tasks and created an overall efficiency to the project schedule, even though snow and icy conditions prevailed. All total, the project required 578 hours, including approximately 80 hours of project management and 20 hours of engineered lift and rigging planning. •