Bridge crane removed from Indiana steel facility

Smith Erectors deemed the use of conventional wire rope unstable for the lift, which saw the crane raised 85ft out of the mill. The fibre-based slings were chosen instead, to improve ease of handling, reduce manpower requirements, and increase efficiencies, as well as fitting within tight weight restrictions.

The crane was removed from the plant, which produces around 3m tons of rolled steel each year, in two sections, using a crawler crane. Basketed rigging was constructed around the bridge, and chafe protection was added to the load bearing slings to guard against sharp angles on the equipment as it was being lifted. HMPE wear protection jackets were also used over the 12x12 rope.

Ahead of the lift, Smith Erectors established an accurate D:d ratio. This was essential to understand where the connection points would be and adjust the calculations accordingly, helping to know which size of rope to use. Achieving this figure allowed the team to know the breaking strength of the sling when bending around the bridge.

The assembly was comprised of eight 3in x 25ft Plasma grommet slings, which were attached from the crane hook to the shackle on the structure. A series of eye-to-eye slings of 20ft and 14ft lengths were also used. On the second lift, Plasma eye-to-eye slings were used in a basket configuration around a rolling block.

Cortland’s HMPE Plasma slings eliminated 18,000lbs of rigging weight from the assembly. Following six to eight months of planning, the synthetic rope sling solution reduced rigging time from an estimated 20 hours to just five hours during the one-day project.