A capabilities meeting at a cement plant last fall turned into an SC&RA 2020 Rigging Job of the Year under $150,000 for Barnhart. It was one of two award-winning projects that included Rigging Job of the Year $750,000 to $2 million.
When the plant was asked to name a project that seemed impossible, they pointed to a 9,600 lb. Bellowseal damper that needed to be removed, which was buried behind steel and handrails and hidden around a corner. Slanted sidewalls didn’t allow for a conventional crane boom or even the ability to drop a hook from above. There were numerous overhead obstructions and over 40 feet of 8 ft. diameter double wall stainless ductwork, which could not be removed.
The solution would require an approach that could bend around a corner 180 degrees, safely lift the damper, remove, and replace. Barnhart’s engineers went to work, collaborating with each other, the customer and Barnhart’s Mason City, Iowa branch. They settled on a unique solution – a double cantilever approach.
“Coupling Barnhart’s Mini Moving Counterweight Cantilever System with a custom length Multi Pick Beam configured as a secondary cantilever allowed us to develop a solution that had never been used by Barnhart before,” said Sales Manager Dan Ford.
As the team developed the plan, they consulted with the manufacturer of the damper to engineer, fabricate, and install a safe lifting point on the damper. The multi pick beam was attached to the primary beam. The unit was lifted by a GMK 275-ton all–terrain crane.
Counterweights and the damper were attached to this secondary cantilever. All components were outfitted with swivels to allow the damper to move in any direction and bend completely around a corner for both extraction and installation.
Barnhart’s crew of riggers and signalmen carefully guided the double cantilever system into position using remote controls, tag lines and radios while the crane operator followed instructions until eventually operating in the blind. They navigated the system between two buildings, under a slanted wall, over the ductwork and around the corner to hook onto the damper. They negotiated these operations with just inches of tolerance to maneuver the beams into position.
The old damper was removed and lifted above the existing ductwork avoiding all obstacles and was safely brought to the ground. The process happened in the reverse order to install the new damper.
The dampers were removed and replaced in one ten-hour shift. Barnhart’s approach saved the company days of work and hundreds of man hours, plus the cost of all replacement materials.