The Caldwell Group is used to designing rigging gear for specialized environments. One of its latest innovations involved designing and producing an adjustable 46-ton capacity lifting beam for the latest phase of an extensive wharf modernization project at the British Antarctic Survey’s Rothera Research Station. Caldwell specifically designed and manufactured the lifting system to suit the bitter cold ecosystem at the South Pole.
The Caldwell Model 24S-46t-315 is an adjustable bail lifting beam that was delivered by Bishop Lifting, Caldwell’s UK-based partner. It was designed for BAM Nuttall, which is working in partnership with the British Antarctic Survey (BAS), a division of the Natural Environment Research Council (NERC). The goal is to complete a variety of civil projects associated with the new RRS Sir David Attenborough, a research vessel owned by NERC and operated by BAS for scientific research and logistics projects. The improvements to the new wharf include a safer berthing area and more modern equipment for lifting cargo to and from the ship.
The 27-foot long beam was designed by Dan Mongan, special application support, new product development specialist at Caldwell. Due to the extremely cold weather in the Antarctic, steel alloy selection, welding processes and even type of paint used were all important considerations from the beginning of the design of the spreader beam. The beam was based on the standard Model 24 adjustable bail lifting system, but offered a higher capacity. The bail is the connection in which the crane hook is attached.
“The successful utilization of the product on such a marquee project showcases our ability to engineer and ship below-the-hook solutions globally,” said Mongan. “Further, it serves as an example of what Caldwell and Bishop can achieve together; this project involved an extensive design phase, multiple Skype calls and a collaboration of all relevant parties to arrive at the eventual rigging solution.”
At 4.5 feet wide, 6.3 feet tall and weighing 10,100 pounds, the beam was provided along with two patented model 52-58 adjust-a-leg wire rope slings with a full 22 feet of reach. The rigging system will be used to lift 20 wharf frames, the lightest weighing approximately 77,162 pounds.
“The challenge was, in simple terms, to lift heavy loads, each with different centers of gravity,” said Ben Gates, business development director, Bishop Lifting Equipment. “The adjustable bail solved the problem in that it can be adjusted in one direction and the adjust-a-leg slings in the other.”
Mongan explained that adjust-a-leg slings can be locked into place for constant lifts and are ideal for use in rigging applications and machinery moving. They are often used, he said, for loads that are balanced and symmetrical, but with lifting points not located in a position for a level lift. They are also suited for use when lifting loads at any desired angle, simply by lifting the with sling legs at that desired angle.
Over the next decade, British Antarctic Survey’s Research Stations will undergo a comprehensive modernization program in order to ensure that their facilities are able to continue to enable world-leading research.
The new wharf is scheduled to be built over two Antarctic seasons, starting in November 2018 and completing in spring 2020, in order to improve ship and boating operations. The rear section of the new wharf was constructed in the first season, then the front section was attached during the latest phase.
The new spreader bar is rigged to a Liebherr LR-1300 crawler crane that is outfitted with a 144-foot boom.