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Alternative Lifting Methods - Specialized Equipment Design

2DM Associates, Inc. provides rigging contractors with an expertise in the design of specialized lifting equipment. The following examples demonstrate some of the types of equipment designed to date.

Hoffman breast derrick

675-ton Capacity Breast Derrick

2DM Associates president David Duerr, P.E. designed this derrick in 1975 while in the employ of Hoffman International, Inc. This was a single-purpose machine designed to offload from barges the nuclear steam supply system components for a power plant in southern New Jersey. The heaviest of these components were the 660-ton steam generators, one of which is seen at left.

Overhead crane NASA Langley

200-ton Capacity Overhead Crane

2DM Associates designed this portable overhead crane used to change out drive system components at NASA's Langley facility. Due to a tight schedule, the design was based on the use of structural components already owned by the rigging contractor or readily available. The trolley utilized four 40-foot lift 50-tonne capacity chain air hoists.

Gin pole tower system

Tower Lifting System

Following a concept proposed by the rigging contractor, 2DM Associates designed and detailed this 1,000-ton capacity four-legged tower system, first used to install a reactor vessel in an east Texas chemical plant. The most significant characteristic of this system is that the four legs were old gin poles that were no longer considered competitive against the large cranes and tower systems used by other rigging and lifting contractors. This design allowed the contractor to create a new piece of equipment with minimal investment in new fabrication.

The first lift performed with this tower lifting system won the Rigging Job of the Year award in 1991 from the Specialized Carriers & Rigging Association.

Dome assembly lift

Geodesic Dome Assembly Tower

2DM Associates designed this 300-ton capacity lifting system that consists of a single guyed tower encircled by a ring that is raised and lowered by four load falls. 28 padeyes around the ring provide anchorages for slings rigged to the dome structure. The dome can be assembled almost entirely near ground level by assembling the parts from the center and working outward. As assembly progresses, the dome is raised by the tower.

In anticipation of future growth in dome sizes, the tower was designed such that a minor change in the tower top framing to allow the use of six load falls will increase the rated capacity to 450 tons.

Spent fuel cask transporter

Spent Fuel Cask Transporters

Nuclear power plants around the world have begun storing spent fuel in dry storage casks. Movement of these casks around the facility is performed using specially designed and built transporters. 2DM Associates has performed the structural design of twenty-one spent fuel cask transporters manufactured by Lift Systems, Inc., of East Moline, Illinois. This is almost two-thirds of the total number of transporters presently in service. The design requirements for each transporter are generally tailored to the specific conditions of the facility.

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