Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering
Transport Technology

R.A.J. Noordermeer De zwenkondersteuning van offshorekranen.
Masters thesis, Report 93.3.TL.4002, Transport Engineering.

This repport presents an overview of the investigation of an improved rail foundation for heavy offshore cranes. The investigation is part of a graduation project and is executed at Gusto Engineering.

After a certain time cracks have occurred in the concerning railfoundations. The cracks are caused by fatique. A study based on the function and the history of the crane proved this cause. Enforced displacements of the foundation play an important role.

Principle solutions have been generated on the basis of alternative slewing devices and tub-collars. The solutions are based on a relocation of material and functions from the spokes to the collar or tub, to reach a higher material-usagefactor.
An improved torsional resistance of the collar is one way to achieve a relocation. This is not feasible so a rectangular collar with bulkheads remain the best alternative. A shift of material from the spokes to a double rail foundation and double tub is a second way to achieve a relocation. Calculations have proven the feasibility.

A separate transmission of the counter forces and main forces is also investigated. This is done in four designs where the railsupport exists of plates or of a casting. Constructions with a separate transmission are massive and the advantages remain unclear. A lighter construction is found by the use off a castpeace.

Finally a design is selected with a rectangular collar with bulkheads and an casted railsupport. The mass increases with 10 percent in comparison with de Hermod design, but the possible lifetime is above the required designlife of 20 years.

It is recommended to optimise the size of the spokes en tub. In a further stage reduction of the mass to a level equal to or below the original design seems to be possible.

Reports on Transport Engineering (in Dutch)
Modified: 2003.11.30; , TU Delft / 3mE / TT / LT.