Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering Transport Technology
B.J. von Morgen
Computer program, Report 88.3.OS.2244, Transport Engineering and Logistics.
In order to build production platforms, the deck is divided in several modules. Such a module contains equipment which has a specific function. The module is constructed on shore at a construction yard. A barge transports the module to the productionplatform. The installation is done by a crane vessel. There are different configurations possible to connect the crane hook to the module. The normal 4-points lift is a configuration in which the slings are connected directly to the crane hook and module. This configuration is statically indeterminated, therefore the load on the slings can vary. The use of spreader beams or lifting frames give a more equal load on the slings.
The weight and centre of gravity determine the load on the slings. Therefore they must be known accurately. The stiffness of the module and slings play a part in the distribution of the load on the slings.
A calculation program can be used to calculate the sling loads. The unknown variables are calculated by means of an iteration process. Because such programs are not used at present, certifying authorities apply regulations which are more strict than necessary.
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